v15.6.0

* Bump matrix-events-sdk to 0.0.1-beta.7

* Update lockfile for matrix-events-sdk-0.0.1-beta.7

CHANGELOG.md

@@ -1,3 +1,92 @@
+Changes in [15.6.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v15.6.0) (2022-02-28)
+==================================================================================================
+
+## ✨ Features
+ * Return send event response from MSC3089Branch.createNewVersion() ([\#2186](https://github.com/matrix-org/matrix-js-sdk/pull/2186)).
+ * Add functions to support refresh tokens ([\#2178](https://github.com/matrix-org/matrix-js-sdk/pull/2178)).
+
+## 🐛 Bug Fixes
+ * [Release] Fix bug with the /hierarchy API sending invalid requests ([\#2202](https://github.com/matrix-org/matrix-js-sdk/pull/2202)).
+ * Fix bug where calls could break if rejected from somewhere else ([\#2189](https://github.com/matrix-org/matrix-js-sdk/pull/2189)).
+ * Fix camera stuck on after call transfer ([\#2188](https://github.com/matrix-org/matrix-js-sdk/pull/2188)).
+ * Fix synthetic read receipt handling ([\#2174](https://github.com/matrix-org/matrix-js-sdk/pull/2174)). Fixes vector-im/element-web#21016.
+ * Revert "Sign backup with cross-signing key when we reset it." ([\#2175](https://github.com/matrix-org/matrix-js-sdk/pull/2175)).
+ * Sign backup with cross-signing key when we reset it. ([\#2170](https://github.com/matrix-org/matrix-js-sdk/pull/2170)).
+ * Fix error in uploadContent() when file is empty under Node.js ([\#2155](https://github.com/matrix-org/matrix-js-sdk/pull/2155)).
+ * Check the backup info against the stored private key when determining trust. ([\#2167](https://github.com/matrix-org/matrix-js-sdk/pull/2167)).
+ * Back up keys before logging out ([\#2158](https://github.com/matrix-org/matrix-js-sdk/pull/2158)). Fixes vector-im/element-web#13151.
+
+Changes in [15.6.0-rc.1](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v15.6.0-rc.1) (2022-02-22)
+============================================================================================================
+
+## ✨ Features
+ * Return send event response from MSC3089Branch.createNewVersion() ([\#2186](https://github.com/matrix-org/matrix-js-sdk/pull/2186)).
+ * Add functions to support refresh tokens ([\#2178](https://github.com/matrix-org/matrix-js-sdk/pull/2178)).
+
+## 🐛 Bug Fixes
+ * Fix bug where calls could break if rejected from somewhere else ([\#2189](https://github.com/matrix-org/matrix-js-sdk/pull/2189)).
+ * Fix camera stuck on after call transfer ([\#2188](https://github.com/matrix-org/matrix-js-sdk/pull/2188)).
+ * Fix synthetic read receipt handling ([\#2174](https://github.com/matrix-org/matrix-js-sdk/pull/2174)). Fixes vector-im/element-web#21016.
+ * Revert "Sign backup with cross-signing key when we reset it." ([\#2175](https://github.com/matrix-org/matrix-js-sdk/pull/2175)).
+ * Sign backup with cross-signing key when we reset it. ([\#2170](https://github.com/matrix-org/matrix-js-sdk/pull/2170)).
+ * Fix error in uploadContent() when file is empty under Node.js ([\#2155](https://github.com/matrix-org/matrix-js-sdk/pull/2155)).
+ * Check the backup info against the stored private key when determining trust. ([\#2167](https://github.com/matrix-org/matrix-js-sdk/pull/2167)).
+ * Back up keys before logging out ([\#2158](https://github.com/matrix-org/matrix-js-sdk/pull/2158)). Fixes vector-im/element-web#13151.
+
+Changes in [15.5.2](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v15.5.2) (2022-02-17)
+==================================================================================================
+
+## 🐛 Bug Fixes
+ * Fix synthetic read receipt handling
+
+Changes in [15.5.1](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v15.5.1) (2022-02-14)
+==================================================================================================
+
+## 🐛 Bug Fixes
+ * Fix issue with rooms not getting marked as unread ([\#2163](https://github.com/matrix-org/matrix-js-sdk/pull/2163)). Fixes vector-im/element-web#20971.
+ * Don't store streams that are only used once ([\#2157](https://github.com/matrix-org/matrix-js-sdk/pull/2157)). Fixes vector-im/element-web#20932. Contributed by @SimonBrandner.
+ * Fix edge cases around RR calculations ([\#2160](https://github.com/matrix-org/matrix-js-sdk/pull/2160)). Fixes vector-im/element-web#20922.
+ * Account for encryption in `maySendMessage()` ([\#2159](https://github.com/matrix-org/matrix-js-sdk/pull/2159)). Contributed by @SimonBrandner.
+ * Send references to thread root to threads, even out of order ([\#2156](https://github.com/matrix-org/matrix-js-sdk/pull/2156)).
+ * Fix initial sync fail when event fetching unsuccessful ([\#2150](https://github.com/matrix-org/matrix-js-sdk/pull/2150)). Fixes vector-im/element-web#20862.
+ * Don't decrypt redacted messages ([\#2143](https://github.com/matrix-org/matrix-js-sdk/pull/2143)). Contributed by @SimonBrandner.
+
+Changes in [15.5.1-rc.1](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v15.5.1-rc.1) (2022-02-08)
+============================================================================================================
+
+## 🐛 Bug Fixes
+ * Fix issue with rooms not getting marked as unread ([\#2163](https://github.com/matrix-org/matrix-js-sdk/pull/2163)). Fixes vector-im/element-web#20971.
+ * Don't store streams that are only used once ([\#2157](https://github.com/matrix-org/matrix-js-sdk/pull/2157)). Fixes vector-im/element-web#20932. Contributed by @SimonBrandner.
+ * Fix edge cases around RR calculations ([\#2160](https://github.com/matrix-org/matrix-js-sdk/pull/2160)). Fixes vector-im/element-web#20922.
+ * Account for encryption in `maySendMessage()` ([\#2159](https://github.com/matrix-org/matrix-js-sdk/pull/2159)). Contributed by @SimonBrandner.
+ * Send references to thread root to threads, even out of order ([\#2156](https://github.com/matrix-org/matrix-js-sdk/pull/2156)).
+ * Fix initial sync fail when event fetching unsuccessful ([\#2150](https://github.com/matrix-org/matrix-js-sdk/pull/2150)). Fixes vector-im/element-web#20862.
+ * Don't decrypt redacted messages ([\#2143](https://github.com/matrix-org/matrix-js-sdk/pull/2143)). Contributed by @SimonBrandner.
+
+Changes in [15.5.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v15.5.0) (2022-01-31)
+==================================================================================================
+
+## ✨ Features
+ * Support m.asset in m.location event content ([\#2109](https://github.com/matrix-org/matrix-js-sdk/pull/2109)).
+ * Send extensible events structure and support on-demand parsing ([\#2091](https://github.com/matrix-org/matrix-js-sdk/pull/2091)).
+ * Support cancelling events whilst they are in status = ENCRYPTING ([\#2095](https://github.com/matrix-org/matrix-js-sdk/pull/2095)).
+
+## 🐛 Bug Fixes
+ * Fix http-api butchering idServer requests ([\#2134](https://github.com/matrix-org/matrix-js-sdk/pull/2134)). Fixes vector-im/element-web#20680.
+ * Don't remove streams that still have tracks ([\#2104](https://github.com/matrix-org/matrix-js-sdk/pull/2104)).
+
+Changes in [15.5.0-rc.1](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v15.5.0-rc.1) (2022-01-26)
+============================================================================================================
+
+## ✨ Features
+ * Support m.asset in m.location event content ([\#2109](https://github.com/matrix-org/matrix-js-sdk/pull/2109)).
+ * Send extensible events structure and support on-demand parsing ([\#2091](https://github.com/matrix-org/matrix-js-sdk/pull/2091)).
+ * Support cancelling events whilst they are in status = ENCRYPTING ([\#2095](https://github.com/matrix-org/matrix-js-sdk/pull/2095)).
+
+## 🐛 Bug Fixes
+ * Fix http-api butchering idServer requests ([\#2134](https://github.com/matrix-org/matrix-js-sdk/pull/2134)). Fixes vector-im/element-web#20680.
+ * Don't remove streams that still have tracks ([\#2104](https://github.com/matrix-org/matrix-js-sdk/pull/2104)).
+
 Changes in [15.4.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v15.4.0) (2022-01-17)
 ==================================================================================================
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "matrix-js-sdk",
-  "version": "15.4.0",
+  "version": "15.6.0",
   "description": "Matrix Client-Server SDK for Javascript",
   "scripts": {
     "prepublishOnly": "yarn build",
@@ -56,6 +56,7 @@
     "bs58": "^4.0.1",
     "content-type": "^1.0.4",
     "loglevel": "^1.7.1",
+    "matrix-events-sdk": "^0.0.1-beta.7",
     "p-retry": "^4.5.0",
     "qs": "^6.9.6",
     "request": "^2.88.2",

spec/integ/matrix-client-crypto.spec.js

@@ -348,7 +348,7 @@ function recvMessage(httpBackend, client, sender, message) {
         return testUtils.awaitDecryption(event);
     }).then((event) => {
         expect(event.getType()).toEqual("m.room.message");
-        expect(event.getContent()).toEqual({
+        expect(event.getContent()).toMatchObject({
             msgtype: "m.text",
             body: "Hello, World",
         });

spec/integ/matrix-client-methods.spec.js

@@ -1,5 +1,6 @@
 import * as utils from "../test-utils";
 import { CRYPTO_ENABLED } from "../../src/client";
+import { MatrixEvent } from "../../src/models/event";
 import { Filter, MemoryStore, Room } from "../../src/matrix";
 import { TestClient } from "../TestClient";
 
@@ -392,6 +393,414 @@ describe("MatrixClient", function() {
             return prom;
         });
     });
+
+    describe("partitionThreadedEvents", function() {
+        it("returns empty arrays when given an empty arrays", function() {
+            const events = [];
+            const [timeline, threaded] = client.partitionThreadedEvents(events);
+            expect(timeline).toEqual([]);
+            expect(threaded).toEqual([]);
+        });
+
+        it("copies pre-thread in-timeline vote events onto both timelines", function() {
+            client.clientOpts = { experimentalThreadSupport: true };
+
+            const eventMessageInThread = buildEventMessageInThread();
+            const eventPollResponseReference = buildEventPollResponseReference();
+            const eventPollStartThreadRoot = buildEventPollStartThreadRoot();
+
+            const events = [
+                eventMessageInThread,
+                eventPollResponseReference,
+                eventPollStartThreadRoot,
+            ];
+            // Vote has no threadId yet
+            expect(eventPollResponseReference.threadId).toBeFalsy();
+
+            const [timeline, threaded] = client.partitionThreadedEvents(events);
+
+            expect(timeline).toEqual([
+                // The message that was sent in a thread is missing
+                eventPollResponseReference,
+                eventPollStartThreadRoot,
+            ]);
+
+            // The vote event has been copied into the thread
+            const eventRefWithThreadId = withThreadId(
+                eventPollResponseReference, eventPollStartThreadRoot.getId());
+            expect(eventRefWithThreadId.threadId).toBeTruthy();
+
+            expect(threaded).toEqual([
+                eventMessageInThread,
+                eventRefWithThreadId,
+                // Thread does not see thread root
+            ]);
+        });
+
+        it("copies pre-thread in-timeline reactions onto both timelines", function() {
+            client.clientOpts = { experimentalThreadSupport: true };
+
+            const eventMessageInThread = buildEventMessageInThread();
+            const eventReaction = buildEventReaction();
+            const eventPollStartThreadRoot = buildEventPollStartThreadRoot();
+
+            const events = [
+                eventMessageInThread,
+                eventReaction,
+                eventPollStartThreadRoot,
+            ];
+
+            const [timeline, threaded] = client.partitionThreadedEvents(events);
+
+            expect(timeline).toEqual([
+                eventReaction,
+                eventPollStartThreadRoot,
+            ]);
+
+            expect(threaded).toEqual([
+                eventMessageInThread,
+                withThreadId(eventReaction, eventPollStartThreadRoot.getId()),
+            ]);
+        });
+
+        it("copies post-thread in-timeline vote events onto both timelines", function() {
+            client.clientOpts = { experimentalThreadSupport: true };
+
+            const eventPollResponseReference = buildEventPollResponseReference();
+            const eventMessageInThread = buildEventMessageInThread();
+            const eventPollStartThreadRoot = buildEventPollStartThreadRoot();
+
+            const events = [
+                eventPollResponseReference,
+                eventMessageInThread,
+                eventPollStartThreadRoot,
+            ];
+
+            const [timeline, threaded] = client.partitionThreadedEvents(events);
+
+            expect(timeline).toEqual([
+                eventPollResponseReference,
+                eventPollStartThreadRoot,
+            ]);
+
+            expect(threaded).toEqual([
+                withThreadId(eventPollResponseReference, eventPollStartThreadRoot.getId()),
+                eventMessageInThread,
+            ]);
+        });
+
+        it("copies post-thread in-timeline reactions onto both timelines", function() {
+            client.clientOpts = { experimentalThreadSupport: true };
+
+            const eventReaction = buildEventReaction();
+            const eventMessageInThread = buildEventMessageInThread();
+            const eventPollStartThreadRoot = buildEventPollStartThreadRoot();
+
+            const events = [
+                eventReaction,
+                eventMessageInThread,
+                eventPollStartThreadRoot,
+            ];
+
+            const [timeline, threaded] = client.partitionThreadedEvents(events);
+
+            expect(timeline).toEqual([
+                eventReaction,
+                eventPollStartThreadRoot,
+            ]);
+
+            expect(threaded).toEqual([
+                withThreadId(eventReaction, eventPollStartThreadRoot.getId()),
+                eventMessageInThread,
+            ]);
+        });
+
+        it("sends room state events to the main timeline only", function() {
+            client.clientOpts = { experimentalThreadSupport: true };
+            // This is based on recording the events in a real room:
+
+            const eventMessageInThread = buildEventMessageInThread();
+            const eventPollResponseReference = buildEventPollResponseReference();
+            const eventPollStartThreadRoot = buildEventPollStartThreadRoot();
+            const eventRoomName = buildEventRoomName();
+            const eventEncryption = buildEventEncryption();
+            const eventGuestAccess = buildEventGuestAccess();
+            const eventHistoryVisibility = buildEventHistoryVisibility();
+            const eventJoinRules = buildEventJoinRules();
+            const eventPowerLevels = buildEventPowerLevels();
+            const eventMember = buildEventMember();
+            const eventCreate = buildEventCreate();
+
+            const events = [
+                eventMessageInThread,
+                eventPollResponseReference,
+                eventPollStartThreadRoot,
+                eventRoomName,
+                eventEncryption,
+                eventGuestAccess,
+                eventHistoryVisibility,
+                eventJoinRules,
+                eventPowerLevels,
+                eventMember,
+                eventCreate,
+            ];
+            const [timeline, threaded] = client.partitionThreadedEvents(events);
+
+            expect(timeline).toEqual([
+                // The message that was sent in a thread is missing
+                eventPollResponseReference,
+                eventPollStartThreadRoot,
+                eventRoomName,
+                eventEncryption,
+                eventGuestAccess,
+                eventHistoryVisibility,
+                eventJoinRules,
+                eventPowerLevels,
+                eventMember,
+                eventCreate,
+            ]);
+
+            // Thread should contain only stuff that happened in the thread -
+            // no thread root, and no room state events
+            expect(threaded).toEqual([
+                eventMessageInThread,
+                withThreadId(eventPollResponseReference, eventPollStartThreadRoot.getId()),
+            ]);
+        });
+    });
+});
+
+function withThreadId(event, newThreadId) {
+    const ret = event.toSnapshot();
+    ret.setThreadId(newThreadId);
+    return ret;
+}
+
+const buildEventMessageInThread = () => new MatrixEvent({
+    "age": 80098509,
+    "content": {
+        "algorithm": "m.megolm.v1.aes-sha2",
+        "ciphertext": "ENCRYPTEDSTUFF",
+        "device_id": "XISFUZSKHH",
+        "m.relates_to": {
+            "event_id": "$VLS2ojbPmxb6x8ECetn45hmND6cRDcjgv-j-to9m7Vo",
+            "m.in_reply_to": {
+                "event_id": "$VLS2ojbPmxb6x8ECetn45hmND6cRDcjgv-j-to9m7Vo",
+            },
+            "rel_type": "io.element.thread",
+        },
+        "sender_key": "i3N3CtG/CD2bGB8rA9fW6adLYSDvlUhf2iuU73L65Vg",
+        "session_id": "Ja11R/KG6ua0wdk8zAzognrxjio1Gm/RK2Gn6lFL804",
+    },
+    "event_id": "$W4chKIGYowtBblVLkRimeIg8TcdjETnxhDPGfi6NpDg",
+    "origin_server_ts": 1643815466378,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "type": "m.room.encrypted",
+    "unsigned": { "age": 80098509 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventPollResponseReference = () => new MatrixEvent({
+    "age": 80098509,
+    "content": {
+        "algorithm": "m.megolm.v1.aes-sha2",
+        "ciphertext": "ENCRYPTEDSTUFF",
+        "device_id": "XISFUZSKHH",
+        "m.relates_to": {
+            "event_id": "$VLS2ojbPmxb6x8ECetn45hmND6cRDcjgv-j-to9m7Vo",
+            "rel_type": "m.reference",
+        },
+        "sender_key": "i3N3CtG/CD2bGB8rA9fW6adLYSDvlUhf2iuU73L65Vg",
+        "session_id": "Ja11R/KG6ua0wdk8zAzognrxjio1Gm/RK2Gn6lFL804",
+    },
+    "event_id": "$91JvpezvsF0cKgav3g8W-uEVS4WkDHgxbJZvL3uMR1g",
+    "origin_server_ts": 1643815458650,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "type": "m.room.encrypted",
+    "unsigned": { "age": 80106237 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventReaction = () => new MatrixEvent({
+    "content": {
+        "m.relates_to": {
+            "event_id": "$VLS2ojbPmxb6x8ECetn45hmND6cRDcjgv-j-to9m7Vo",
+            "key": "🤗",
+            "rel_type": "m.annotation",
+        },
+    },
+    "origin_server_ts": 1643977249238,
+    "sender": "@andybalaam-test1:matrix.org",
+    "type": "m.reaction",
+    "unsigned": {
+        "age": 22598,
+        "transaction_id": "m1643977249073.16",
+    },
+    "event_id": "$86B2b-x3LgE4DlV4y24b7UHnt72LIA3rzjvMysTtAfA",
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+});
+
+const buildEventPollStartThreadRoot = () => new MatrixEvent({
+    "age": 80108647,
+    "content": {
+        "algorithm": "m.megolm.v1.aes-sha2",
+        "ciphertext": "ENCRYPTEDSTUFF",
+        "device_id": "XISFUZSKHH",
+        "sender_key": "i3N3CtG/CD2bGB8rA9fW6adLYSDvlUhf2iuU73L65Vg",
+        "session_id": "Ja11R/KG6ua0wdk8zAzognrxjio1Gm/RK2Gn6lFL804",
+    },
+    "event_id": "$VLS2ojbPmxb6x8ECetn45hmND6cRDcjgv-j-to9m7Vo",
+    "origin_server_ts": 1643815456240,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "type": "m.room.encrypted",
+    "unsigned": { "age": 80108647 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventRoomName = () => new MatrixEvent({
+    "age": 80123249,
+    "content": {
+        "name": "1 poll, 1 vote, 1 thread",
+    },
+    "event_id": "$QAdyNJtKnl1j7or2yMycbOCvb6bCgvHs5lg3ZMd5xWk",
+    "origin_server_ts": 1643815441638,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "state_key": "",
+    "type": "m.room.name",
+    "unsigned": { "age": 80123249 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventEncryption = () => new MatrixEvent({
+    "age": 80123383,
+    "content": {
+        "algorithm": "m.megolm.v1.aes-sha2",
+    },
+    "event_id": "$1hGykogKQkXbHw8bVuyE3BjHnFBEJBcUWnakd0ck2K0",
+    "origin_server_ts": 1643815441504,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "state_key": "",
+    "type": "m.room.encryption",
+    "unsigned": { "age": 80123383 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventGuestAccess = () => new MatrixEvent({
+    "age": 80123473,
+    "content": {
+        "guest_access": "can_join",
+    },
+    "event_id": "$4_2n-H6K9-0nPbnjjtIue2SU44tGJsnuTmi6UuSrh-U",
+    "origin_server_ts": 1643815441414,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "state_key": "",
+    "type": "m.room.guest_access",
+    "unsigned": { "age": 80123473 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventHistoryVisibility = () => new MatrixEvent({
+    "age": 80123556,
+    "content": {
+        "history_visibility": "shared",
+    },
+    "event_id": "$W6kp44CTnvciOiHSPyhp8dh4n2v1_9kclUPddeaQj0E",
+    "origin_server_ts": 1643815441331,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "state_key": "",
+    "type": "m.room.history_visibility",
+    "unsigned": { "age": 80123556 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventJoinRules = () => new MatrixEvent({
+    "age": 80123696,
+    "content": {
+        "join_rule": "invite",
+    },
+    "event_id": "$6JDDeDp7fEc0F6YnTWMruNcKWFltR3e9wk7wWDDJrAU",
+    "origin_server_ts": 1643815441191,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "state_key": "",
+    "type": "m.room.join_rules",
+    "unsigned": { "age": 80123696 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventPowerLevels = () => new MatrixEvent({
+    "age": 80124105,
+    "content": {
+        "ban": 50,
+        "events": {
+            "m.room.avatar": 50,
+            "m.room.canonical_alias": 50,
+            "m.room.encryption": 100,
+            "m.room.history_visibility": 100,
+            "m.room.name": 50,
+            "m.room.power_levels": 100,
+            "m.room.server_acl": 100,
+            "m.room.tombstone": 100,
+        },
+        "events_default": 0,
+        "historical": 100,
+        "invite": 0,
+        "kick": 50,
+        "redact": 50,
+        "state_default": 50,
+        "users": {
+            "@andybalaam-test1:matrix.org": 100,
+        },
+        "users_default": 0,
+    },
+    "event_id": "$XZY2YgQhXskpc7gmJJG3S0VmS9_QjjCUVeeFTfgfC2E",
+    "origin_server_ts": 1643815440782,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "state_key": "",
+    "type": "m.room.power_levels",
+    "unsigned": { "age": 80124105 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventMember = () => new MatrixEvent({
+    "age": 80125279,
+    "content": {
+        "avatar_url": "mxc://matrix.org/aNtbVcFfwotudypZcHsIcPOc",
+        "displayname": "andybalaam-test1",
+        "membership": "join",
+    },
+    "event_id": "$Ex5eVmMs_ti784mo8bgddynbwLvy6231lCycJr7Cl9M",
+    "origin_server_ts": 1643815439608,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "state_key": "@andybalaam-test1:matrix.org",
+    "type": "m.room.member",
+    "unsigned": { "age": 80125279 },
+    "user_id": "@andybalaam-test1:matrix.org",
+});
+
+const buildEventCreate = () => new MatrixEvent({
+    "age": 80126105,
+    "content": {
+        "creator": "@andybalaam-test1:matrix.org",
+        "room_version": "6",
+    },
+    "event_id": "$e7j2Gt37k5NPwB6lz2N3V9lO5pUdNK8Ai7i2FPEK-oI",
+    "origin_server_ts": 1643815438782,
+    "room_id": "!STrMRsukXHtqQdSeHa:matrix.org",
+    "sender": "@andybalaam-test1:matrix.org",
+    "state_key": "",
+    "type": "m.room.create",
+    "unsigned": { "age": 80126105 },
+    "user_id": "@andybalaam-test1:matrix.org",
 });
 
 function assertObjectContains(obj, expected) {

spec/test-utils.js

@@ -365,3 +365,5 @@ export function setHttpResponses(
             .respond(200, response.data);
     });
 }
+
+export const emitPromise = (e, k) => new Promise(r => e.once(k, r));

spec/unit/location.spec.ts

@@ -0,0 +1,56 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { makeLocationContent } from "../../src/content-helpers";
+import {
+    ASSET_NODE_TYPE,
+    ASSET_TYPE_SELF,
+    LOCATION_EVENT_TYPE,
+    TIMESTAMP_NODE_TYPE,
+} from "../../src/@types/location";
+import { TEXT_NODE_TYPE } from "../../src/@types/extensible_events";
+
+describe("Location", function() {
+    it("should create a valid location with defaults", function() {
+        const loc = makeLocationContent("txt", "geo:foo", 134235435);
+        expect(loc.body).toEqual("txt");
+        expect(loc.msgtype).toEqual("m.location");
+        expect(loc.geo_uri).toEqual("geo:foo");
+        expect(LOCATION_EVENT_TYPE.findIn(loc)).toEqual({
+            uri: "geo:foo",
+            description: undefined,
+        });
+        expect(ASSET_NODE_TYPE.findIn(loc)).toEqual({ type: ASSET_TYPE_SELF });
+        expect(TEXT_NODE_TYPE.findIn(loc)).toEqual("txt");
+        expect(TIMESTAMP_NODE_TYPE.findIn(loc)).toEqual(134235435);
+    });
+
+    it("should create a valid location with explicit properties", function() {
+        const loc = makeLocationContent(
+            "txxt", "geo:bar", 134235436, "desc", "m.something");
+
+        expect(loc.body).toEqual("txxt");
+        expect(loc.msgtype).toEqual("m.location");
+        expect(loc.geo_uri).toEqual("geo:bar");
+        expect(LOCATION_EVENT_TYPE.findIn(loc)).toEqual({
+            uri: "geo:bar",
+            description: "desc",
+        });
+        expect(ASSET_NODE_TYPE.findIn(loc)).toEqual({ type: "m.something" });
+        expect(TEXT_NODE_TYPE.findIn(loc)).toEqual("txxt");
+        expect(TIMESTAMP_NODE_TYPE.findIn(loc)).toEqual(134235436);
+    });
+});

spec/unit/matrix-client.spec.js

@@ -11,8 +11,9 @@ import {
     UNSTABLE_MSC3089_TREE_SUBTYPE,
 } from "../../src/@types/event";
 import { MEGOLM_ALGORITHM } from "../../src/crypto/olmlib";
-import { MatrixEvent } from "../../src/models/event";
+import { EventStatus, MatrixEvent } from "../../src/models/event";
 import { Preset } from "../../src/@types/partials";
+import * as testUtils from "../test-utils";
 
 jest.useFakeTimers();
 
@@ -713,6 +714,7 @@ describe("MatrixClient", function() {
     describe("guest rooms", function() {
         it("should only do /sync calls (without filter/pushrules)", function(done) {
             httpLookups = []; // no /pushrules or /filterw
+            httpLookups.push(CAPABILITIES_RESPONSE);
             httpLookups.push({
                 method: "GET",
                 path: "/sync",
@@ -867,4 +869,83 @@ describe("MatrixClient", function() {
             await client.redactEvent(roomId, eventId, txnId, { reason });
         });
     });
+
+    describe("cancelPendingEvent", () => {
+        const roomId = "!room:server";
+        const txnId = "m12345";
+
+        const mockRoom = {
+            getMyMembership: () => "join",
+            updatePendingEvent: (event, status) => event.setStatus(status),
+            currentState: {
+                getStateEvents: (eventType, stateKey) => {
+                    if (eventType === EventType.RoomCreate) {
+                        expect(stateKey).toEqual("");
+                        return new MatrixEvent({
+                            content: {
+                                [RoomCreateTypeField]: RoomType.Space,
+                            },
+                        });
+                    } else if (eventType === EventType.RoomEncryption) {
+                        expect(stateKey).toEqual("");
+                        return new MatrixEvent({ content: {} });
+                    } else {
+                        throw new Error("Unexpected event type or state key");
+                    }
+                },
+            },
+        };
+
+        let event;
+        beforeEach(async () => {
+            event = new MatrixEvent({
+                event_id: "~" + roomId + ":" + txnId,
+                user_id: client.credentials.userId,
+                sender: client.credentials.userId,
+                room_id: roomId,
+                origin_server_ts: new Date().getTime(),
+            });
+            event.setTxnId(txnId);
+
+            client.getRoom = (getRoomId) => {
+                expect(getRoomId).toEqual(roomId);
+                return mockRoom;
+            };
+            client.crypto = { // mock crypto
+                encryptEvent: (event, room) => new Promise(() => {}),
+            };
+        });
+
+        function assertCancelled() {
+            expect(event.status).toBe(EventStatus.CANCELLED);
+            expect(client.scheduler.removeEventFromQueue(event)).toBeFalsy();
+            expect(httpLookups.filter(h => h.path.includes("/send/")).length).toBe(0);
+        }
+
+        it("should cancel an event which is queued", () => {
+            event.setStatus(EventStatus.QUEUED);
+            client.scheduler.queueEvent(event);
+            client.cancelPendingEvent(event);
+            assertCancelled();
+        });
+
+        it("should cancel an event which is encrypting", async () => {
+            client.encryptAndSendEvent(null, event);
+            await testUtils.emitPromise(event, "Event.status");
+            client.cancelPendingEvent(event);
+            assertCancelled();
+        });
+
+        it("should cancel an event which is not sent", () => {
+            event.setStatus(EventStatus.NOT_SENT);
+            client.cancelPendingEvent(event);
+            assertCancelled();
+        });
+
+        it("should error when given any other event status", () => {
+            event.setStatus(EventStatus.SENDING);
+            expect(() => client.cancelPendingEvent(event)).toThrow("cannot cancel an event with status sending");
+            expect(event.status).toBe(EventStatus.SENDING);
+        });
+    });
 });

spec/unit/room-state.spec.js

@@ -120,7 +120,7 @@ describe("RoomState", function() {
         it("should return a single MatrixEvent if a state_key was specified",
         function() {
             const event = state.getStateEvents("m.room.member", userA);
-            expect(event.getContent()).toEqual({
+            expect(event.getContent()).toMatchObject({
                 membership: "join",
             });
         });

spec/unit/room.spec.js

@@ -1143,6 +1143,51 @@ describe("Room", function() {
                 ]));
                 expect(room.getEventReadUpTo(userB)).toEqual(events[2].getId());
             });
+
+            it("should prioritise the most recent event even if it is synthetic", () => {
+                const events = [
+                    utils.mkMessage({
+                        room: roomId, user: userA, msg: "1111",
+                        event: true,
+                    }),
+                    utils.mkMessage({
+                        room: roomId, user: userA, msg: "2222",
+                        event: true,
+                    }),
+                    utils.mkMessage({
+                        room: roomId, user: userA, msg: "3333",
+                        event: true,
+                    }),
+                ];
+
+                room.addLiveEvents(events);
+                const ts = 13787898424;
+
+                // check it initialises correctly
+                room.addReceipt(mkReceipt(roomId, [
+                    mkRecord(events[0].getId(), "m.read", userB, ts),
+                ]));
+                expect(room.getEventReadUpTo(userB)).toEqual(events[0].getId());
+
+                // 2>0, so it should move forward
+                room.addReceipt(mkReceipt(roomId, [
+                    mkRecord(events[2].getId(), "m.read", userB, ts),
+                ]), true);
+                expect(room.getEventReadUpTo(userB)).toEqual(events[2].getId());
+                expect(room.getReceiptsForEvent(events[2])).toEqual([
+                    { data: { ts }, type: "m.read", userId: userB },
+                ]);
+
+                // 1<2, so it should stay put
+                room.addReceipt(mkReceipt(roomId, [
+                    mkRecord(events[1].getId(), "m.read", userB, ts),
+                ]));
+                expect(room.getEventReadUpTo(userB)).toEqual(events[2].getId());
+                expect(room.getEventReadUpTo(userB, true)).toEqual(events[1].getId());
+                expect(room.getReceiptsForEvent(events[2])).toEqual([
+                    { data: { ts }, type: "m.read", userId: userB },
+                ]);
+            });
         });
 
         describe("getUsersReadUpTo", function() {
@@ -1461,7 +1506,7 @@ describe("Room", function() {
     describe("maySendMessage", function() {
         it("should return false if synced membership not join",
         function() {
-            const room = new Room(roomId, null, userA);
+            const room = new Room(roomId, { isRoomEncrypted: () => false }, userA);
             room.updateMyMembership("invite");
             expect(room.maySendMessage()).toEqual(false);
             room.updateMyMembership("leave");

src/@types/auth.ts

@@ -0,0 +1,29 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// disable lint because these are wire responses
+/* eslint-disable camelcase */
+
+/**
+ * Represents a response to the CSAPI `/refresh` endpoint.
+ */
+export interface IRefreshTokenResponse {
+    access_token: string;
+    expires_in_ms: number;
+    refresh_token: string;
+}
+
+/* eslint-enable camelcase */

src/@types/event.ts

@@ -92,6 +92,7 @@ export enum EventType {
 export enum RelationType {
     Annotation = "m.annotation",
     Replace = "m.replace",
+    Reference = "m.reference",
     /**
      * Note, "io.element.thread" is hardcoded
      * Should be replaced with "m.thread" once MSC3440 lands
@@ -177,6 +178,16 @@ export const UNSTABLE_ELEMENT_FUNCTIONAL_USERS = new UnstableValue(
     "io.element.functional_members",
     "io.element.functional_members");
 
+/**
+ * A type of message that affects visibility of a message,
+ * as per https://github.com/matrix-org/matrix-doc/pull/3531
+ *
+ * @experimental
+ */
+export const EVENT_VISIBILITY_CHANGE_TYPE = new UnstableValue(
+    "m.visibility",
+    "org.matrix.msc3531.visibility");
+
 export interface IEncryptedFile {
     url: string;
     mimetype?: string;

src/@types/location.ts

@@ -23,8 +23,12 @@ import { TEXT_NODE_TYPE } from "./extensible_events";
 export const LOCATION_EVENT_TYPE = new UnstableValue(
     "m.location", "org.matrix.msc3488.location");
 
+export const ASSET_NODE_TYPE = new UnstableValue("m.asset", "org.matrix.msc3488.asset");
+
 export const TIMESTAMP_NODE_TYPE = new UnstableValue("m.ts", "org.matrix.msc3488.ts");
 
+export const ASSET_TYPE_SELF = "m.self";
+
 /* From the spec at:
  * https://github.com/matrix-org/matrix-doc/blob/matthew/location/proposals/3488-location.md
 {
@@ -37,6 +41,9 @@ export const TIMESTAMP_NODE_TYPE = new UnstableValue("m.ts", "org.matrix.msc3488
             "uri": "geo:51.5008,0.1247;u=35",
             "description": "Matthew's whereabouts",
         },
+        "m.asset": {
+            "type": "m.self"
+        },
         "m.text": "Matthew was at geo:51.5008,0.1247;u=35 as of Sat Nov 13 18:50:58 2021",
         "m.ts": 1636829458432,
     }
@@ -52,6 +59,9 @@ export interface ILocationContent extends IContent {
         uri: string;
         description?: string;
     };
+    [ASSET_NODE_TYPE.name]: {
+        type: string;
+    };
     [TEXT_NODE_TYPE.name]: string;
     [TIMESTAMP_NODE_TYPE.name]: number;
 }

src/@types/polls.ts

@@ -1,68 +0,0 @@
-/*
-Copyright 2021 The Matrix.org Foundation C.I.C.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-import { UnstableValue } from "../NamespacedValue";
-import { IContent } from "../models/event";
-import { TEXT_NODE_TYPE } from "./extensible_events";
-
-export const POLL_START_EVENT_TYPE = new UnstableValue(
-    "m.poll.start", "org.matrix.msc3381.poll.start");
-
-export const POLL_RESPONSE_EVENT_TYPE = new UnstableValue(
-    "m.poll.response", "org.matrix.msc3381.poll.response");
-
-export const POLL_END_EVENT_TYPE = new UnstableValue(
-    "m.poll.end", "org.matrix.msc3381.poll.end");
-
-export const POLL_KIND_DISCLOSED = new UnstableValue(
-    "m.poll.disclosed", "org.matrix.msc3381.poll.disclosed");
-
-export const POLL_KIND_UNDISCLOSED = new UnstableValue(
-    "m.poll.undisclosed", "org.matrix.msc3381.poll.undisclosed");
-
-export interface IPollAnswer extends IContent {
-    id: string;
-    [TEXT_NODE_TYPE.name]: string;
-}
-
-export interface IPollContent extends IContent {
-    [POLL_START_EVENT_TYPE.name]: {
-        kind: string; // disclosed or undisclosed (untypeable for now)
-        question: {
-            [TEXT_NODE_TYPE.name]: string;
-        };
-        answers: IPollAnswer[];
-    };
-    [TEXT_NODE_TYPE.name]: string;
-}
-
-export interface IPollResponseContent extends IContent {
-    [POLL_RESPONSE_EVENT_TYPE.name]: {
-        answers: string[];
-    };
-    "m.relates_to": {
-        "event_id": string;
-        "rel_type": string;
-    };
-}
-
-export interface IPollEndContent extends IContent {
-    [POLL_END_EVENT_TYPE.name]: {};
-    "m.relates_to": {
-        "event_id": string;
-        "rel_type": string;
-    };
-}

src/@types/requests.ts

@@ -19,6 +19,7 @@ import { IContent, IEvent } from "../models/event";
 import { Preset, Visibility } from "./partials";
 import { SearchKey } from "./search";
 import { IRoomEventFilter } from "../filter";
+import { Direction } from "../models/event-timeline";
 
 // allow camelcase as these are things that go onto the wire
 /* eslint-disable camelcase */
@@ -144,6 +145,7 @@ export interface IRelationsRequestOpts {
     from?: string;
     to?: string;
     limit?: number;
+    direction?: Direction;
 }
 
 export interface IRelationsResponse {

src/client.ts

@@ -20,8 +20,9 @@ limitations under the License.
  */
 
 import { EventEmitter } from "events";
+import { EmoteEvent, IPartialEvent, MessageEvent, NoticeEvent } from "matrix-events-sdk";
 
-import { ISyncStateData, SyncApi } from "./sync";
+import { ISyncStateData, SyncApi, SyncState } from "./sync";
 import { EventStatus, IContent, IDecryptOptions, IEvent, MatrixEvent } from "./models/event";
 import { StubStore } from "./store/stub";
 import { createNewMatrixCall, MatrixCall } from "./webrtc/call";
@@ -51,6 +52,7 @@ import {
     PREFIX_MEDIA_R0,
     PREFIX_R0,
     PREFIX_UNSTABLE,
+    PREFIX_V1,
     retryNetworkOperation,
     UploadContentResponseType,
 } from "./http-api";
@@ -96,7 +98,6 @@ import {
     IRecoveryKey,
     ISecretStorageKeyInfo,
 } from "./crypto/api";
-import { SyncState } from "./sync";
 import { EventTimelineSet } from "./models/event-timeline-set";
 import { VerificationRequest } from "./crypto/verification/request/VerificationRequest";
 import { VerificationBase as Verification } from "./crypto/verification/Base";
@@ -153,6 +154,7 @@ import { IPusher, IPusherRequest, IPushRules, PushRuleAction, PushRuleKind, Rule
 import { IThreepid } from "./@types/threepids";
 import { CryptoStore } from "./crypto/store/base";
 import { MediaHandler } from "./webrtc/mediaHandler";
+import { IRefreshTokenResponse } from "./@types/auth";
 
 export type Store = IStore;
 export type SessionStore = WebStorageSessionStore;
@@ -804,7 +806,7 @@ export class MatrixClient extends EventEmitter {
     // TODO: This should expire: https://github.com/matrix-org/matrix-js-sdk/issues/1020
     protected serverVersionsPromise: Promise<IServerVersions>;
 
-    protected cachedCapabilities: {
+    public cachedCapabilities: {
         capabilities: ICapabilities;
         expiration: number;
     };
@@ -816,6 +818,7 @@ export class MatrixClient extends EventEmitter {
     protected exportedOlmDeviceToImport: IOlmDevice;
     protected txnCtr = 0;
     protected mediaHandler = new MediaHandler();
+    protected pendingEventEncryption = new Map<string, Promise<void>>();
 
     constructor(opts: IMatrixClientCreateOpts) {
         super();
@@ -870,7 +873,7 @@ export class MatrixClient extends EventEmitter {
 
         this.scheduler = opts.scheduler;
         if (this.scheduler) {
-            this.scheduler.setProcessFunction(async (eventToSend) => {
+            this.scheduler.setProcessFunction(async (eventToSend: MatrixEvent) => {
                 const room = this.getRoom(eventToSend.getRoomId());
                 if (eventToSend.status !== EventStatus.SENDING) {
                     this.updatePendingEventStatus(room, eventToSend, EventStatus.SENDING);
@@ -1001,7 +1004,7 @@ export class MatrixClient extends EventEmitter {
      * state change events.
      * @param {Object=} opts Options to apply when syncing.
      */
-    public async startClient(opts: IStartClientOpts): Promise<void> {
+    public async startClient(opts?: IStartClientOpts): Promise<void> {
         if (this.clientRunning) {
             // client is already running.
             return;
@@ -1041,9 +1044,7 @@ export class MatrixClient extends EventEmitter {
             this.syncApi.stop();
         }
 
-        if (!this.isGuest()) {
-            await this.getCapabilities(true);
-        }
+        await this.getCapabilities(true);
 
         // shallow-copy the opts dict before modifying and storing it
         this.clientOpts = Object.assign({}, opts) as IStoredClientOpts;
@@ -2576,8 +2577,10 @@ export class MatrixClient extends EventEmitter {
 
         return {
             algorithm,
+            /* eslint-disable camelcase */
             auth_data,
             recovery_key,
+            /* eslint-enable camelcase */
         };
     }
 
@@ -3399,15 +3402,18 @@ export class MatrixClient extends EventEmitter {
      * Cancel a queued or unsent event.
      *
      * @param {MatrixEvent} event   Event to cancel
-     * @throws Error if the event is not in QUEUED or NOT_SENT state
+     * @throws Error if the event is not in QUEUED, NOT_SENT or ENCRYPTING state
      */
     public cancelPendingEvent(event: MatrixEvent) {
-        if ([EventStatus.QUEUED, EventStatus.NOT_SENT].indexOf(event.status) < 0) {
+        if (![EventStatus.QUEUED, EventStatus.NOT_SENT, EventStatus.ENCRYPTING].includes(event.status)) {
             throw new Error("cannot cancel an event with status " + event.status);
         }
 
-        // first tell the scheduler to forget about it, if it's queued
-        if (this.scheduler) {
+        // if the event is currently being encrypted then
+        if (event.status === EventStatus.ENCRYPTING) {
+            this.pendingEventEncryption.delete(event.getId());
+        } else if (this.scheduler && event.status === EventStatus.QUEUED) {
+            // tell the scheduler to forget about it, if it's queued
             this.scheduler.removeEventFromQueue(event);
         }
 
@@ -3582,6 +3588,25 @@ export class MatrixClient extends EventEmitter {
             eventType = threadId;
             threadId = null;
         }
+
+        // If we expect that an event is part of a thread but is missing the relation
+        // we need to add it manually, as well as the reply fallback
+        if (threadId && !content["m.relates_to"]?.rel_type) {
+            content["m.relates_to"] = {
+                ...content["m.relates_to"],
+                "rel_type": RelationType.Thread,
+                "event_id": threadId,
+            };
+            const thread = this.getRoom(roomId)?.threads.get(threadId);
+            if (thread) {
+                content["m.relates_to"]["m.in_reply_to"] = {
+                    "event_id": thread.lastReply((ev: MatrixEvent) => {
+                        return ev.isThreadRelation && !ev.status;
+                    }),
+                };
+            }
+        }
+
         return this.sendCompleteEvent(roomId, threadId, { type: eventType, content }, txnId as string, callback);
     }
 
@@ -3625,6 +3650,7 @@ export class MatrixClient extends EventEmitter {
         const thread = room?.threads.get(threadId);
         if (thread) {
             localEvent.setThread(thread);
+            localEvent.setThreadId(thread.id);
         }
 
         // if this is a relation or redaction of an event
@@ -3642,12 +3668,12 @@ export class MatrixClient extends EventEmitter {
         const type = localEvent.getType();
         logger.log(`sendEvent of type ${type} in ${roomId} with txnId ${txnId}`);
 
-        localEvent.setTxnId(txnId as string);
+        localEvent.setTxnId(txnId);
         localEvent.setStatus(EventStatus.SENDING);
 
         // add this event immediately to the local store as 'sending'.
         if (room) {
-            room.addPendingEvent(localEvent, txnId as string);
+            room.addPendingEvent(localEvent, txnId);
         }
 
         // addPendingEvent can change the state to NOT_SENT if it believes
@@ -3669,16 +3695,26 @@ export class MatrixClient extends EventEmitter {
      * @private
      */
     private encryptAndSendEvent(room: Room, event: MatrixEvent, callback?: Callback): Promise<ISendEventResponse> {
+        let cancelled = false;
         // Add an extra Promise.resolve() to turn synchronous exceptions into promise rejections,
         // so that we can handle synchronous and asynchronous exceptions with the
         // same code path.
         return Promise.resolve().then(() => {
             const encryptionPromise = this.encryptEventIfNeeded(event, room);
-            if (!encryptionPromise) return null;
+            if (!encryptionPromise) return null; // doesn't need encryption
 
+            this.pendingEventEncryption.set(event.getId(), encryptionPromise);
             this.updatePendingEventStatus(room, event, EventStatus.ENCRYPTING);
-            return encryptionPromise.then(() => this.updatePendingEventStatus(room, event, EventStatus.SENDING));
+            return encryptionPromise.then(() => {
+                if (!this.pendingEventEncryption.has(event.getId())) {
+                    // cancelled via MatrixClient::cancelPendingEvent
+                    cancelled = true;
+                    return;
+                }
+                this.updatePendingEventStatus(room, event, EventStatus.SENDING);
+            });
         }).then(() => {
+            if (cancelled) return {} as ISendEventResponse;
             let promise: Promise<ISendEventResponse>;
             if (this.scheduler) {
                 // if this returns a promise then the scheduler has control now and will
@@ -3922,11 +3958,51 @@ export class MatrixClient extends EventEmitter {
             callback = txnId as any as Callback; // for legacy
             txnId = undefined;
         }
+
+        // Populate all outbound events with Extensible Events metadata to ensure there's a
+        // reasonably large pool of messages to parse.
+        let eventType: string = EventType.RoomMessage;
+        let sendContent: IContent = content as IContent;
+        const makeContentExtensible = (content: IContent = {}, recurse = true): IPartialEvent<object> => {
+            let newEvent: IPartialEvent<object> = null;
+
+            if (content['msgtype'] === MsgType.Text) {
+                newEvent = MessageEvent.from(content['body'], content['formatted_body']).serialize();
+            } else if (content['msgtype'] === MsgType.Emote) {
+                newEvent = EmoteEvent.from(content['body'], content['formatted_body']).serialize();
+            } else if (content['msgtype'] === MsgType.Notice) {
+                newEvent = NoticeEvent.from(content['body'], content['formatted_body']).serialize();
+            }
+
+            if (newEvent && content['m.new_content'] && recurse) {
+                const newContent = makeContentExtensible(content['m.new_content'], false);
+                if (newContent) {
+                    newEvent.content['m.new_content'] = newContent.content;
+                }
+            }
+
+            if (newEvent) {
+                // copy over all other fields we don't know about
+                for (const [k, v] of Object.entries(content)) {
+                    if (!newEvent.content.hasOwnProperty(k)) {
+                        newEvent.content[k] = v;
+                    }
+                }
+            }
+
+            return newEvent;
+        };
+        const result = makeContentExtensible(sendContent);
+        if (result) {
+            eventType = result.type;
+            sendContent = result.content;
+        }
+
         return this.sendEvent(
             roomId,
             threadId as (string | null),
-            EventType.RoomMessage,
-            content as IContent,
+            eventType,
+            sendContent,
             txnId as string,
             callback,
         );
@@ -4151,6 +4227,7 @@ export class MatrixClient extends EventEmitter {
             info: info,
             body: text,
         };
+
         return this.sendEvent(roomId, threadId, EventType.Sticker, content, undefined, callback);
     }
 
@@ -4994,7 +5071,7 @@ export class MatrixClient extends EventEmitter {
                     limit,
                     Direction.Backward,
                 );
-            }).then((res: IMessagesResponse) => {
+            }).then(async (res: IMessagesResponse) => {
                 const matrixEvents = res.chunk.map(this.getEventMapper());
                 if (res.state) {
                     const stateEvents = res.state.map(this.getEventMapper());
@@ -5004,7 +5081,7 @@ export class MatrixClient extends EventEmitter {
                 const [timelineEvents, threadedEvents] = this.partitionThreadedEvents(matrixEvents);
 
                 room.addEventsToTimeline(timelineEvents, true, room.getLiveTimeline());
-                this.processThreadEvents(room, threadedEvents);
+                await this.processThreadEvents(room, threadedEvents);
 
                 room.oldState.paginationToken = res.end;
                 if (res.chunk.length === 0) {
@@ -5082,7 +5159,7 @@ export class MatrixClient extends EventEmitter {
 
         // TODO: we should implement a backoff (as per scrollback()) to deal more
         // nicely with HTTP errors.
-        const promise = this.http.authedRequest<any>(undefined, Method.Get, path, params).then((res) => { // TODO types
+        const promise = this.http.authedRequest<any>(undefined, Method.Get, path, params).then(async (res) => { // TODO types
             if (!res.event) {
                 throw new Error("'event' not in '/context' result - homeserver too old?");
             }
@@ -5115,7 +5192,7 @@ export class MatrixClient extends EventEmitter {
             const [timelineEvents, threadedEvents] = this.partitionThreadedEvents(matrixEvents);
 
             timelineSet.addEventsToTimeline(timelineEvents, true, timeline, res.start);
-            this.processThreadEvents(timelineSet.room, threadedEvents);
+            await this.processThreadEvents(timelineSet.room, threadedEvents);
 
             // there is no guarantee that the event ended up in "timeline" (we
             // might have switched to a neighbouring timeline) - so check the
@@ -5230,7 +5307,7 @@ export class MatrixClient extends EventEmitter {
 
             promise = this.http.authedRequest<any>( // TODO types
                 undefined, Method.Get, path, params, undefined,
-            ).then((res) => {
+            ).then(async (res) => {
                 const token = res.next_token;
                 const matrixEvents = [];
 
@@ -5248,7 +5325,7 @@ export class MatrixClient extends EventEmitter {
 
                 const timelineSet = eventTimeline.getTimelineSet();
                 timelineSet.addEventsToTimeline(timelineEvents, backwards, eventTimeline, token);
-                this.processThreadEvents(timelineSet.room, threadedEvents);
+                await this.processThreadEvents(timelineSet.room, threadedEvents);
 
                 // if we've hit the end of the timeline, we need to stop trying to
                 // paginate. We need to keep the 'forwards' token though, to make sure
@@ -5273,7 +5350,7 @@ export class MatrixClient extends EventEmitter {
                 opts.limit,
                 dir,
                 eventTimeline.getFilter(),
-            ).then((res) => {
+            ).then(async (res) => {
                 if (res.state) {
                     const roomState = eventTimeline.getState(dir);
                     const stateEvents = res.state.map(this.getEventMapper());
@@ -5286,7 +5363,7 @@ export class MatrixClient extends EventEmitter {
 
                 eventTimeline.getTimelineSet()
                     .addEventsToTimeline(timelineEvents, backwards, eventTimeline, token);
-                this.processThreadEvents(room, threadedEvents);
+                await this.processThreadEvents(room, threadedEvents);
 
                 // if we've hit the end of the timeline, we need to stop trying to
                 // paginate. We need to keep the 'forwards' token though, to make sure
@@ -6537,6 +6614,14 @@ export class MatrixClient extends EventEmitter {
         return this.http.opts.accessToken || null;
     }
 
+    /**
+     * Set the access token associated with this account.
+     * @param {string} token The new access token.
+     */
+    public setAccessToken(token: string) {
+        this.http.opts.accessToken = token;
+    }
+
     /**
      * @return {boolean} true if there is a valid access_token for this client.
      */
@@ -6557,13 +6642,18 @@ export class MatrixClient extends EventEmitter {
      * Check whether a username is available prior to registration. An error response
      * indicates an invalid/unavailable username.
      * @param {string} username The username to check the availability of.
-     * @return {Promise} Resolves: to `true`.
+     * @return {Promise} Resolves: to boolean of whether the username is available.
      */
-    public isUsernameAvailable(username: string): Promise<true> {
+    public isUsernameAvailable(username: string): Promise<boolean> {
         return this.http.authedRequest<{ available: true }>(
-            undefined, Method.Get, '/register/available', { username: username },
+            undefined, Method.Get, '/register/available', { username },
         ).then((response) => {
             return response.available;
+        }).catch(response => {
+            if (response.errcode === "M_USER_IN_USE") {
+                return false;
+            }
+            return Promise.reject(response);
         });
     }
 
@@ -6608,6 +6698,7 @@ export class MatrixClient extends EventEmitter {
 
         const params: any = {
             auth: auth,
+            refresh_token: true, // always ask for a refresh token - does nothing if unsupported
         };
         if (username !== undefined && username !== null) {
             params.username = username;
@@ -6685,6 +6776,31 @@ export class MatrixClient extends EventEmitter {
         return this.http.request(callback, Method.Post, "/register", params, data);
     }
 
+    /**
+     * Refreshes an access token using a provided refresh token. The refresh token
+     * must be valid for the current access token known to the client instance.
+     *
+     * Note that this function will not cause a logout if the token is deemed
+     * unknown by the server - the caller is responsible for managing logout
+     * actions on error.
+     * @param {string} refreshToken The refresh token.
+     * @return {Promise<IRefreshTokenResponse>} Resolves to the new token.
+     * @return {module:http-api.MatrixError} Rejects with an error response.
+     */
+    public refreshToken(refreshToken: string): Promise<IRefreshTokenResponse> {
+        return this.http.authedRequest(
+            undefined,
+            Method.Post,
+            "/refresh",
+            undefined,
+            { refresh_token: refreshToken },
+            {
+                prefix: PREFIX_V1,
+                inhibitLogoutEmit: true, // we don't want to cause logout loops
+            },
+        );
+    }
+
     /**
      * @param {module:client.callback} callback Optional.
      * @return {Promise} Resolves: TODO
@@ -6798,7 +6914,17 @@ export class MatrixClient extends EventEmitter {
      * @param {module:client.callback} callback Optional.
      * @return {Promise} Resolves: On success, the empty object
      */
-    public logout(callback?: Callback): Promise<{}> {
+    public async logout(callback?: Callback): Promise<{}> {
+        if (this.crypto?.backupManager?.getKeyBackupEnabled()) {
+            try {
+                while (await this.crypto.backupManager.backupPendingKeys(200) > 0);
+            } catch (err) {
+                logger.error(
+                    "Key backup request failed when logging out. Some keys may be missing from backup",
+                    err,
+                );
+            }
+        }
         return this.http.authedRequest(
             callback, Method.Post, '/logout',
         );
@@ -8502,12 +8628,21 @@ export class MatrixClient extends EventEmitter {
             $roomId: roomId,
         });
 
-        return this.http.authedRequest<IRoomHierarchy>(undefined, Method.Get, path, {
+        const queryParams: Record<string, string | string[]> = {
             suggested_only: String(suggestedOnly),
-            max_depth: maxDepth?.toString(),
-            from: fromToken,
-            limit: limit?.toString(),
-        }, undefined, {
+        };
+
+        if (limit !== undefined) {
+            queryParams["limit"] = limit.toString();
+        }
+        if (maxDepth !== undefined) {
+            queryParams["max_depth"] = maxDepth.toString();
+        }
+        if (fromToken !== undefined) {
+            queryParams["from"] = fromToken;
+        }
+
+        return this.http.authedRequest<IRoomHierarchy>(undefined, Method.Get, path, queryParams, undefined, {
             prefix: "/_matrix/client/unstable/org.matrix.msc2946",
         }).catch(e => {
             if (e.errcode === "M_UNRECOGNIZED") {
@@ -8982,37 +9117,90 @@ export class MatrixClient extends EventEmitter {
         });
     }
 
+    /**
+     * Given some events, find the IDs of all the thread roots that are
+     * referred to by them.
+     */
+    private findThreadRoots(events: MatrixEvent[]): Set<string> {
+        const threadRoots = new Set<string>();
+        for (const event of events) {
+            if (event.isThreadRelation) {
+                threadRoots.add(event.relationEventId);
+            }
+        }
+        return threadRoots;
+    }
+
+    private eventShouldLiveIn(event: MatrixEvent, room: Room, events: MatrixEvent[], roots: Set<string>): {
+        shouldLiveInRoom: boolean;
+        shouldLiveInThread: boolean;
+        threadId?: string;
+    } {
+        // A thread relation is always only shown in a thread
+        if (event.isThreadRelation) {
+            return {
+                shouldLiveInRoom: false,
+                shouldLiveInThread: true,
+                threadId: event.relationEventId,
+            };
+        }
+
+        const parentEventId = event.getAssociatedId();
+        const parentEvent = room?.findEventById(parentEventId) || events.find((mxEv: MatrixEvent) => (
+            mxEv.getId() === parentEventId
+        ));
+
+        // A reaction targetting the thread root needs to be routed to both the
+        // the main timeline and the associated thread
+        const targetingThreadRoot = parentEvent?.isThreadRoot || roots.has(event.relationEventId);
+        if (targetingThreadRoot) {
+            return {
+                shouldLiveInRoom: true,
+                shouldLiveInThread: true,
+                threadId: event.relationEventId,
+            };
+        }
+
+        // If the parent event also has an associated ID we want to re-run the
+        // computation for that parent event.
+        // In the case of the redaction of a reaction that targets a root event
+        // we want that redaction to be pushed to both timeline
+        if (parentEvent?.getAssociatedId()) {
+            return this.eventShouldLiveIn(parentEvent, room, events, roots);
+        } else {
+            // We've exhausted all scenarios, can safely assume that this event
+            // should live in the room timeline
+            return {
+                shouldLiveInRoom: true,
+                shouldLiveInThread: false,
+            };
+        }
+    }
+
     public partitionThreadedEvents(events: MatrixEvent[]): [MatrixEvent[], MatrixEvent[]] {
         // Indices to the events array, for readibility
         const ROOM = 0;
         const THREAD = 1;
-        const threadRoots = new Set<string>();
         if (this.supportsExperimentalThreads()) {
+            const threadRoots = this.findThreadRoots(events);
             return events.reduce((memo, event: MatrixEvent) => {
                 const room = this.getRoom(event.getRoomId());
-                // An event should live in the thread timeline if
-                // - It's a reply in thread event
-                // - It's related to a reply in thread event
-                let shouldLiveInThreadTimeline = event.isThreadRelation;
-                if (shouldLiveInThreadTimeline) {
-                    threadRoots.add(event.relationEventId);
-                } else {
-                    const parentEventId = event.parentEventId;
-                    const parentEvent = room?.findEventById(parentEventId) || events.find((mxEv: MatrixEvent) => {
-                        return mxEv.getId() === parentEventId;
-                    });
-                    shouldLiveInThreadTimeline = parentEvent?.isThreadRelation;
 
-                    // Copy all the reactions and annotations to the root event
-                    // to the thread timeline. They will end up living in both
-                    // timelines at the same time
-                    const targetingThreadRoot = parentEvent?.isThreadRoot || threadRoots.has(event.relationEventId);
-                    if (targetingThreadRoot && !event.isThreadRelation && event.relationEventId) {
-                        memo[THREAD].push(event);
-                    }
+                const {
+                    shouldLiveInRoom,
+                    shouldLiveInThread,
+                    threadId,
+                } = this.eventShouldLiveIn(event, room, events, threadRoots);
+
+                if (shouldLiveInRoom) {
+                    memo[ROOM].push(event);
                 }
-                const targetTimeline = shouldLiveInThreadTimeline ? THREAD : ROOM;
-                memo[targetTimeline].push(event);
+
+                if (shouldLiveInThread) {
+                    event.setThreadId(threadId);
+                    memo[THREAD].push(event);
+                }
+
                 return memo;
             }, [[], []]);
         } else {
@@ -9028,12 +9216,11 @@ export class MatrixClient extends EventEmitter {
     /**
      * @experimental
      */
-    public processThreadEvents(room: Room, threadedEvents: MatrixEvent[]): void {
-        threadedEvents
-            .sort((a, b) => a.getTs() - b.getTs())
-            .forEach(event => {
-                room.addThreadedEvent(event);
-            });
+    public async processThreadEvents(room: Room, threadedEvents: MatrixEvent[]): Promise<void> {
+        threadedEvents.sort((a, b) => a.getTs() - b.getTs());
+        for (const event of threadedEvents) {
+            await room.addThreadedEvent(event);
+        }
     }
 
     /**

src/content-helpers.ts

@@ -1,6 +1,5 @@
 /*
-Copyright 2018 New Vector Ltd
-Copyright 2018 - 2021 The Matrix.org Foundation C.I.C.
+Copyright 2018 - 2022 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -19,8 +18,13 @@ limitations under the License.
 
 import { MsgType } from "./@types/event";
 import { TEXT_NODE_TYPE } from "./@types/extensible_events";
-import { ILocationContent, LOCATION_EVENT_TYPE, TIMESTAMP_NODE_TYPE } from "./@types/location";
-import { IPollContent, POLL_START_EVENT_TYPE } from "./@types/polls";
+import {
+    ASSET_NODE_TYPE,
+    ASSET_TYPE_SELF,
+    ILocationContent,
+    LOCATION_EVENT_TYPE,
+    TIMESTAMP_NODE_TYPE,
+} from "./@types/location";
 
 /**
  * Generates the content for a HTML Message event
@@ -103,35 +107,6 @@ export function makeEmoteMessage(body: string) {
     };
 }
 
-/**
- * Generates the content for a Poll Start event
- * @param question the poll question
- * @param answers the possible answers
- * @param kind whether the poll is disclosed or undisclosed. Allowed values are
- *             "m.poll.disclosed" or "m.poll.undisclosed", or the unstable equivalents
- */
-export function makePollContent(
-    question: string,
-    answers: string[],
-    kind: string,
-): IPollContent {
-    question = question.trim();
-    answers = answers.map(a => a.trim()).filter(a => !!a);
-    return {
-        [TEXT_NODE_TYPE.name]:
-            `${question}\n${answers.map((a, i) => `${i + 1}. ${a}`).join('\n')}`,
-        [POLL_START_EVENT_TYPE.name]: {
-            kind: kind,
-            question: {
-                [TEXT_NODE_TYPE.name]: question,
-            },
-            answers: answers.map(
-                (a, i) => ({ id: `${i}-${a}`, [TEXT_NODE_TYPE.name]: a }),
-            ),
-        },
-    };
-}
-
 /**
  * Generates the content for a Location event
  * @param text a text for of our location
@@ -139,12 +114,14 @@ export function makePollContent(
  * @param ts the timestamp when the location was correct (milliseconds since
  *           the UNIX epoch)
  * @param description the (optional) label for this location on the map
+ * @param asset_type the (optional) asset type of this location e.g. "m.self"
  */
 export function makeLocationContent(
     text: string,
     uri: string,
     ts: number,
     description?: string,
+    assetType?: string,
 ): ILocationContent {
     return {
         "body": text,
@@ -154,8 +131,11 @@ export function makeLocationContent(
             uri,
             description,
         },
-        [TIMESTAMP_NODE_TYPE.name]: ts,
+        [ASSET_NODE_TYPE.name]: {
+            type: assetType ?? ASSET_TYPE_SELF,
+        },
         [TEXT_NODE_TYPE.name]: text,
+        [TIMESTAMP_NODE_TYPE.name]: ts,
         // TODO: MSC1767 fallbacks m.image thumbnail
     };
 }

src/crypto/backup.ts

@@ -313,11 +313,24 @@ export class BackupManager {
             return ret;
         }
 
-        const trustedPubkey = this.baseApis.crypto.sessionStore.getLocalTrustedBackupPubKey();
+        const privKey = await this.baseApis.crypto.getSessionBackupPrivateKey();
+        if (privKey) {
+            let algorithm;
+            try {
+                algorithm = await BackupManager.makeAlgorithm(backupInfo, async () => privKey);
 
-        if ("public_key" in backupInfo.auth_data && backupInfo.auth_data.public_key === trustedPubkey) {
-            logger.info("Backup public key " + trustedPubkey + " is trusted locally");
-            ret.trusted_locally = true;
+                if (await algorithm.keyMatches(privKey)) {
+                    logger.info("Backup is trusted locally");
+                    ret.trusted_locally = true;
+                }
+            } catch {
+                // do nothing -- if we have an error, then we don't mark it as
+                // locally trusted
+            } finally {
+                if (algorithm) {
+                    algorithm.free();
+                }
+            }
         }
 
         const mySigs = backupInfo.auth_data.signatures[this.baseApis.getUserId()] || {};
@@ -467,7 +480,7 @@ export class BackupManager {
      * @param {integer} limit Maximum number of keys to back up
      * @returns {integer} Number of sessions backed up
      */
-    private async backupPendingKeys(limit: number): Promise<number> {
+    public async backupPendingKeys(limit: number): Promise<number> {
         const sessions = await this.baseApis.crypto.cryptoStore.getSessionsNeedingBackup(limit);
         if (!sessions.length) {
             return 0;

src/crypto/index.ts

@@ -2728,7 +2728,6 @@ export class Crypto extends EventEmitter {
         }
     }
 
-    /* eslint-disable valid-jsdoc */    //https://github.com/eslint/eslint/issues/7307
     /**
      * Encrypt an event according to the configuration of the room.
      *
@@ -2739,8 +2738,6 @@ export class Crypto extends EventEmitter {
      * @return {Promise?} Promise which resolves when the event has been
      *     encrypted, or null if nothing was needed
      */
-    /* eslint-enable valid-jsdoc */
-    // TODO this return type lies
     public async encryptEvent(event: MatrixEvent, room: Room): Promise<void> {
         if (!room) {
             throw new Error("Cannot send encrypted messages in unknown rooms");

src/event-mapper.ts

@@ -41,7 +41,7 @@ export function eventMapperFor(client: MatrixClient, options: MapperOpts): Event
             }
         }
         if (!preventReEmit) {
-            client.reEmitter.reEmit(event, ["Event.replaced"]);
+            client.reEmitter.reEmit(event, ["Event.replaced", "Event.visibilityChange"]);
         }
         return event;
     }

src/filter-component.ts

@@ -14,6 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { RelationType } from "./@types/event";
 import { UNSTABLE_FILTER_RELATION_SENDERS, UNSTABLE_FILTER_RELATION_TYPES } from "./filter";
 import { MatrixEvent } from "./models/event";
 
@@ -47,6 +48,7 @@ export interface IFilterComponent {
     not_senders?: string[];
     contains_url?: boolean;
     limit?: number;
+    [UNSTABLE_FILTER_RELATION_TYPES.name]?: Array<RelationType | string>;
 }
 /* eslint-enable camelcase */
 
@@ -62,7 +64,7 @@ export interface IFilterComponent {
  * @param {Object} filterJson the definition of this filter JSON, e.g. { 'contains_url': true }
  */
 export class FilterComponent {
-    constructor(private filterJson: IFilterComponent) {}
+    constructor(private filterJson: IFilterComponent, public readonly userId?: string) {}
 
     /**
      * Checks with the filter component matches the given event
@@ -70,11 +72,24 @@ export class FilterComponent {
      * @return {boolean} true if the event matches the filter
      */
     public check(event: MatrixEvent): boolean {
+        const bundledRelationships = event.getUnsigned()?.["m.relations"] || {};
+        const relations: Array<string | RelationType> = Object.keys(bundledRelationships);
+        // Relation senders allows in theory a look-up of any senders
+        // however clients can only know about the current user participation status
+        // as sending a whole list of participants could be proven problematic in terms
+        // of performance
+        // This should be improved when bundled relationships solve that problem
+        const relationSenders = [];
+        if (this.userId && relations?.[RelationType.Thread]?.current_user_participated) {
+            relationSenders.push(this.userId);
+        }
         return this.checkFields(
             event.getRoomId(),
             event.getSender(),
             event.getType(),
             event.getContent() ? event.getContent().url !== undefined : false,
+            relations,
+            relationSenders,
         );
     }
 
@@ -101,9 +116,18 @@ export class FilterComponent {
      * @param {String} sender        the sender of the event being checked
      * @param {String} eventType     the type of the event being checked
      * @param {boolean} containsUrl  whether the event contains a content.url field
+     * @param {boolean} relationTypes  whether has aggregated relation of the given type
+     * @param {boolean} relationSenders whether one of the relation is sent by the user listed
      * @return {boolean} true if the event fields match the filter
      */
-    private checkFields(roomId: string, sender: string, eventType: string, containsUrl: boolean): boolean {
+    private checkFields(
+        roomId: string,
+        sender: string,
+        eventType: string,
+        containsUrl: boolean,
+        relationTypes: Array<RelationType | string>,
+        relationSenders: string[],
+    ): boolean {
         const literalKeys = {
             "rooms": function(v: string): boolean {
                 return roomId === v;
@@ -136,15 +160,35 @@ export class FilterComponent {
             return false;
         }
 
+        const relationTypesFilter = this.filterJson[UNSTABLE_FILTER_RELATION_TYPES.name];
+        if (relationTypesFilter !== undefined) {
+            if (!this.arrayMatchesFilter(relationTypesFilter, relationTypes)) {
+                return false;
+            }
+        }
+
+        const relationSendersFilter = this.filterJson[UNSTABLE_FILTER_RELATION_SENDERS.name];
+        if (relationSendersFilter !== undefined) {
+            if (!this.arrayMatchesFilter(relationSendersFilter, relationSenders)) {
+                return false;
+            }
+        }
+
         return true;
     }
 
+    private arrayMatchesFilter(filter: any[], values: any[]): boolean {
+        return values.length > 0 && values.every(value => {
+            return filter.includes(value);
+        });
+    }
+
     /**
      * Filters a list of events down to those which match this filter component
      * @param {MatrixEvent[]} events  Events to be checked against the filter component
      * @return {MatrixEvent[]} events which matched the filter component
      */
-    filter(events: MatrixEvent[]): MatrixEvent[] {
+    public filter(events: MatrixEvent[]): MatrixEvent[] {
         return events.filter(this.check, this);
     }
 
@@ -153,7 +197,7 @@ export class FilterComponent {
      * 10 if none is otherwise specified. Cargo-culted from Synapse.
      * @return {Number} the limit for this filter component.
      */
-    limit(): number {
+    public limit(): number {
         return this.filterJson.limit !== undefined ? this.filterJson.limit : 10;
     }
 }

src/filter.ts

@@ -185,8 +185,8 @@ export class Filter {
             }
         }
 
-        this.roomFilter = new FilterComponent(roomFilterFields);
-        this.roomTimelineFilter = new FilterComponent(roomFilterJson?.timeline || {});
+        this.roomFilter = new FilterComponent(roomFilterFields, this.userId);
+        this.roomTimelineFilter = new FilterComponent(roomFilterJson?.timeline || {}, this.userId);
 
         // don't bother porting this from synapse yet:
         // this._room_state_filter =

src/http-api.ts

@@ -111,6 +111,12 @@ interface IRequestOpts<T> {
     json?: boolean; // defaults to true
     qsStringifyOptions?: CoreOptions["qsStringifyOptions"];
     bodyParser?(body: string): T;
+
+    // Set to true to prevent the request function from emitting
+    // a Session.logged_out event. This is intended for use on
+    // endpoints where M_UNKNOWN_TOKEN is a valid/notable error
+    // response, such as with token refreshes.
+    inhibitLogoutEmit?: boolean;
 }
 
 export interface IUpload {
@@ -437,10 +443,20 @@ export class MatrixHttpApi {
                 queryParams.filename = fileName;
             }
 
+            const headers: Record<string, string> = { "Content-Type": contentType };
+
+            // authedRequest uses `request` which is no longer maintained.
+            // `request` has a bug where if the body is zero bytes then you get an error: `Argument error, options.body`.
+            // See https://github.com/request/request/issues/920
+            // if body looks like a byte array and empty then set the Content-Length explicitly as a workaround:
+            if ((body as unknown as ArrayLike<number>).length === 0) {
+                headers["Content-Length"] = "0";
+            }
+
             promise = this.authedRequest(
                 opts.callback, Method.Post, "/upload", queryParams, body, {
                     prefix: "/_matrix/media/r0",
-                    headers: { "Content-Type": contentType },
+                    headers,
                     json: false,
                     bodyParser,
                 },
@@ -508,7 +524,7 @@ export class MatrixHttpApi {
         if (method === Method.Get) {
             opts.qs = params;
         } else if (typeof params === "object") {
-            opts.json = !!params; // XXX: this feels strange
+            opts.json = params;
         }
 
         if (accessToken) {
@@ -586,7 +602,7 @@ export class MatrixHttpApi {
         const requestPromise = this.request<T, O>(callback, method, path, queryParams, data, requestOpts);
 
         requestPromise.catch((err: MatrixError) => {
-            if (err.errcode == 'M_UNKNOWN_TOKEN') {
+            if (err.errcode == 'M_UNKNOWN_TOKEN' && !requestOpts?.inhibitLogoutEmit) {
                 this.eventEmitter.emit("Session.logged_out", err);
             } else if (err.errcode == 'M_CONSENT_NOT_GIVEN') {
                 this.eventEmitter.emit(

src/models/MSC3089Branch.ts

@@ -20,6 +20,7 @@ import { IContent, MatrixEvent } from "./event";
 import { MSC3089TreeSpace } from "./MSC3089TreeSpace";
 import { EventTimeline } from "./event-timeline";
 import { FileType } from "../http-api";
+import type { ISendEventResponse } from "..";
 
 /**
  * Represents a [MSC3089](https://github.com/matrix-org/matrix-doc/pull/3089) branch - a reference
@@ -164,14 +165,14 @@ export class MSC3089Branch {
      * @param {File | String | Buffer | ReadStream | Blob} encryptedContents The encrypted contents.
      * @param {Partial<IEncryptedFile>} info The encrypted file information.
      * @param {IContent} additionalContent Optional event content fields to include in the message.
-     * @returns {Promise<void>} Resolves when uploaded.
+     * @returns {Promise<ISendEventResponse>} Resolves to the file event's sent response.
      */
     public async createNewVersion(
         name: string,
         encryptedContents: FileType,
         info: Partial<IEncryptedFile>,
         additionalContent?: IContent,
-    ): Promise<void> {
+    ): Promise<ISendEventResponse> {
         const fileEventResponse = await this.directory.createFile(name, encryptedContents, info, {
             ...(additionalContent ?? {}),
             "m.new_content": true,
@@ -193,6 +194,8 @@ export class MSC3089Branch {
             ...(this.indexEvent.getContent()),
             active: false,
         }, this.id);
+
+        return fileEventResponse;
     }
 
     /**

src/models/event-timeline-set.ts

@@ -28,7 +28,6 @@ import { Room } from "./room";
 import { Filter } from "../filter";
 import { EventType, RelationType } from "../@types/event";
 import { RoomState } from "./room-state";
-import { Thread } from "./thread";
 
 // var DEBUG = false;
 const DEBUG = true;
@@ -53,6 +52,11 @@ export enum DuplicateStrategy {
     Replace = "replace",
 }
 
+export interface IRoomTimelineData {
+    timeline: EventTimeline;
+    liveEvent?: boolean;
+}
+
 export class EventTimelineSet extends EventEmitter {
     private readonly timelineSupport: boolean;
     private unstableClientRelationAggregation: boolean;
@@ -154,17 +158,12 @@ export class EventTimelineSet extends EventEmitter {
      *
      * @throws If <code>opts.pendingEventOrdering</code> was not 'detached'
      */
-    public getPendingEvents(thread?: Thread): MatrixEvent[] {
+    public getPendingEvents(): MatrixEvent[] {
         if (!this.room || !this.displayPendingEvents) {
             return [];
         }
 
-        const pendingEvents = this.room.getPendingEvents(thread);
-        if (this.filter) {
-            return this.filter.filterRoomTimeline(pendingEvents);
-        } else {
-            return pendingEvents;
-        }
+        return this.room.getPendingEvents();
     }
     /**
      * Get the live timeline for this room.
@@ -594,7 +593,7 @@ export class EventTimelineSet extends EventEmitter {
         this.setRelationsTarget(event);
         this.aggregateRelations(event);
 
-        const data = {
+        const data: IRoomTimelineData = {
             timeline: timeline,
             liveEvent: !toStartOfTimeline && timeline == this.liveTimeline && !fromCache,
         };
@@ -751,7 +750,7 @@ export class EventTimelineSet extends EventEmitter {
      */
     public getRelationsForEvent(
         eventId: string,
-        relationType: RelationType,
+        relationType: RelationType | string,
         eventType: EventType | string,
     ): Relations | undefined {
         if (!this.unstableClientRelationAggregation) {
@@ -769,6 +768,17 @@ export class EventTimelineSet extends EventEmitter {
         return relationsWithRelType[eventType];
     }
 
+    public getAllRelationsEventForEvent(eventId: string): MatrixEvent[] {
+        const relationsForEvent = this.relations[eventId] || {};
+        const events = [];
+        for (const relationsRecord of Object.values(relationsForEvent)) {
+            for (const relations of Object.values(relationsRecord)) {
+                events.push(...relations.getRelations());
+            }
+        }
+        return events;
+    }
+
     /**
      * Set an event as the target event if any Relations exist for it already
      *

src/models/event.ts

@@ -1,5 +1,5 @@
 /*
-Copyright 2015 - 2021 The Matrix.org Foundation C.I.C.
+Copyright 2015 - 2022 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@ limitations under the License.
  */
 
 import { EventEmitter } from 'events';
+import { ExtensibleEvent, ExtensibleEvents, Optional } from "matrix-events-sdk";
 
 import { logger } from '../logger';
 import { VerificationRequest } from "../crypto/verification/request/VerificationRequest";
@@ -28,6 +29,7 @@ import {
     EventType,
     MsgType,
     RelationType,
+    EVENT_VISIBILITY_CHANGE_TYPE,
 } from "../@types/event";
 import { Crypto, IEventDecryptionResult } from "../crypto";
 import { deepSortedObjectEntries } from "../utils";
@@ -89,6 +91,13 @@ export interface IUnsigned {
     redacted_because?: IEvent;
     transaction_id?: string;
     invite_room_state?: StrippedState[];
+    "m.relations"?: Record<RelationType | string, any>; // No common pattern for aggregated relations
+}
+
+export interface IThreadBundledRelationship {
+    latest_event: IEvent;
+    count: number;
+    current_user_participated?: boolean;
 }
 
 export interface IEvent {
@@ -110,7 +119,7 @@ export interface IEvent {
     age?: number;
 }
 
-interface IAggregatedRelation {
+export interface IAggregatedRelation {
     origin_server_ts: number;
     event_id?: string;
     sender?: string;
@@ -122,9 +131,42 @@ interface IAggregatedRelation {
 export interface IEventRelation {
     rel_type: RelationType | string;
     event_id: string;
+    "m.in_reply_to"?: {
+        event_id: string;
+        "m.render_in"?: string[];
+    };
     key?: string;
 }
 
+export interface IVisibilityEventRelation extends IEventRelation {
+    visibility: "visible" | "hidden";
+    reason?: string;
+}
+
+/**
+ * When an event is a visibility change event, as per MSC3531,
+ * the visibility change implied by the event.
+ */
+export interface IVisibilityChange {
+    /**
+     * If `true`, the target event should be made visible.
+     * Otherwise, it should be hidden.
+     */
+    visible: boolean;
+
+    /**
+     * The event id affected.
+     */
+    eventId: string;
+
+    /**
+     * Optionally, a human-readable reason explaining why
+     * the event was hidden. Ignored if the event was made
+     * visible.
+     */
+    reason: string | null;
+}
+
 export interface IClearEvent {
     room_id?: string;
     type: string;
@@ -143,6 +185,30 @@ export interface IDecryptOptions {
     isRetry?: boolean;
 }
 
+/**
+ * Message hiding, as specified by https://github.com/matrix-org/matrix-doc/pull/3531.
+ */
+export type MessageVisibility = IMessageVisibilityHidden | IMessageVisibilityVisible;
+/**
+ * Variant of `MessageVisibility` for the case in which the message should be displayed.
+ */
+export interface IMessageVisibilityVisible {
+    readonly visible: true;
+}
+/**
+ * Variant of `MessageVisibility` for the case in which the message should be hidden.
+ */
+export interface IMessageVisibilityHidden {
+    readonly visible: false;
+    /**
+     * Optionally, a human-readable reason to show to the user indicating why the
+     * message has been hidden (e.g. "Message Pending Moderation").
+     */
+    readonly reason: string | null;
+}
+// A singleton implementing `IMessageVisibilityVisible`.
+const MESSAGE_VISIBLE: IMessageVisibilityVisible = Object.freeze({ visible: true });
+
 export class MatrixEvent extends EventEmitter {
     private pushActions: IActionsObject = null;
     private _replacingEvent: MatrixEvent = null;
@@ -150,6 +216,18 @@ export class MatrixEvent extends EventEmitter {
     private _isCancelled = false;
     private clearEvent?: IClearEvent;
 
+    /* Message hiding, as specified by https://github.com/matrix-org/matrix-doc/pull/3531.
+
+    Note: We're returning this object, so any value stored here MUST be frozen.
+    */
+    private visibility: MessageVisibility = MESSAGE_VISIBLE;
+
+    // Not all events will be extensible-event compatible, so cache a flag in
+    // addition to a falsy cached event value. We check the flag later on in
+    // a public getter to decide if the cache is valid.
+    private _hasCachedExtEv = false;
+    private _cachedExtEv: Optional<ExtensibleEvent> = undefined;
+
     /* curve25519 key which we believe belongs to the sender of the event. See
      * getSenderKey()
      */
@@ -191,6 +269,7 @@ export class MatrixEvent extends EventEmitter {
      * A reference to the thread this event belongs to
      */
     private thread: Thread = null;
+    private threadId: string;
 
     /* Set an approximate timestamp for the event relative the local clock.
      * This will inherently be approximate because it doesn't take into account
@@ -198,7 +277,7 @@ export class MatrixEvent extends EventEmitter {
      * it to us and the time we're now constructing this event, but that's better
      * than assuming the local clock is in sync with the origin HS's clock.
      */
-    private readonly localTimestamp: number;
+    public localTimestamp: number;
 
     // XXX: these should be read-only
     public sender: RoomMember = null;
@@ -263,10 +342,29 @@ export class MatrixEvent extends EventEmitter {
         });
 
         this.txnId = event.txn_id || null;
-        this.localTimestamp = Date.now() - this.getAge();
+        this.localTimestamp = Date.now() - (this.getAge() ?? 0);
         this.reEmitter = new ReEmitter(this);
     }
 
+    /**
+     * Unstable getter to try and get an extensible event. Note that this might
+     * return a falsy value if the event could not be parsed as an extensible
+     * event.
+     *
+     * @deprecated Use stable functions where possible.
+     */
+    public get unstableExtensibleEvent(): Optional<ExtensibleEvent> {
+        if (!this._hasCachedExtEv) {
+            this._cachedExtEv = ExtensibleEvents.parse(this.getEffectiveEvent());
+        }
+        return this._cachedExtEv;
+    }
+
+    private invalidateExtensibleEvent() {
+        // just reset the flag - that'll trick the getter into parsing a new event
+        this._hasCachedExtEv = false;
+    }
+
     /**
      * Gets the event as though it would appear unencrypted. If the event is already not
      * encrypted, it is simply returned as-is.
@@ -339,10 +437,10 @@ export class MatrixEvent extends EventEmitter {
     /**
      * Get the room_id for this event. This will return <code>undefined</code>
      * for <code>m.presence</code> events.
-     * @return {string} The room ID, e.g. <code>!cURbafjkfsMDVwdRDQ:matrix.org
+     * @return {string?} The room ID, e.g. <code>!cURbafjkfsMDVwdRDQ:matrix.org
      * </code>
      */
-    public getRoomId(): string {
+    public getRoomId(): string | undefined {
         return this.event.room_id;
     }
 
@@ -409,10 +507,12 @@ export class MatrixEvent extends EventEmitter {
      * @experimental
      * Get the event ID of the thread head
      */
-    public get threadRootId(): string {
+    public get threadRootId(): string | undefined {
         const relatesTo = this.getWireContent()?.["m.relates_to"];
         if (relatesTo?.rel_type === RelationType.Thread) {
             return relatesTo.event_id;
+        } else {
+            return this.getThread()?.id || this.threadId;
         }
     }
 
@@ -420,26 +520,30 @@ export class MatrixEvent extends EventEmitter {
      * @experimental
      */
     public get isThreadRelation(): boolean {
-        return !!this.threadRootId;
+        return !!this.threadRootId && this.threadId !== this.getId();
     }
 
     /**
      * @experimental
      */
     public get isThreadRoot(): boolean {
-        // TODO, change the inner working of this getter for it to use the
-        // bundled relationship return on the event, view MSC3440
-        const thread = this.getThread();
-        return thread?.id === this.getId();
-    }
+        const threadDetails = this
+            .getServerAggregatedRelation<IThreadBundledRelationship>(RelationType.Thread);
 
-    public get parentEventId(): string {
-        return this.replyEventId || this.relationEventId;
+        // Bundled relationships only returned when the sync response is limited
+        // hence us having to check both bundled relation and inspect the thread
+        // model
+        return !!threadDetails || (this.getThread()?.id === this.getId());
     }
 
     public get replyEventId(): string {
-        const relations = this.getWireContent()["m.relates_to"];
-        return relations?.["m.in_reply_to"]?.["event_id"];
+        // We're prefer ev.getContent() over ev.getWireContent() to make sure
+        // we grab the latest edit with potentially new relations. But we also
+        // can't just rely on ev.getContent() by itself because historically we
+        // still show the reply from the original message even though the edit
+        // event does not include the relation reply.
+        const mRelatesTo = this.getContent()['m.relates_to'] || this.getWireContent()['m.relates_to'];
+        return mRelatesTo?.['m.in_reply_to']?.event_id;
     }
 
     public get relationEventId(): string {
@@ -475,9 +579,10 @@ export class MatrixEvent extends EventEmitter {
      * Get the age of this event. This represents the age of the event when the
      * event arrived at the device, and not the age of the event when this
      * function was called.
-     * @return {Number} The age of this event in milliseconds.
+     * Can only be returned once the server has echo'ed back
+     * @return {Number|undefined} The age of this event in milliseconds.
      */
-    public getAge(): number {
+    public getAge(): number | undefined {
         return this.getUnsigned().age || this.event.age; // v2 / v1
     }
 
@@ -570,7 +675,12 @@ export class MatrixEvent extends EventEmitter {
     }
 
     public shouldAttemptDecryption() {
-        return this.isEncrypted() && !this.isBeingDecrypted() && !this.clearEvent;
+        if (this.isRedacted()) return false;
+        if (this.isBeingDecrypted()) return false;
+        if (this.clearEvent) return false;
+        if (!this.isEncrypted()) return false;
+
+        return true;
     }
 
     /**
@@ -801,6 +911,7 @@ export class MatrixEvent extends EventEmitter {
         this.forwardingCurve25519KeyChain =
             decryptionResult.forwardingCurve25519KeyChain || [];
         this.untrusted = decryptionResult.untrusted || false;
+        this.invalidateExtensibleEvent();
     }
 
     /**
@@ -904,6 +1015,10 @@ export class MatrixEvent extends EventEmitter {
         return this.event.unsigned || {};
     }
 
+    public setUnsigned(unsigned: IUnsigned): void {
+        this.event.unsigned = unsigned;
+    }
+
     public unmarkLocallyRedacted(): boolean {
         const value = this._localRedactionEvent;
         this._localRedactionEvent = null;
@@ -923,6 +1038,53 @@ export class MatrixEvent extends EventEmitter {
         this.event.unsigned.redacted_because = redactionEvent.event as IEvent;
     }
 
+    /**
+     * Change the visibility of an event, as per https://github.com/matrix-org/matrix-doc/pull/3531 .
+     *
+     * @fires module:models/event.MatrixEvent#"Event.visibilityChange" if `visibilityEvent`
+     *   caused a change in the actual visibility of this event, either by making it
+     *   visible (if it was hidden), by making it hidden (if it was visible) or by
+     *   changing the reason (if it was hidden).
+     * @param visibilityEvent event holding a hide/unhide payload, or nothing
+     *   if the event is being reset to its original visibility (presumably
+     *   by a visibility event being redacted).
+     */
+    public applyVisibilityEvent(visibilityChange?: IVisibilityChange): void {
+        const visible = visibilityChange ? visibilityChange.visible : true;
+        const reason = visibilityChange ? visibilityChange.reason : null;
+        let change = false;
+        if (this.visibility.visible !== visibilityChange.visible) {
+            change = true;
+        } else if (!this.visibility.visible && this.visibility["reason"] !== reason) {
+            change = true;
+        }
+        if (change) {
+            if (visible) {
+                this.visibility = MESSAGE_VISIBLE;
+            } else {
+                this.visibility = Object.freeze({
+                    visible: false,
+                    reason: reason,
+                });
+            }
+            if (change) {
+                this.emit("Event.visibilityChange", this, visible);
+            }
+        }
+    }
+
+    /**
+     * Return instructions to display or hide the message.
+     *
+     * @returns Instructions determining whether the message
+     * should be displayed.
+     */
+    public messageVisibility(): MessageVisibility {
+        // Note: We may return `this.visibility` without fear, as
+        // this is a shallow frozen object.
+        return this.visibility;
+    }
+
     /**
      * Update the content of an event in the same way it would be by the server
      * if it were redacted before it was sent to us
@@ -972,6 +1134,8 @@ export class MatrixEvent extends EventEmitter {
                 delete content[key];
             }
         }
+
+        this.invalidateExtensibleEvent();
     }
 
     /**
@@ -992,6 +1156,54 @@ export class MatrixEvent extends EventEmitter {
         return this.getType() === EventType.RoomRedaction;
     }
 
+    /**
+     * Return the visibility change caused by this event,
+     * as per https://github.com/matrix-org/matrix-doc/pull/3531.
+     *
+     * @returns If the event is a well-formed visibility change event,
+     * an instance of `IVisibilityChange`, otherwise `null`.
+     */
+    public asVisibilityChange(): IVisibilityChange | null {
+        if (!EVENT_VISIBILITY_CHANGE_TYPE.matches(this.getType())) {
+            // Not a visibility change event.
+            return null;
+        }
+        const relation = this.getRelation();
+        if (!relation || relation.rel_type != "m.reference") {
+            // Ill-formed, ignore this event.
+            return null;
+        }
+        const eventId = relation.event_id;
+        if (!eventId) {
+            // Ill-formed, ignore this event.
+            return null;
+        }
+        const content = this.getWireContent();
+        const visible = !!content.visible;
+        const reason = content.reason;
+        if (reason && typeof reason != "string") {
+            // Ill-formed, ignore this event.
+            return null;
+        }
+        // Well-formed visibility change event.
+        return {
+            visible,
+            reason,
+            eventId,
+        };
+    }
+
+    /**
+     * Check if this event alters the visibility of another event,
+     * as per https://github.com/matrix-org/matrix-doc/pull/3531.
+     *
+     * @returns {boolean} True if this event alters the visibility
+     * of another event.
+     */
+    public isVisibilityEvent(): boolean {
+        return EVENT_VISIBILITY_CHANGE_TYPE.matches(this.getType());
+    }
+
     /**
      * Get the (decrypted, if necessary) redaction event JSON
      * if event was redacted
@@ -1053,6 +1265,8 @@ export class MatrixEvent extends EventEmitter {
             // emit the event if it changed
             this.emit("Event.localEventIdReplaced", this);
         }
+
+        this.localTimestamp = Date.now() - this.getAge();
     }
 
     /**
@@ -1127,6 +1341,7 @@ export class MatrixEvent extends EventEmitter {
         if (this._replacingEvent !== newEvent) {
             this._replacingEvent = newEvent;
             this.emit("Event.replaced", this);
+            this.invalidateExtensibleEvent();
         }
     }
 
@@ -1146,11 +1361,8 @@ export class MatrixEvent extends EventEmitter {
         return this.status;
     }
 
-    public getServerAggregatedRelation(relType: RelationType): IAggregatedRelation {
-        const relations = this.getUnsigned()["m.relations"];
-        if (relations) {
-            return relations[relType];
-        }
+    public getServerAggregatedRelation<T>(relType: RelationType): T | undefined {
+        return this.getUnsigned()["m.relations"]?.[relType];
     }
 
     /**
@@ -1159,7 +1371,7 @@ export class MatrixEvent extends EventEmitter {
      * @return {string?}
      */
     public replacingEventId(): string | undefined {
-        const replaceRelation = this.getServerAggregatedRelation(RelationType.Replace);
+        const replaceRelation = this.getServerAggregatedRelation<IAggregatedRelation>(RelationType.Replace);
         if (replaceRelation) {
             return replaceRelation.event_id;
         } else if (this._replacingEvent) {
@@ -1184,7 +1396,7 @@ export class MatrixEvent extends EventEmitter {
      * @return {Date?}
      */
     public replacingEventDate(): Date | undefined {
-        const replaceRelation = this.getServerAggregatedRelation(RelationType.Replace);
+        const replaceRelation = this.getServerAggregatedRelation<IAggregatedRelation>(RelationType.Replace);
         if (replaceRelation) {
             const ts = replaceRelation.origin_server_ts;
             if (Number.isFinite(ts)) {
@@ -1210,7 +1422,9 @@ export class MatrixEvent extends EventEmitter {
      */
     public getAssociatedId(): string | undefined {
         const relation = this.getRelation();
-        if (relation) {
+        if (this.replyEventId) {
+            return this.replyEventId;
+        } else if (relation) {
             return relation.event_id;
         } else if (this.isRedaction()) {
             return this.event.redacts;
@@ -1344,15 +1558,20 @@ export class MatrixEvent extends EventEmitter {
      */
     public setThread(thread: Thread): void {
         this.thread = thread;
+        this.setThreadId(thread.id);
         this.reEmitter.reEmit(thread, [ThreadEvent.Ready, ThreadEvent.Update]);
     }
 
     /**
      * @experimental
      */
-    public getThread(): Thread {
+    public getThread(): Thread | undefined {
         return this.thread;
     }
+
+    public setThreadId(threadId: string): void {
+        this.threadId = threadId;
+    }
 }
 
 /* REDACT_KEEP_KEYS gives the keys we keep when an event is redacted

src/models/related-relations.ts

@@ -0,0 +1,38 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { Relations } from "./relations";
+import { MatrixEvent } from "./event";
+
+export class RelatedRelations {
+    private relations: Relations[];
+
+    public constructor(relations: Relations[]) {
+        this.relations = relations.filter(r => !!r);
+    }
+
+    public getRelations(): MatrixEvent[] {
+        return this.relations.reduce((c, p) => [...c, ...p.getRelations()], []);
+    }
+
+    public on(ev: string, fn: (...params) => void) {
+        this.relations.forEach(r => r.on(ev, fn));
+    }
+
+    public off(ev: string, fn: (...params) => void) {
+        this.relations.forEach(r => r.off(ev, fn));
+    }
+}

src/models/relations.ts

@@ -16,7 +16,7 @@ limitations under the License.
 
 import { EventEmitter } from 'events';
 
-import { EventStatus, MatrixEvent } from './event';
+import { EventStatus, MatrixEvent, IAggregatedRelation } from './event';
 import { Room } from './room';
 import { logger } from '../logger';
 import { RelationType } from "../@types/event";
@@ -171,11 +171,11 @@ export class Relations extends EventEmitter {
      * @return {Array}
      * Relation events in insertion order.
      */
-    public getRelations() {
+    public getRelations(): MatrixEvent[] {
         return [...this.relations];
     }
 
-    private addAnnotationToAggregation(event: MatrixEvent) {
+    private addAnnotationToAggregation(event: MatrixEvent): void {
         const { key } = event.getRelation();
         if (!key) {
             return;
@@ -204,7 +204,7 @@ export class Relations extends EventEmitter {
         eventsFromSender.add(event);
     }
 
-    private removeAnnotationFromAggregation(event: MatrixEvent) {
+    private removeAnnotationFromAggregation(event: MatrixEvent): void {
         const { key } = event.getRelation();
         if (!key) {
             return;
@@ -240,7 +240,7 @@ export class Relations extends EventEmitter {
      * @param {MatrixEvent} redactedEvent
      * The original relation event that is about to be redacted.
      */
-    private onBeforeRedaction = async (redactedEvent: MatrixEvent) => {
+    private onBeforeRedaction = async (redactedEvent: MatrixEvent): Promise<void> => {
         if (!this.relations.has(redactedEvent)) {
             return;
         }
@@ -319,7 +319,7 @@ export class Relations extends EventEmitter {
 
         // the all-knowning server tells us that the event at some point had
         // this timestamp for its replacement, so any following replacement should definitely not be less
-        const replaceRelation = this.targetEvent.getServerAggregatedRelation(RelationType.Replace);
+        const replaceRelation = this.targetEvent.getServerAggregatedRelation<IAggregatedRelation>(RelationType.Replace);
         const minTs = replaceRelation && replaceRelation.origin_server_ts;
 
         const lastReplacement = this.getRelations().reduce((last, event) => {

src/models/room-member.ts

@@ -25,6 +25,7 @@ import * as utils from "../utils";
 import { User } from "./user";
 import { MatrixEvent } from "./event";
 import { RoomState } from "./room-state";
+import { logger } from "../logger";
 
 export class RoomMember extends EventEmitter {
     private _isOutOfBand = false;
@@ -116,6 +117,15 @@ export class RoomMember extends EventEmitter {
 
         const oldMembership = this.membership;
         this.membership = event.getDirectionalContent().membership;
+        if (this.membership === undefined) {
+            // logging to diagnose https://github.com/vector-im/element-web/issues/20962
+            // (logs event content, although only of membership events)
+            logger.trace(
+                `membership event with membership undefined (forwardLooking: ${event.forwardLooking})!`,
+                event.getContent(),
+                `prevcontent is `, event.getPrevContent(),
+            );
+        }
 
         this.disambiguate = shouldDisambiguate(
             this.userId,

src/models/room-state.ts

@@ -618,14 +618,14 @@ export class RoomState extends EventEmitter {
     }
 
     /**
-     * Returns true if the given MatrixClient has permission to send a state
-     * event of type `stateEventType` into this room.
-     * @param {string} stateEventType The type of state events to test
-     * @param {MatrixClient} cli The client to test permission for
-     * @return {boolean} true if the given client should be permitted to send
-     *                        the given type of state event into this room,
-     *                        according to the room's state.
-     */
+      * Returns true if the given MatrixClient has permission to send a state
+      * event of type `stateEventType` into this room.
+      * @param {string} stateEventType The type of state events to test
+      * @param {MatrixClient} cli The client to test permission for
+      * @return {boolean} true if the given client should be permitted to send
+      *                        the given type of state event into this room,
+      *                        according to the room's state.
+      */
     public mayClientSendStateEvent(stateEventType: EventType | string, cli: MatrixClient): boolean {
         if (cli.isGuest()) {
             return false;

src/models/room.ts

@@ -30,7 +30,10 @@ import { RoomMember } from "./room-member";
 import { IRoomSummary, RoomSummary } from "./room-summary";
 import { logger } from '../logger';
 import { ReEmitter } from '../ReEmitter';
-import { EventType, RoomCreateTypeField, RoomType, UNSTABLE_ELEMENT_FUNCTIONAL_USERS } from "../@types/event";
+import {
+    EventType, RoomCreateTypeField, RoomType, UNSTABLE_ELEMENT_FUNCTIONAL_USERS,
+    EVENT_VISIBILITY_CHANGE_TYPE,
+} from "../@types/event";
 import { IRoomVersionsCapability, MatrixClient, PendingEventOrdering, RoomVersionStability } from "../client";
 import { GuestAccess, HistoryVisibility, JoinRule, ResizeMethod } from "../@types/partials";
 import { Filter } from "../filter";
@@ -93,7 +96,7 @@ interface ICachedReceipt {
     data: IReceipt;
 }
 
-type ReceiptCache = Record<string, ICachedReceipt[]>;
+type ReceiptCache = {[eventId: string]: ICachedReceipt[]};
 
 interface IReceiptContent {
     [eventId: string]: {
@@ -103,7 +106,30 @@ interface IReceiptContent {
     };
 }
 
-type Receipts = Record<string, Record<string, IWrappedReceipt>>;
+const ReceiptPairRealIndex = 0;
+const ReceiptPairSyntheticIndex = 1;
+// We will only hold a synthetic receipt if we do not have a real receipt or the synthetic is newer.
+type Receipts = {
+    [receiptType: string]: {
+        [userId: string]: [IWrappedReceipt, IWrappedReceipt]; // Pair<real receipt, synthetic receipt> (both nullable)
+    };
+};
+
+// When inserting a visibility event affecting event `eventId`, we
+// need to scan through existing visibility events for `eventId`.
+// In theory, this could take an unlimited amount of time if:
+//
+// - the visibility event was sent by a moderator; and
+// - `eventId` already has many visibility changes (usually, it should
+//   be 2 or less); and
+// - for some reason, the visibility changes are received out of order
+//   (usually, this shouldn't happen at all).
+//
+// For this reason, we limit the number of events to scan through,
+// expecting that a broken visibility change for a single event in
+// an extremely uncommon case (possibly a DoS) is a small
+// price to pay to keep matrix-js-sdk responsive.
+const MAX_NUMBER_OF_VISIBILITY_EVENTS_TO_SCAN_THROUGH = 30;
 
 export enum NotificationCountType {
     Highlight = "highlight",
@@ -125,9 +151,7 @@ export class Room extends EventEmitter {
     // which pass in an event ID and get back some receipts, so we also store
     // a pre-cached list for this purpose.
     private receipts: Receipts = {}; // { receipt_type: { user_id: IReceipt } }
-    private receiptCacheByEventId: ReceiptCache = {}; // { event_id: IReceipt2[] }
-    // only receipts that came from the server, not synthesized ones
-    private realReceipts: Receipts = {};
+    private receiptCacheByEventId: ReceiptCache = {}; // { event_id: ICachedReceipt[] }
     private notificationCounts: Partial<Record<NotificationCountType, number>> = {};
     private readonly timelineSets: EventTimelineSet[];
     // any filtered timeline sets we're maintaining for this room
@@ -192,6 +216,25 @@ export class Room extends EventEmitter {
      * @experimental
      */
     public threads = new Map<string, Thread>();
+    public lastThread: Thread;
+
+    /**
+     * A mapping of eventId to all visibility changes to apply
+     * to the event, by chronological order, as per
+     * https://github.com/matrix-org/matrix-doc/pull/3531
+     *
+     * # Invariants
+     *
+     * - within each list, all events are classed by
+     *   chronological order;
+     * - all events are events such that
+     *  `asVisibilityEvent()` returns a non-null `IVisibilityChange`;
+     * - within each list with key `eventId`, all events
+     *   are in relation to `eventId`.
+     *
+     * @experimental
+     */
+    private visibilityEvents = new Map<string, MatrixEvent[]>();
 
     /**
      * Construct a new Room.
@@ -253,7 +296,9 @@ export class Room extends EventEmitter {
         // all our per-room timeline sets. the first one is the unfiltered ones;
         // the subsequent ones are the filtered ones in no particular order.
         this.timelineSets = [new EventTimelineSet(this, opts)];
-        this.reEmitter.reEmit(this.getUnfilteredTimelineSet(), ["Room.timeline", "Room.timelineReset"]);
+        this.reEmitter.reEmit(this.getUnfilteredTimelineSet(), [
+            "Room.timeline", "Room.timelineReset",
+        ]);
 
         this.fixUpLegacyTimelineFields();
 
@@ -468,16 +513,14 @@ export class Room extends EventEmitter {
      *
      * @throws If <code>opts.pendingEventOrdering</code> was not 'detached'
      */
-    public getPendingEvents(thread?: Thread): MatrixEvent[] {
+    public getPendingEvents(): MatrixEvent[] {
         if (this.opts.pendingEventOrdering !== PendingEventOrdering.Detached) {
             throw new Error(
                 "Cannot call getPendingEvents with pendingEventOrdering == " +
                 this.opts.pendingEventOrdering);
         }
 
-        return this.pendingEventList.filter(event => {
-            return !thread || thread.id === event.threadRootId;
-        });
+        return this.pendingEventList;
     }
 
     /**
@@ -1304,7 +1347,7 @@ export class Room extends EventEmitter {
         }
     }
 
-    public findThreadForEvent(event: MatrixEvent): Thread {
+    public findThreadForEvent(event: MatrixEvent): Thread | null {
         if (!event) {
             return null;
         }
@@ -1314,7 +1357,7 @@ export class Room extends EventEmitter {
         } else if (event.isThreadRoot) {
             return this.threads.get(event.getId());
         } else {
-            const parentEvent = this.findEventById(event.parentEventId);
+            const parentEvent = this.findEventById(event.getAssociatedId());
             return this.findThreadForEvent(parentEvent);
         }
     }
@@ -1332,37 +1375,61 @@ export class Room extends EventEmitter {
             let rootEvent = this.findEventById(event.threadRootId);
             // If the rootEvent does not exist in the current sync, then look for
             // it over the network
-            if (!rootEvent) {
-                const eventData = await this.client.fetchRoomEvent(this.roomId, event.threadRootId);
-                rootEvent = new MatrixEvent(eventData);
-            }
-            events.unshift(rootEvent);
-            thread = this.createThread(events);
-        }
+            try {
+                let eventData;
+                if (event.threadRootId) {
+                    eventData = await this.client.fetchRoomEvent(this.roomId, event.threadRootId);
+                }
 
-        if (event.getUnsigned().transaction_id) {
-            const existingEvent = this.txnToEvent[event.getUnsigned().transaction_id];
-            if (existingEvent) {
-                // remote echo of an event we sent earlier
-                this.handleRemoteEcho(event, existingEvent);
-                return;
+                if (!rootEvent) {
+                    rootEvent = new MatrixEvent(eventData);
+                } else {
+                    rootEvent.setUnsigned(eventData.unsigned);
+                }
+            } finally {
+                // The root event might be not be visible to the person requesting
+                // it. If it wasn't fetched successfully the thread will work
+                // in "limited" mode and won't benefit from all the APIs a homeserver
+                // can provide to enhance the thread experience
+                thread = this.createThread(rootEvent, events);
             }
         }
 
         this.emit(ThreadEvent.Update, thread);
     }
 
-    public createThread(events: MatrixEvent[]): Thread {
-        const thread = new Thread(events, this, this.client);
-        this.threads.set(thread.id, thread);
-        this.reEmitter.reEmit(thread, [
-            ThreadEvent.Update,
-            ThreadEvent.Ready,
-            "Room.timeline",
-            "Room.timelineReset",
-        ]);
-        this.emit(ThreadEvent.New, thread);
-        return thread;
+    public createThread(rootEvent: MatrixEvent | undefined, events: MatrixEvent[] = []): Thread | undefined {
+        if (rootEvent) {
+            const tl = this.getTimelineForEvent(rootEvent.getId());
+            const relatedEvents = tl?.getTimelineSet().getAllRelationsEventForEvent(rootEvent.getId());
+            if (relatedEvents) {
+                events = events.concat(relatedEvents);
+            }
+        }
+
+        const thread = new Thread(rootEvent, {
+            initialEvents: events,
+            room: this,
+            client: this.client,
+        });
+        // If we managed to create a thread and figure out its `id`
+        // then we can use it
+        if (thread.id) {
+            this.threads.set(thread.id, thread);
+            this.reEmitter.reEmit(thread, [
+                ThreadEvent.Update,
+                ThreadEvent.Ready,
+                "Room.timeline",
+                "Room.timelineReset",
+            ]);
+
+            if (!this.lastThread || this.lastThread.rootEvent.localTimestamp < rootEvent.localTimestamp) {
+                this.lastThread = thread;
+            }
+
+            this.emit(ThreadEvent.New, thread);
+            return thread;
+        }
     }
 
     /**
@@ -1402,6 +1469,15 @@ export class Room extends EventEmitter {
                 // (in the sender and target fields). We should get those
                 // RoomMember objects to update themselves when the events that
                 // they are based on are changed.
+
+                // Remove any visibility change on this event.
+                this.visibilityEvents.delete(redactId);
+
+                // If this event is a visibility change event, remove it from the
+                // list of visibility changes and update any event affected by it.
+                if (redactedEvent.isVisibilityEvent()) {
+                    this.redactVisibilityChangeEvent(event);
+                }
             }
 
             // FIXME: apply redactions to notification list
@@ -1411,6 +1487,15 @@ export class Room extends EventEmitter {
             // this may be needed to trigger an update.
         }
 
+        // Implement MSC3531: hiding messages.
+        if (event.isVisibilityEvent()) {
+            // This event changes the visibility of another event, record
+            // the visibility change, inform clients if necessary.
+            this.applyNewVisibilityEvent(event);
+        }
+        // If any pending visibility change is waiting for this (older) event,
+        this.applyPendingVisibilityEvents(event);
+
         if (event.getUnsigned().transaction_id) {
             const existingEvent = this.txnToEvent[event.getUnsigned().transaction_id];
             if (existingEvent) {
@@ -1477,8 +1562,7 @@ export class Room extends EventEmitter {
         EventTimeline.setEventMetadata(event, this.getLiveTimeline().getState(EventTimeline.FORWARDS), false);
 
         this.txnToEvent[txnId] = event;
-        const thread = this.threads.get(event.threadRootId);
-        if (this.opts.pendingEventOrdering === PendingEventOrdering.Detached && !thread) {
+        if (this.opts.pendingEventOrdering === PendingEventOrdering.Detached) {
             if (this.pendingEventList.some((e) => e.status === EventStatus.NOT_SENT)) {
                 logger.warn("Setting event as NOT_SENT due to messages in the same state");
                 event.setStatus(EventStatus.NOT_SENT);
@@ -1494,8 +1578,7 @@ export class Room extends EventEmitter {
 
             if (event.isRedaction()) {
                 const redactId = event.event.redacts;
-                let redactedEvent = this.pendingEventList &&
-                    this.pendingEventList.find(e => e.getId() === redactId);
+                let redactedEvent = this.pendingEventList?.find(e => e.getId() === redactId);
                 if (!redactedEvent) {
                     redactedEvent = this.findEventById(redactId);
                 }
@@ -1505,21 +1588,16 @@ export class Room extends EventEmitter {
                 }
             }
         } else {
-            if (thread) {
-                thread.timelineSet.addEventToTimeline(event,
-                    thread.timelineSet.getLiveTimeline(), false);
-            } else {
-                for (let i = 0; i < this.timelineSets.length; i++) {
-                    const timelineSet = this.timelineSets[i];
-                    if (timelineSet.getFilter()) {
-                        if (timelineSet.getFilter().filterRoomTimeline([event]).length) {
-                            timelineSet.addEventToTimeline(event,
-                                timelineSet.getLiveTimeline(), false);
-                        }
-                    } else {
+            for (let i = 0; i < this.timelineSets.length; i++) {
+                const timelineSet = this.timelineSets[i];
+                if (timelineSet.getFilter()) {
+                    if (timelineSet.getFilter().filterRoomTimeline([event]).length) {
                         timelineSet.addEventToTimeline(event,
                             timelineSet.getLiveTimeline(), false);
                     }
+                } else {
+                    timelineSet.addEventToTimeline(event,
+                        timelineSet.getLiveTimeline(), false);
                 }
             }
         }
@@ -1580,7 +1658,9 @@ export class Room extends EventEmitter {
         const thread = this.findThreadForEvent(event);
         if (thread) {
             thread.timelineSet.aggregateRelations(event);
-        } else {
+        }
+
+        if (thread?.id === event.getAssociatedId() || !thread) {
             // TODO: We should consider whether this means it would be a better
             // design to lift the relations handling up to the room instead.
             for (let i = 0; i < this.timelineSets.length; i++) {
@@ -1596,6 +1676,10 @@ export class Room extends EventEmitter {
         }
     }
 
+    public getEventForTxnId(txnId: string): MatrixEvent {
+        return this.txnToEvent[txnId];
+    }
+
     /**
      * Deal with the echo of a message we sent.
      *
@@ -1610,7 +1694,7 @@ export class Room extends EventEmitter {
      * @fires module:client~MatrixClient#event:"Room.localEchoUpdated"
      * @private
      */
-    private handleRemoteEcho(remoteEvent: MatrixEvent, localEvent: MatrixEvent): void {
+    public handleRemoteEcho(remoteEvent: MatrixEvent, localEvent: MatrixEvent): void {
         const oldEventId = localEvent.getId();
         const newEventId = remoteEvent.getId();
         const oldStatus = localEvent.status;
@@ -1632,10 +1716,12 @@ export class Room extends EventEmitter {
         // any, which is good, because we don't want to try decoding it again).
         localEvent.handleRemoteEcho(remoteEvent.event);
 
-        const thread = this.threads.get(remoteEvent.threadRootId);
+        const thread = this.findThreadForEvent(remoteEvent);
         if (thread) {
             thread.timelineSet.handleRemoteEcho(localEvent, oldEventId, newEventId);
-        } else {
+        }
+
+        if (thread?.id === remoteEvent.getAssociatedId() || !thread) {
             for (let i = 0; i < this.timelineSets.length; i++) {
                 const timelineSet = this.timelineSets[i];
 
@@ -1705,7 +1791,8 @@ export class Room extends EventEmitter {
             const thread = this.findThreadForEvent(event);
             if (thread) {
                 thread.timelineSet.replaceEventId(oldEventId, newEventId);
-            } else {
+            }
+            if (thread?.id === event.getAssociatedId() || !thread) {
                 // if the event was already in the timeline (which will be the case if
                 // opts.pendingEventOrdering==chronological), we need to update the
                 // timeline map.
@@ -1793,7 +1880,7 @@ export class Room extends EventEmitter {
             // TODO: We should have a filter to say "only add state event
             // types X Y Z to the timeline".
             this.addLiveEvent(events[i], duplicateStrategy, fromCache);
-            const thread = this.threads.get(events[i].getId());
+            const thread = this.findThreadForEvent(events[i]);
             if (thread) {
                 thread.addEvent(events[i], true);
             }
@@ -1899,19 +1986,12 @@ export class Room extends EventEmitter {
     }
 
     public getReadReceiptForUserId(userId: string, ignoreSynthesized = false): IWrappedReceipt | null {
-        let receipts = this.receipts;
+        const [realReceipt, syntheticReceipt] = this.receipts["m.read"]?.[userId] ?? [];
         if (ignoreSynthesized) {
-            receipts = this.realReceipts;
+            return realReceipt;
         }
 
-        if (
-            receipts["m.read"] === undefined ||
-            receipts["m.read"][userId] === undefined
-        ) {
-            return null;
-        }
-
-        return receipts["m.read"][userId];
+        return syntheticReceipt ?? realReceipt;
     }
 
     /**
@@ -1975,84 +2055,115 @@ export class Room extends EventEmitter {
     /**
      * Add a receipt event to the room.
      * @param {MatrixEvent} event The m.receipt event.
-     * @param {Boolean} fake True if this event is implicit
+     * @param {Boolean} synthetic True if this event is implicit.
      */
-    public addReceipt(event: MatrixEvent, fake = false): void {
-        if (!fake) {
-            this.addReceiptsToStructure(event, this.realReceipts);
-            // we don't bother caching real receipts by event ID
-            // as there's nothing that would read it.
-        }
-        this.addReceiptsToStructure(event, this.receipts);
-        this.receiptCacheByEventId = this.buildReceiptCache(this.receipts);
-
-        // send events after we've regenerated the cache, otherwise things that
-        // listened for the event would read from a stale cache
+    public addReceipt(event: MatrixEvent, synthetic = false): void {
+        this.addReceiptsToStructure(event, synthetic);
+        // send events after we've regenerated the structure & cache, otherwise things that
+        // listened for the event would read stale data.
         this.emit("Room.receipt", event, this);
     }
 
     /**
      * Add a receipt event to the room.
      * @param {MatrixEvent} event The m.receipt event.
-     * @param {Object} receipts The object to add receipts to
+     * @param {Boolean} synthetic True if this event is implicit.
      */
-    private addReceiptsToStructure(event: MatrixEvent, receipts: Receipts): void {
+    private addReceiptsToStructure(event: MatrixEvent, synthetic: boolean): void {
         const content = event.getContent<IReceiptContent>();
         Object.keys(content).forEach((eventId) => {
             Object.keys(content[eventId]).forEach((receiptType) => {
                 Object.keys(content[eventId][receiptType]).forEach((userId) => {
                     const receipt = content[eventId][receiptType][userId];
 
-                    if (!receipts[receiptType]) {
-                        receipts[receiptType] = {};
+                    if (!this.receipts[receiptType]) {
+                        this.receipts[receiptType] = {};
+                    }
+                    if (!this.receipts[receiptType][userId]) {
+                        this.receipts[receiptType][userId] = [null, null];
                     }
 
-                    const existingReceipt = receipts[receiptType][userId];
+                    const pair = this.receipts[receiptType][userId];
 
-                    if (!existingReceipt) {
-                        receipts[receiptType][userId] = {} as IWrappedReceipt;
-                    } else {
-                        // we only want to add this receipt if we think it is later
-                        // than the one we already have. (This is managed
-                        // server-side, but because we synthesize RRs locally we
-                        // have to do it here too.)
+                    let existingReceipt = pair[ReceiptPairRealIndex];
+                    if (synthetic) {
+                        existingReceipt = pair[ReceiptPairSyntheticIndex] ?? pair[ReceiptPairRealIndex];
+                    }
+
+                    if (existingReceipt) {
+                        // we only want to add this receipt if we think it is later than the one we already have.
+                        // This is managed server-side, but because we synthesize RRs locally we have to do it here too.
                         const ordering = this.getUnfilteredTimelineSet().compareEventOrdering(
-                            existingReceipt.eventId, eventId);
+                            existingReceipt.eventId,
+                            eventId,
+                        );
                         if (ordering !== null && ordering >= 0) {
                             return;
                         }
                     }
 
-                    receipts[receiptType][userId] = {
-                        eventId: eventId,
+                    const wrappedReceipt: IWrappedReceipt = {
+                        eventId,
                         data: receipt,
                     };
-                });
-            });
-        });
-    }
 
-    /**
-     * Build and return a map of receipts by event ID
-     * @param {Object} receipts A map of receipts
-     * @return {Object} Map of receipts by event ID
-     */
-    private buildReceiptCache(receipts: Receipts): ReceiptCache {
-        const receiptCacheByEventId: ReceiptCache = {};
-        Object.keys(receipts).forEach(function(receiptType) {
-            Object.keys(receipts[receiptType]).forEach(function(userId) {
-                const receipt = receipts[receiptType][userId];
-                if (!receiptCacheByEventId[receipt.eventId]) {
-                    receiptCacheByEventId[receipt.eventId] = [];
-                }
-                receiptCacheByEventId[receipt.eventId].push({
-                    userId: userId,
-                    type: receiptType,
-                    data: receipt.data,
+                    const realReceipt = synthetic ? pair[ReceiptPairRealIndex] : wrappedReceipt;
+                    const syntheticReceipt = synthetic ? wrappedReceipt : pair[ReceiptPairSyntheticIndex];
+
+                    let ordering: number | null = null;
+                    if (realReceipt && syntheticReceipt) {
+                        ordering = this.getUnfilteredTimelineSet().compareEventOrdering(
+                            realReceipt.eventId,
+                            syntheticReceipt.eventId,
+                        );
+                    }
+
+                    const preferSynthetic = ordering === null || ordering < 0;
+
+                    // we don't bother caching just real receipts by event ID as there's nothing that would read it.
+                    // Take the current cached receipt before we overwrite the pair elements.
+                    const cachedReceipt = pair[ReceiptPairSyntheticIndex] ?? pair[ReceiptPairRealIndex];
+
+                    if (synthetic && preferSynthetic) {
+                        pair[ReceiptPairSyntheticIndex] = wrappedReceipt;
+                    } else if (!synthetic) {
+                        pair[ReceiptPairRealIndex] = wrappedReceipt;
+
+                        if (!preferSynthetic) {
+                            pair[ReceiptPairSyntheticIndex] = null;
+                        }
+                    }
+
+                    const newCachedReceipt = pair[ReceiptPairSyntheticIndex] ?? pair[ReceiptPairRealIndex];
+                    if (cachedReceipt === newCachedReceipt) return;
+
+                    // clean up any previous cache entry
+                    if (cachedReceipt && this.receiptCacheByEventId[cachedReceipt.eventId]) {
+                        const previousEventId = cachedReceipt.eventId;
+                        // Remove the receipt we're about to clobber out of existence from the cache
+                        this.receiptCacheByEventId[previousEventId] = (
+                            this.receiptCacheByEventId[previousEventId].filter(r => {
+                                return r.type !== receiptType || r.userId !== userId;
+                            })
+                        );
+
+                        if (this.receiptCacheByEventId[previousEventId].length < 1) {
+                            delete this.receiptCacheByEventId[previousEventId]; // clean up the cache keys
+                        }
+                    }
+
+                    // cache the new one
+                    if (!this.receiptCacheByEventId[eventId]) {
+                        this.receiptCacheByEventId[eventId] = [];
+                    }
+                    this.receiptCacheByEventId[eventId].push({
+                        userId: userId,
+                        type: receiptType,
+                        data: receipt,
+                    });
                 });
             });
         });
-        return receiptCacheByEventId;
     }
 
     /**
@@ -2118,8 +2229,9 @@ export class Room extends EventEmitter {
      *                   message events into the room.
      */
     public maySendMessage(): boolean {
-        return this.getMyMembership() === 'join' &&
-            this.currentState.maySendEvent(EventType.RoomMessage, this.myUserId);
+        return this.getMyMembership() === 'join' && (this.client.isRoomEncrypted(this.roomId)
+            ? this.currentState.maySendEvent(EventType.RoomMessageEncrypted, this.myUserId)
+            : this.currentState.maySendEvent(EventType.RoomMessage, this.myUserId));
     }
 
     /**
@@ -2292,6 +2404,161 @@ export class Room extends EventEmitter {
             return "Empty room";
         }
     }
+
+    /**
+     * When we receive a new visibility change event:
+     *
+     * - store this visibility change alongside the timeline, in case we
+     *   later need to apply it to an event that we haven't received yet;
+     * - if we have already received the event whose visibility has changed,
+     *   patch it to reflect the visibility change and inform listeners.
+     */
+    private applyNewVisibilityEvent(event: MatrixEvent): void {
+        const visibilityChange = event.asVisibilityChange();
+        if (!visibilityChange) {
+            // The event is ill-formed.
+            return;
+        }
+
+        // Ignore visibility change events that are not emitted by moderators.
+        const userId = event.getSender();
+        if (!userId) {
+            return;
+        }
+        const isPowerSufficient =
+            (
+                EVENT_VISIBILITY_CHANGE_TYPE.name
+                && this.currentState.maySendStateEvent(EVENT_VISIBILITY_CHANGE_TYPE.name, userId)
+            )
+            || (
+                EVENT_VISIBILITY_CHANGE_TYPE.altName
+                && this.currentState.maySendStateEvent(EVENT_VISIBILITY_CHANGE_TYPE.altName, userId)
+            );
+        if (!isPowerSufficient) {
+            // Powerlevel is insufficient.
+            return;
+        }
+
+        // Record this change in visibility.
+        // If the event is not in our timeline and we only receive it later,
+        // we may need to apply the visibility change at a later date.
+
+        const visibilityEventsOnOriginalEvent = this.visibilityEvents.get(visibilityChange.eventId);
+        if (visibilityEventsOnOriginalEvent) {
+            // It would be tempting to simply erase the latest visibility change
+            // but we need to record all of the changes in case the latest change
+            // is ever redacted.
+            //
+            // In practice, linear scans through `visibilityEvents` should be fast.
+            // However, to protect against a potential DoS attack, we limit the
+            // number of iterations in this loop.
+            let index = visibilityEventsOnOriginalEvent.length - 1;
+            const min = Math.max(0,
+                visibilityEventsOnOriginalEvent.length - MAX_NUMBER_OF_VISIBILITY_EVENTS_TO_SCAN_THROUGH);
+            for (; index >= min; --index) {
+                const target = visibilityEventsOnOriginalEvent[index];
+                if (target.getTs() < event.getTs()) {
+                    break;
+                }
+            }
+            if (index === -1) {
+                visibilityEventsOnOriginalEvent.unshift(event);
+            } else {
+                visibilityEventsOnOriginalEvent.splice(index + 1, 0, event);
+            }
+        } else {
+            this.visibilityEvents.set(visibilityChange.eventId, [event]);
+        }
+
+        // Finally, let's check if the event is already in our timeline.
+        // If so, we need to patch it and inform listeners.
+
+        const originalEvent = this.findEventById(visibilityChange.eventId);
+        if (!originalEvent) {
+            return;
+        }
+        originalEvent.applyVisibilityEvent(visibilityChange);
+    }
+
+    private redactVisibilityChangeEvent(event: MatrixEvent) {
+        // Sanity checks.
+        if (!event.isVisibilityEvent) {
+            throw new Error("expected a visibility change event");
+        }
+        const relation = event.getRelation();
+        const originalEventId = relation.event_id;
+        const visibilityEventsOnOriginalEvent = this.visibilityEvents.get(originalEventId);
+        if (!visibilityEventsOnOriginalEvent) {
+            // No visibility changes on the original event.
+            // In particular, this change event was not recorded,
+            // most likely because it was ill-formed.
+            return;
+        }
+        const index = visibilityEventsOnOriginalEvent.findIndex(change => change.getId() === event.getId());
+        if (index === -1) {
+            // This change event was not recorded, most likely because
+            // it was ill-formed.
+            return;
+        }
+        // Remove visibility change.
+        visibilityEventsOnOriginalEvent.splice(index, 1);
+
+        // If we removed the latest visibility change event, propagate changes.
+        if (index === visibilityEventsOnOriginalEvent.length) {
+            const originalEvent = this.findEventById(originalEventId);
+            if (!originalEvent) {
+                return;
+            }
+            if (index === 0) {
+                // We have just removed the only visibility change event.
+                this.visibilityEvents.delete(originalEventId);
+                originalEvent.applyVisibilityEvent();
+            } else {
+                const newEvent = visibilityEventsOnOriginalEvent[visibilityEventsOnOriginalEvent.length - 1];
+                const newVisibility = newEvent.asVisibilityChange();
+                if (!newVisibility) {
+                    // Event is ill-formed.
+                    // This breaks our invariant.
+                    throw new Error("at this stage, visibility changes should be well-formed");
+                }
+                originalEvent.applyVisibilityEvent(newVisibility);
+            }
+        }
+    }
+
+    /**
+     * When we receive an event whose visibility has been altered by
+     * a (more recent) visibility change event, patch the event in
+     * place so that clients now not to display it.
+     *
+     * @param event Any matrix event. If this event has at least one a
+     * pending visibility change event, apply the latest visibility
+     * change event.
+     */
+    private applyPendingVisibilityEvents(event: MatrixEvent): void {
+        const visibilityEvents = this.visibilityEvents.get(event.getId());
+        if (!visibilityEvents || visibilityEvents.length == 0) {
+            // No pending visibility change in store.
+            return;
+        }
+        const visibilityEvent = visibilityEvents[visibilityEvents.length - 1];
+        const visibilityChange = visibilityEvent.asVisibilityChange();
+        if (!visibilityChange) {
+            return;
+        }
+        if (visibilityChange.visible) {
+            // Events are visible by default, no need to apply a visibility change.
+            // Note that we need to keep the visibility changes in `visibilityEvents`,
+            // in case we later fetch an older visibility change event that is superseded
+            // by `visibilityChange`.
+        }
+        if (visibilityEvent.getTs() < event.getTs()) {
+            // Something is wrong, the visibility change cannot happen before the
+            // event. Presumably an ill-formed event.
+            return;
+        }
+        event.applyVisibilityEvent(visibilityChange);
+    }
 }
 
 /**
@@ -2302,12 +2569,12 @@ function pendingEventsKey(roomId: string): string {
     return `mx_pending_events_${roomId}`;
 }
 
-/* a map from current event status to a list of allowed next statuses
-     */
+// a map from current event status to a list of allowed next statuses
 const ALLOWED_TRANSITIONS: Record<EventStatus, EventStatus[]> = {
     [EventStatus.ENCRYPTING]: [
         EventStatus.SENDING,
         EventStatus.NOT_SENT,
+        EventStatus.CANCELLED,
     ],
     [EventStatus.SENDING]: [
         EventStatus.ENCRYPTING,
@@ -2460,3 +2727,4 @@ function memberNamesToRoomName(names: string[], count = (names.length + 1)) {
  * @param {string} membership The new membership value
  * @param {string} prevMembership The previous membership value
  */
+

src/models/thread.ts

@@ -16,11 +16,14 @@ limitations under the License.
 
 import { MatrixClient } from "../matrix";
 import { ReEmitter } from "../ReEmitter";
-import { MatrixEvent } from "./event";
-import { EventTimeline } from "./event-timeline";
+import { RelationType } from "../@types/event";
+import { IRelationsRequestOpts } from "../@types/requests";
+import { MatrixEvent, IThreadBundledRelationship } from "./event";
+import { Direction, EventTimeline } from "./event-timeline";
 import { EventTimelineSet } from './event-timeline-set';
 import { Room } from './room';
 import { TypedEventEmitter } from "./typed-event-emitter";
+import { RoomState } from "./room-state";
 
 export enum ThreadEvent {
     New = "Thread.new",
@@ -30,14 +33,16 @@ export enum ThreadEvent {
     ViewThread = "Thred.viewThread",
 }
 
+interface IThreadOpts {
+    initialEvents?: MatrixEvent[];
+    room: Room;
+    client: MatrixClient;
+}
+
 /**
  * @experimental
  */
 export class Thread extends TypedEventEmitter<ThreadEvent> {
-    /**
-     * A reference to the event ID at the top of the thread
-     */
-    private root: string;
     /**
      * A reference to all the events ID at the bottom of the threads
      */
@@ -47,33 +52,55 @@ export class Thread extends TypedEventEmitter<ThreadEvent> {
 
     private reEmitter: ReEmitter;
 
+    private lastEvent: MatrixEvent;
+    private replyCount = 0;
+
+    public readonly room: Room;
+    public readonly client: MatrixClient;
+
+    public initialEventsFetched = false;
+
+    public readonly id: string;
+
     constructor(
-        events: MatrixEvent[] = [],
-        public readonly room: Room,
-        public readonly client: MatrixClient,
+        public readonly rootEvent: MatrixEvent | undefined,
+        opts: IThreadOpts,
     ) {
         super();
-        if (events.length === 0) {
-            throw new Error("Can't create an empty thread");
-        }
-
-        this.reEmitter = new ReEmitter(this);
 
+        this.room = opts.room;
+        this.client = opts.client;
         this.timelineSet = new EventTimelineSet(this.room, {
             unstableClientRelationAggregation: true,
             timelineSupport: true,
             pendingEvents: true,
         });
+        this.reEmitter = new ReEmitter(this);
 
         this.reEmitter.reEmit(this.timelineSet, [
             "Room.timeline",
             "Room.timelineReset",
         ]);
 
-        events.forEach(event => this.addEvent(event));
+        // If we weren't able to find the root event, it's probably missing
+        // and we define the thread ID from one of the thread relation
+        if (!rootEvent) {
+            this.id = opts?.initialEvents
+                ?.find(event => event.isThreadRelation)?.relationEventId;
+        } else {
+            this.id = rootEvent.getId();
+        }
+        this.initialiseThread(this.rootEvent);
 
-        room.on("Room.localEchoUpdated", this.onEcho);
-        room.on("Room.timeline", this.onEcho);
+        opts?.initialEvents?.forEach(event => this.addEvent(event));
+
+        this.room.on("Room.localEchoUpdated", this.onEcho);
+        this.room.on("Room.timeline", this.onEcho);
+    }
+
+    public get hasServerSideSupport(): boolean {
+        return this.client.cachedCapabilities
+            ?.capabilities?.[RelationType.Thread]?.enabled;
     }
 
     onEcho = (event: MatrixEvent) => {
@@ -82,6 +109,31 @@ export class Thread extends TypedEventEmitter<ThreadEvent> {
         }
     };
 
+    public get roomState(): RoomState {
+        return this.room.getLiveTimeline().getState(EventTimeline.FORWARDS);
+    }
+
+    private addEventToTimeline(event: MatrixEvent, toStartOfTimeline: boolean): void {
+        if (event.getUnsigned().transaction_id) {
+            const existingEvent = this.room.getEventForTxnId(event.getUnsigned().transaction_id);
+            if (existingEvent) {
+                // remote echo of an event we sent earlier
+                this.room.handleRemoteEcho(event, existingEvent);
+                return;
+            }
+        }
+
+        if (!this.findEventById(event.getId())) {
+            this.timelineSet.addEventToTimeline(
+                event,
+                this.liveTimeline,
+                toStartOfTimeline,
+                false,
+                this.roomState,
+            );
+        }
+    }
+
     /**
      * Add an event to the thread and updates
      * the tail/root references if needed
@@ -89,43 +141,88 @@ export class Thread extends TypedEventEmitter<ThreadEvent> {
      * @param event The event to add
      */
     public async addEvent(event: MatrixEvent, toStartOfTimeline = false): Promise<void> {
-        if (this.timelineSet.findEventById(event.getId()) || event.status !== null) {
-            return;
+        // Add all incoming events to the thread's timeline set when there's
+        // no server support
+        if (!this.hasServerSideSupport) {
+            // all the relevant membership info to hydrate events with a sender
+            // is held in the main room timeline
+            // We want to fetch the room state from there and pass it down to this thread
+            // timeline set to let it reconcile an event with its relevant RoomMember
+
+            event.setThread(this);
+            this.addEventToTimeline(event, toStartOfTimeline);
+
+            await this.client.decryptEventIfNeeded(event, {});
         }
 
-        if (!this.root) {
-            if (event.isThreadRelation) {
-                this.root = event.threadRootId;
-            } else {
-                this.root = event.getId();
+        if (this.hasServerSideSupport && this.initialEventsFetched) {
+            if (event.localTimestamp > this.lastReply().localTimestamp) {
+                this.addEventToTimeline(event, false);
             }
         }
 
-        // all the relevant membership info to hydrate events with a sender
-        // is held in the main room timeline
-        // We want to fetch the room state from there and pass it down to this thread
-        // timeline set to let it reconcile an event with its relevant RoomMember
-        const roomState = this.room.getLiveTimeline().getState(EventTimeline.FORWARDS);
-
-        event.setThread(this);
-        this.timelineSet.addEventToTimeline(
-            event,
-            this.timelineSet.getLiveTimeline(),
-            toStartOfTimeline,
-            false,
-            roomState,
-        );
-
         if (!this._currentUserParticipated && event.getSender() === this.client.getUserId()) {
             this._currentUserParticipated = true;
         }
 
-        await this.client.decryptEventIfNeeded(event, {});
-        this.emit(ThreadEvent.Update, this);
-
-        if (event.isThreadRelation) {
-            this.emit(ThreadEvent.NewReply, this, event);
+        const isThreadReply = event.getRelation()?.rel_type === RelationType.Thread;
+        // If no thread support exists we want to count all thread relation
+        // added as a reply. We can't rely on the bundled relationships count
+        if (!this.hasServerSideSupport && isThreadReply) {
+            this.replyCount++;
         }
+
+        // There is a risk that the `localTimestamp` approximation will not be accurate
+        // when threads are used over federation. That could results in the reply
+        // count value drifting away from the value returned by the server
+        if (!this.lastEvent || (isThreadReply && event.localTimestamp > this.replyToEvent.localTimestamp)) {
+            this.lastEvent = event;
+            if (this.lastEvent.getId() !== this.id) {
+                // This counting only works when server side support is enabled
+                // as we started the counting from the value returned in the
+                // bundled relationship
+                if (this.hasServerSideSupport) {
+                    this.replyCount++;
+                }
+
+                this.emit(ThreadEvent.NewReply, this, event);
+            }
+        }
+
+        this.emit(ThreadEvent.Update, this);
+    }
+
+    private initialiseThread(rootEvent: MatrixEvent | undefined): void {
+        const bundledRelationship = rootEvent
+            ?.getServerAggregatedRelation<IThreadBundledRelationship>(RelationType.Thread);
+
+        if (this.hasServerSideSupport && bundledRelationship) {
+            this.replyCount = bundledRelationship.count;
+            this._currentUserParticipated = bundledRelationship.current_user_participated;
+
+            const event = new MatrixEvent(bundledRelationship.latest_event);
+            this.setEventMetadata(event);
+            this.lastEvent = event;
+        }
+
+        if (!bundledRelationship && rootEvent) {
+            this.addEvent(rootEvent);
+        }
+    }
+
+    public async fetchInitialEvents(): Promise<boolean> {
+        try {
+            await this.fetchEvents();
+            this.initialEventsFetched = true;
+            return true;
+        } catch (e) {
+            return false;
+        }
+    }
+
+    private setEventMetadata(event: MatrixEvent): void {
+        EventTimeline.setEventMetadata(event, this.roomState, false);
+        event.setThread(this);
     }
 
     /**
@@ -138,28 +235,17 @@ export class Thread extends TypedEventEmitter<ThreadEvent> {
     /**
      * Return last reply to the thread
      */
-    public get lastReply(): MatrixEvent {
-        const threadReplies = this.events
-            .filter(event => event.isThreadRelation);
-        return threadReplies[threadReplies.length - 1];
-    }
-
-    /**
-     * The thread ID, which is the same as the root event ID
-     */
-    public get id(): string {
-        return this.root;
-    }
-
-    /**
-     * The thread root event
-     */
-    public get rootEvent(): MatrixEvent {
-        return this.findEventById(this.root);
+    public lastReply(matches: (ev: MatrixEvent) => boolean = () => true): MatrixEvent {
+        for (let i = this.events.length - 1; i >= 0; i--) {
+            const event = this.events[i];
+            if (matches(event)) {
+                return event;
+            }
+        }
     }
 
     public get roomId(): string {
-        return this.rootEvent.getRoomId();
+        return this.room.roomId;
     }
 
     /**
@@ -168,28 +254,18 @@ export class Thread extends TypedEventEmitter<ThreadEvent> {
      * exclude annotations from that number
      */
     public get length(): number {
-        return this.events
-            .filter(event => event.isThreadRelation)
-            .length;
+        return this.replyCount;
     }
 
     /**
      * A getter for the last event added to the thread
      */
     public get replyToEvent(): MatrixEvent {
-        const events = this.events;
-        return events[events.length -1];
+        return this.lastEvent;
     }
 
     public get events(): MatrixEvent[] {
-        return this.timelineSet.getLiveTimeline().getEvents();
-    }
-
-    public merge(thread: Thread): void {
-        thread.events.forEach(event => {
-            this.addEvent(event);
-        });
-        this.events.forEach(event => event.setThread(this));
+        return this.liveTimeline.getEvents();
     }
 
     public has(eventId: string): boolean {
@@ -199,4 +275,55 @@ export class Thread extends TypedEventEmitter<ThreadEvent> {
     public get hasCurrentUserParticipated(): boolean {
         return this._currentUserParticipated;
     }
+
+    public get liveTimeline(): EventTimeline {
+        return this.timelineSet.getLiveTimeline();
+    }
+
+    public async fetchEvents(opts: IRelationsRequestOpts = { limit: 20 }): Promise<{
+        originalEvent: MatrixEvent;
+        events: MatrixEvent[];
+        nextBatch?: string;
+        prevBatch?: string;
+    }> {
+        let {
+            originalEvent,
+            events,
+            prevBatch,
+            nextBatch,
+        } = await this.client.relations(
+            this.room.roomId,
+            this.id,
+            RelationType.Thread,
+            null,
+            opts,
+        );
+
+        // When there's no nextBatch returned with a `from` request we have reached
+        // the end of the thread, and therefore want to return an empty one
+        if (!opts.to && !nextBatch) {
+            events = [originalEvent, ...events];
+        }
+
+        for (const event of events) {
+            await this.client.decryptEventIfNeeded(event);
+            this.setEventMetadata(event);
+        }
+
+        const prependEvents = !opts.direction || opts.direction === Direction.Backward;
+
+        this.timelineSet.addEventsToTimeline(
+            events,
+            prependEvents,
+            this.liveTimeline,
+            prependEvents ? nextBatch : prevBatch,
+        );
+
+        return {
+            originalEvent,
+            events,
+            prevBatch,
+            nextBatch,
+        };
+    }
 }

src/sync-accumulator.ts

@@ -32,6 +32,7 @@ interface IOpts {
 export interface IMinimalEvent {
     content: IContent;
     type: EventType | string;
+    unsigned?: IUnsigned;
 }
 
 export interface IEphemeral {

src/sync.ts

@@ -201,6 +201,7 @@ export class SyncApi {
             "Room.accountData",
             "Room.myMembership",
             "Room.replaceEvent",
+            "Room.visibilityChange",
         ]);
         this.registerStateListeners(room);
         return room;
@@ -283,7 +284,7 @@ export class SyncApi {
                 leaveRooms = this.mapSyncResponseToRoomArray(data.rooms.leave);
             }
             const rooms = [];
-            leaveRooms.forEach((leaveObj) => {
+            leaveRooms.forEach(async (leaveObj) => {
                 const room = leaveObj.room;
                 rooms.push(room);
                 if (!leaveObj.isBrandNewRoom) {
@@ -309,7 +310,7 @@ export class SyncApi {
                     EventTimeline.BACKWARDS);
 
                 this.processRoomEvents(room, stateEvents, timelineEvents);
-                this.processThreadEvents(room, threadedEvents);
+                await this.processThreadEvents(room, threadedEvents);
 
                 room.recalculate();
                 client.store.storeRoom(room);
@@ -1306,7 +1307,7 @@ export class SyncApi {
             const [timelineEvents, threadedEvents] = this.client.partitionThreadedEvents(events);
 
             this.processRoomEvents(room, stateEvents, timelineEvents, syncEventData.fromCache);
-            this.processThreadEvents(room, threadedEvents);
+            await this.processThreadEvents(room, threadedEvents);
 
             // set summary after processing events,
             // because it will trigger a name calculation
@@ -1365,7 +1366,7 @@ export class SyncApi {
         });
 
         // Handle leaves (e.g. kicked rooms)
-        leaveRooms.forEach((leaveObj) => {
+        leaveRooms.forEach(async (leaveObj) => {
             const room = leaveObj.room;
             const stateEvents = this.mapSyncEventsFormat(leaveObj.state, room);
             const events = this.mapSyncEventsFormat(leaveObj.timeline, room);
@@ -1374,7 +1375,7 @@ export class SyncApi {
             const [timelineEvents, threadedEvents] = this.client.partitionThreadedEvents(events);
 
             this.processRoomEvents(room, stateEvents, timelineEvents);
-            this.processThreadEvents(room, threadedEvents);
+            await this.processThreadEvents(room, threadedEvents);
             room.addAccountData(accountDataEvents);
 
             room.recalculate();
@@ -1719,14 +1720,14 @@ export class SyncApi {
     /**
      * @experimental
      */
-    private processThreadEvents(room: Room, threadedEvents: MatrixEvent[]): void {
+    private processThreadEvents(room: Room, threadedEvents: MatrixEvent[]): Promise<void> {
         return this.client.processThreadEvents(room, threadedEvents);
     }
 
     // extractRelatedEvents(event: MatrixEvent, events: MatrixEvent[], relatedEvents: MatrixEvent[] = []): MatrixEvent[] {
     //     relatedEvents.push(event);
 
-    //     const parentEventId = event.parentEventId;
+    //     const parentEventId = event.getAssociatedId();
     //     const parentEventIndex = events.findIndex(event => event.getId() === parentEventId);
 
     //     if (parentEventIndex > -1) {

src/webrtc/call.ts

@@ -937,7 +937,7 @@ export class MatrixCall extends EventEmitter {
             const upgradeVideo = video && !this.hasLocalUserMediaVideoTrack;
             logger.debug(`Upgrading call: audio?=${upgradeAudio} video?=${upgradeVideo}`);
 
-            const stream = await this.client.getMediaHandler().getUserMediaStream(upgradeAudio, upgradeVideo);
+            const stream = await this.client.getMediaHandler().getUserMediaStream(upgradeAudio, upgradeVideo, false);
             if (upgradeAudio && upgradeVideo) {
                 if (this.hasLocalUserMediaAudioTrack) return;
                 if (this.hasLocalUserMediaVideoTrack) return;
@@ -1717,7 +1717,12 @@ export class MatrixCall extends EventEmitter {
 
         const stream = ev.streams[0];
         this.pushRemoteFeed(stream);
-        stream.addEventListener("removetrack", () => this.deleteFeedByStream(stream));
+        stream.addEventListener("removetrack", () => {
+            if (stream.getTracks().length === 0) {
+                logger.info(`Stream ID ${stream.id} has no tracks remaining - removing`);
+                this.deleteFeedByStream(stream);
+            }
+        });
     };
 
     private onDataChannel = (ev: RTCDataChannelEvent): void => {
@@ -1938,7 +1943,7 @@ export class MatrixCall extends EventEmitter {
 
         await this.sendVoipEvent(EventType.CallReplaces, bodyToTransferee);
 
-        await this.terminate(CallParty.Local, CallErrorCode.Replaced, true);
+        await this.terminate(CallParty.Local, CallErrorCode.Transfered, true);
         await transferTargetCall.terminate(CallParty.Local, CallErrorCode.Transfered, true);
     }
 
@@ -1973,7 +1978,7 @@ export class MatrixCall extends EventEmitter {
     }
 
     private stopAllMedia(): void {
-        logger.debug(`stopAllMedia (stream=${this.localUsermediaStream})`);
+        logger.debug("Stopping all media for call", this.callId);
 
         for (const feed of this.feeds) {
             if (feed.isLocal() && feed.purpose === SDPStreamMetadataPurpose.Usermedia) {
@@ -1981,6 +1986,7 @@ export class MatrixCall extends EventEmitter {
             } else if (feed.isLocal() && feed.purpose === SDPStreamMetadataPurpose.Screenshare) {
                 this.client.getMediaHandler().stopScreensharingStream(feed.stream);
             } else {
+                logger.debug("Stopping remote stream", feed.stream.id);
                 for (const track of feed.stream.getTracks()) {
                     track.stop();
                 }

src/webrtc/callEventHandler.ts

@@ -257,7 +257,11 @@ export class CallEventHandler {
                     } else {
                         call.onRejectReceived(content as MCallHangupReject);
                     }
-                    this.calls.delete(content.call_id);
+
+                    // @ts-expect-error typescript thinks the state can't be 'ended' because we're
+                    // inside the if block where it wasn't, but it could have changed because
+                    // on[Hangup|Reject]Received are side-effecty.
+                    if (call.state === CallState.Ended) this.calls.delete(content.call_id);
                 }
             }
             return;

src/webrtc/mediaHandler.ts

@@ -54,9 +54,12 @@ export class MediaHandler {
     }
 
     /**
+     * @param audio should have an audio track
+     * @param video should have a video track
+     * @param reusable is allowed to be reused by the MediaHandler
      * @returns {MediaStream} based on passed parameters
      */
-    public async getUserMediaStream(audio: boolean, video: boolean): Promise<MediaStream> {
+    public async getUserMediaStream(audio: boolean, video: boolean, reusable = true): Promise<MediaStream> {
         const shouldRequestAudio = audio && await this.hasAudioDevice();
         const shouldRequestVideo = video && await this.hasVideoDevice();
 
@@ -78,7 +81,9 @@ export class MediaHandler {
             stream = await navigator.mediaDevices.getUserMedia(constraints);
         }
 
-        this.userMediaStreams.push(stream);
+        if (reusable) {
+            this.userMediaStreams.push(stream);
+        }
 
         return stream;
     }
@@ -101,9 +106,11 @@ export class MediaHandler {
     }
 
     /**
+     * @param desktopCapturerSourceId sourceId for Electron DesktopCapturer
+     * @param reusable is allowed to be reused by the MediaHandler
      * @returns {MediaStream} based on passed parameters
      */
-    public async getScreensharingStream(desktopCapturerSourceId: string): Promise<MediaStream | null> {
+    public async getScreensharingStream(desktopCapturerSourceId: string, reusable = true): Promise<MediaStream | null> {
         let stream: MediaStream;
 
         if (this.screensharingStreams.length === 0) {
@@ -125,7 +132,9 @@ export class MediaHandler {
             stream = matchingStream.clone();
         }
 
-        this.screensharingStreams.push(stream);
+        if (reusable) {
+            this.screensharingStreams.push(stream);
+        }
 
         return stream;
     }