make errors more verbose

.github/PULL_REQUEST_TEMPLATE.md

@@ -5,7 +5,7 @@
 > Every PR must have a linked issue
 > that a maintainer has reviewed and approved **before you started writing code**.
 > PRs that don't meet this requirement will not be reviewed.
-> See [CONTRIBUTING.md](https://github.com/element-hq/element-call/blob/main/CONTRIBUTING.md) for ElementCall decided for this approach.
+> See [CONTRIBUTING.md](https://github.com/element-hq/element-call/blob/livekit/CONTRIBUTING.md) for ElementCall decided for this approach.
 
 ## Content
 
@@ -39,7 +39,7 @@ Uncomment the markdown table below and fill in the last line:
 ## Checklist
 
 - [ ] A linked, pre-approved issue exists for this feature or UI change.
-- [ ] I have read [CONTRIBUTING.md](https://github.com/element-hq/element-call/blob/main/CONTRIBUTING.md) in full.
+- [ ] I have read [CONTRIBUTING.md](https://github.com/element-hq/element-call/blob/livekit/CONTRIBUTING.md) in full.
 - [ ] Pull request includes screenshots or videos for any UI changes.
 - [ ] Tests written for new code (and existing touched code where feasible).
 - [ ] Linter and other CI checks pass.

.github/workflows/build.yaml

@@ -6,7 +6,7 @@ on:
       - opened
       - labeled
   push:
-    branches: [main]
+    branches: [livekit, full-mesh]
 jobs:
   build_full_element_call:
     # Use the full package vite build
@@ -22,8 +22,8 @@ jobs:
       SENTRY_AUTH_TOKEN: ${{ secrets.SENTRY_AUTH_TOKEN }}
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
   deploy_develop:
-    # Deploy main branch to call.element.dev after build completes
-    if: github.ref == 'refs/heads/main'
+    # Deploy livekit branch to call.element.dev after build completes
+    if: github.ref == 'refs/heads/livekit'
     needs: build_full_element_call
     runs-on: ubuntu-latest
     steps:
@@ -43,8 +43,8 @@ jobs:
                 }
             })
   docker_for_develop:
-    # Build docker and publish docker for main branch after build completes
-    if: github.ref == 'refs/heads/main'
+    # Build docker and publish docker for livekit branch after build completes
+    if: github.ref == 'refs/heads/livekit'
     needs: build_full_element_call
     permissions:
       contents: write

docker-compose-playwright.yml

@@ -13,7 +13,7 @@ services:
       - ./backend/playwright_homeserver-othersite.yaml:/data/cfg/homeserver.yaml:Z
   element-web:
     # Pin to a SHA so that upstream cannot break our tests. Renovate handles regular updates.
-    image: ghcr.io/element-hq/element-web:develop@sha256:6ed62b2963ae098a1f79521eb516834dcf29452168e281cc359d9cfb4380adf6
+    image: ghcr.io/element-hq/element-web:develop@sha256:133160c3c1e506276145cbb8ccaf48253f0a96af635129d785826265e4f3ca10
   element-web-1:
     # Pin to a SHA so that upstream cannot break our tests. Renovate handles regular updates.
-    image: ghcr.io/element-hq/element-web:develop@sha256:6ed62b2963ae098a1f79521eb516834dcf29452168e281cc359d9cfb4380adf6
+    image: ghcr.io/element-hq/element-web:develop@sha256:133160c3c1e506276145cbb8ccaf48253f0a96af635129d785826265e4f3ca10

locales/en/app.json

@@ -116,7 +116,6 @@
     "peer_connection_timeout_description": "Connection to the media server timed out. Try switching to a different network or disabling your VPN. If the problem persists, see our <0>troubleshooting guide</0> or contact your server administrator.",
     "room_creation_restricted": "Failed to create call",
     "room_creation_restricted_description": "Call creation might be restricted to authorized users only. Try again later, or contact your server admin if the problem persists.",
-    "screen_share_failed": "Could not start screen sharing",
     "sticky_events_required": "Homeserver does not support Matrix 2.0 calls",
     "sticky_events_required_description": "This deployment is configured to use Matrix 2.0 call mode, but the homeserver does not advertise support for sticky events (MSC4354). Ask your server admin to upgrade, or switch the deployment to a compatible mode.",
     "unexpected_ec_error": "An unexpected error occurred (<0>Error Code:</0> <1>{{ errorCode }}</1>). Please contact your server admin."

playwright/fixtures/widget-user.ts

@@ -153,7 +153,7 @@ export const widgetTest = test.extend<MyFixtures>({
 
       // Accept the DM invite from brooks
       // This how playwright record selects the DM invite in the room list
-      await ewPage2.getByRole("button", { name: "Open room" }).click();
+      await ewPage2.getByRole("option", { name: "Open room" }).click();
       await ewPage2.getByRole("button", { name: "Start chatting" }).click();
     }
 

pnpm-lock.yaml

@@ -39,13 +39,13 @@ importers:
         version: 11.7.12
       '@livekit/components-core':
         specifier: ^0.12.0
-        version: 0.12.15(livekit-client@2.22.2(@types/dom-mediacapture-record@1.0.22))(tslib@2.8.1)
+        version: 0.12.15(livekit-client@2.22.0(@types/dom-mediacapture-record@1.0.22))(tslib@2.8.1)
       '@livekit/components-react':
         specifier: ^2.0.0
-        version: 2.9.24(livekit-client@2.22.2(@types/dom-mediacapture-record@1.0.22))(react-dom@19.2.8(react@19.2.8))(react@19.2.8)(tslib@2.8.1)
+        version: 2.9.24(livekit-client@2.22.0(@types/dom-mediacapture-record@1.0.22))(react-dom@19.2.8(react@19.2.8))(react@19.2.8)(tslib@2.8.1)
       '@livekit/track-processors':
         specifier: ^0.7.1
-        version: 0.7.2(@types/dom-mediacapture-transform@0.1.11)(livekit-client@2.22.2(@types/dom-mediacapture-record@1.0.22))
+        version: 0.7.2(@types/dom-mediacapture-transform@0.1.11)(livekit-client@2.22.0(@types/dom-mediacapture-record@1.0.22))
       '@mediapipe/tasks-vision':
         specifier: ^0.10.18
         version: 0.10.35
@@ -183,7 +183,7 @@ importers:
         version: 5.88.1(@emnapi/core@1.11.2)(@emnapi/runtime@1.11.2)(@types/node@24.13.3)(typescript@5.9.3)
       livekit-client:
         specifier: ^2.18.1
-        version: 2.22.2(@types/dom-mediacapture-record@1.0.22)
+        version: 2.22.0(@types/dom-mediacapture-record@1.0.22)
       lodash-es:
         specifier: ^4.17.21
         version: 4.18.1
@@ -195,7 +195,7 @@ importers:
         version: https://codeload.github.com/matrix-org/matrix-js-sdk/tar.gz/24929be0e741be6a5d0a7226f1c682e245263b8a
       matrix-widget-api:
         specifier: ^1.18.0
-        version: 1.19.0
+        version: 1.18.0
       node-stdlib-browser:
         specifier: ^1.3.1
         version: 1.3.1
@@ -4465,8 +4465,8 @@ packages:
     resolution: {integrity: sha512-AC/7JofJvZGrrneWNaEnJeOLUx+JlGt7tNa0wZiRPT4MY1wmfKjt2+6O2p2uz2+skll8OZZmJMNqeke7kKbNgQ==}
     hasBin: true
 
-  jose@6.2.12:
-    resolution: {integrity: sha512-9NiFmJEex0sy2Dk58j2UGBSHgUs2ypF9eZSu4L6vjOX3Dp96Sw1F3uL+H+D1sx02jZZdzUT0HgvCy59CuvXcWw==}
+  jose@6.2.10:
+    resolution: {integrity: sha512-iiW7J9qRFlGxvCOIBDBDxFePQSn7ZMAnrYGhrrOo6siO/MIqwfyilLR27pkfDgUk+raLuzADS8A3S/KLBisc0g==}
 
   jose@6.2.9:
     resolution: {integrity: sha512-XrchZOFZUl/T3vTwRe8XK+cJrGtMF4th1ARnDfwbBXFKThGhlsxEE4Zu03AD/bjJSt/9jT/mxrOCkJWOg77aPA==}
@@ -4614,8 +4614,8 @@ packages:
   lines-and-columns@1.2.4:
     resolution: {integrity: sha512-7ylylesZQ/PV29jhEDl3Ufjo6ZX7gCqJr5F7PKrqc93v7fzSymt1BpwEU8nAUXs8qzzvqhbjhK5QZg6Mt/HkBg==}
 
-  livekit-client@2.22.2:
-    resolution: {integrity: sha512-o3yLYoH2eHVR/DmIZzgC96FMvtR4+g/DjeqNwS5zp12EjqrqiRULxm6Oq/YsTE97WnA6fhy23+a2hGkbce5SPA==}
+  livekit-client@2.22.0:
+    resolution: {integrity: sha512-GLtYQfRh/RsvXaOX1x609bFZ17yyKmKWDqu9JmkMKn9vIFLi2GsapRv9gT8OJO/1R2dsitrkbGmloyUfxWQsaA==}
     peerDependencies:
       '@types/dom-mediacapture-record': ^1
 
@@ -4664,10 +4664,6 @@ packages:
     resolution: {integrity: sha512-h5bgJWpxJNswbU7qCrV0tIKQCaS3blPDrqKWx+QxzuzL1zGUzij9XCWLrSLsJPu5t+eWA/ycetzYAO5IOMcWAQ==}
     hasBin: true
 
-  machina@7.0.1:
-    resolution: {integrity: sha512-0Xkgs8NeBvO2hW6bjJT8ewLWrMfh1haMPstaghpASWjXkLjRhtDiaJG1Kb7mslaOHxZYxpH7PIjpmirRVYbMMA==}
-    engines: {node: '>=22.22'}
-
   magic-string@0.30.21:
     resolution: {integrity: sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ==}
 
@@ -4694,8 +4690,8 @@ packages:
     version: 42.2.0
     engines: {node: '>=22.0.0'}
 
-  matrix-widget-api@1.19.0:
-    resolution: {integrity: sha512-Qe7L6G1mQJphBC47/Bzp5ljPIK1UARgLiuGgS+/KmEs/eaNHkQ3+ArD0/0kvMV+d6kCGAZ9OKRqsnuPjizI+tw==}
+  matrix-widget-api@1.18.0:
+    resolution: {integrity: sha512-4T2f2koWmx05p1BLcT/9YGGGPSXpPT+PA4Oap/5fjhXsWPxMGJiGL97YpANMYLKsnE1sScYFeuyxIgdc1Qo+Ew==}
 
   md5.js@1.3.5:
     resolution: {integrity: sha512-xitP+WxNPcTTOgnTJcrhM0xvdPepipPSf3I8EIpGKeFLjt3PlJLIDG3u8EX53ZIubkb+5U2+3rELYpEhHhzdkg==}
@@ -7074,21 +7070,21 @@ snapshots:
       '@jridgewell/resolve-uri': 3.1.2
       '@jridgewell/sourcemap-codec': 1.5.5
 
-  '@livekit/components-core@0.12.15(livekit-client@2.22.2(@types/dom-mediacapture-record@1.0.22))(tslib@2.8.1)':
+  '@livekit/components-core@0.12.15(livekit-client@2.22.0(@types/dom-mediacapture-record@1.0.22))(tslib@2.8.1)':
     dependencies:
       '@floating-ui/dom': 1.7.6
-      livekit-client: 2.22.2(@types/dom-mediacapture-record@1.0.22)
+      livekit-client: 2.22.0(@types/dom-mediacapture-record@1.0.22)
       loglevel: 1.9.1
       rxjs: 7.8.2
       tslib: 2.8.1
 
-  '@livekit/components-react@2.9.24(livekit-client@2.22.2(@types/dom-mediacapture-record@1.0.22))(react-dom@19.2.8(react@19.2.8))(react@19.2.8)(tslib@2.8.1)':
+  '@livekit/components-react@2.9.24(livekit-client@2.22.0(@types/dom-mediacapture-record@1.0.22))(react-dom@19.2.8(react@19.2.8))(react@19.2.8)(tslib@2.8.1)':
     dependencies:
-      '@livekit/components-core': 0.12.15(livekit-client@2.22.2(@types/dom-mediacapture-record@1.0.22))(tslib@2.8.1)
+      '@livekit/components-core': 0.12.15(livekit-client@2.22.0(@types/dom-mediacapture-record@1.0.22))(tslib@2.8.1)
       clsx: 2.1.1
       events: 3.3.0
       jose: 6.2.9
-      livekit-client: 2.22.2(@types/dom-mediacapture-record@1.0.22)
+      livekit-client: 2.22.0(@types/dom-mediacapture-record@1.0.22)
       react: 19.2.8
       react-dom: 19.2.8(react@19.2.8)
       tslib: 2.8.1
@@ -7100,11 +7096,11 @@ snapshots:
     dependencies:
       '@bufbuild/protobuf': 1.10.1
 
-  '@livekit/track-processors@0.7.2(@types/dom-mediacapture-transform@0.1.11)(livekit-client@2.22.2(@types/dom-mediacapture-record@1.0.22))':
+  '@livekit/track-processors@0.7.2(@types/dom-mediacapture-transform@0.1.11)(livekit-client@2.22.0(@types/dom-mediacapture-record@1.0.22))':
     dependencies:
       '@mediapipe/tasks-vision': 0.10.35
       '@types/dom-mediacapture-transform': 0.1.11
-      livekit-client: 2.22.2(@types/dom-mediacapture-record@1.0.22)
+      livekit-client: 2.22.0(@types/dom-mediacapture-record@1.0.22)
 
   '@matrix-org/matrix-sdk-crypto-wasm@18.5.0': {}
 
@@ -10063,7 +10059,7 @@ snapshots:
 
   jiti@2.7.0: {}
 
-  jose@6.2.12: {}
+  jose@6.2.10: {}
 
   jose@6.2.9: {}
 
@@ -10207,15 +10203,14 @@ snapshots:
 
   lines-and-columns@1.2.4: {}
 
-  livekit-client@2.22.2(@types/dom-mediacapture-record@1.0.22):
+  livekit-client@2.22.0(@types/dom-mediacapture-record@1.0.22):
     dependencies:
       '@livekit/mutex': 1.1.1
       '@livekit/protocol': 1.50.4
       '@types/dom-mediacapture-record': 1.0.22
       events: 3.3.0
-      jose: 6.2.12
+      jose: 6.2.10
       loglevel: 1.9.2
-      machina: 7.0.1
       sdp-transform: 2.15.0
       tslib: 2.8.1
       typed-emitter: 2.1.0
@@ -10258,8 +10253,6 @@ snapshots:
 
   lz-string@1.5.0: {}
 
-  machina@7.0.1: {}
-
   magic-string@0.30.21:
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.5
@@ -10291,12 +10284,12 @@ snapshots:
       content-type: 3.0.0
       loglevel: 1.9.2
       matrix-events-sdk: 0.0.1
-      matrix-widget-api: 1.19.0
+      matrix-widget-api: 1.18.0
       p-retry: 8.0.0
       sdp-transform: 3.0.0
       unhomoglyph: 1.0.6
 
-  matrix-widget-api@1.19.0:
+  matrix-widget-api@1.18.0:
     dependencies:
       '@types/events': 3.0.3
       events: 3.3.0

src/livekit/openIDSFU.test.ts

@@ -79,8 +79,14 @@ describe("getSFUConfigWithOpenID", () => {
       );
     } catch (ex: unknown) {
       expect(ex).toBeInstanceOf(FailToGetOpenIdToken);
-      expect((ex as FailToGetOpenIdToken).cause).toBeInstanceOf(MatrixError);
-      const mxError = (ex as Error).cause as MatrixError;
+      // The cause is a wrapper naming the operation we were performing; the
+      // underlying MatrixError sits behind it.
+      const context = (ex as FailToGetOpenIdToken).cause as Error;
+      expect(context.message).toEqual(
+        "Failed to get a JWT from the legacy endpoint of the MatrixRTC backend at https://sfu.example.org",
+      );
+      expect(context.cause).toBeInstanceOf(MatrixError);
+      const mxError = context.cause as MatrixError;
       expect(mxError.message).toEqual(
         "MatrixError: [500] Failed to look up user info from homeserver",
       );
@@ -216,8 +222,14 @@ describe("getSFUConfigWithOpenID", () => {
       );
     } catch (ex) {
       expect(ex).toBeInstanceOf(FailToGetOpenIdToken);
-      expect((ex as FailToGetOpenIdToken).cause).toBeInstanceOf(MatrixError);
-      const mxError = (ex as Error).cause as MatrixError;
+      // The cause is a wrapper naming the operation we were performing; the
+      // underlying MatrixError sits behind it.
+      const context = (ex as FailToGetOpenIdToken).cause as Error;
+      expect(context.message).toEqual(
+        "Failed to get a JWT from the legacy endpoint of the MatrixRTC backend at https://sfu.example.org",
+      );
+      expect(context.cause).toBeInstanceOf(MatrixError);
+      const mxError = context.cause as MatrixError;
       expect(mxError.message).toEqual(
         "MatrixError: [500] Failed to look up user info from homeserver",
       );

src/livekit/openIDSFU.ts

@@ -109,8 +109,14 @@ export async function getSFUConfigWithOpenID(
       client.getOpenIdToken(),
     );
   } catch (error) {
+    // Note that in widget mode this is the `get_openid` widget action rather
+    // than a homeserver request, so the hosting client is a likely culprit.
     throw new FailToGetOpenIdToken(
-      error instanceof Error ? error : new Error("Unknown error"),
+      new Error(
+        `Failed to get an OpenID token, needed to authenticate with the MatrixRTC backend at ${serviceUrl}` +
+          `${opts?.delayId ? " (re-authenticating to delegate delayed leave event " + opts.delayId + ")" : ""}`,
+        { cause: error },
+      ),
     );
   }
   logger?.debug("Got openID token", openIdToken);
@@ -142,7 +148,12 @@ export async function getSFUConfigWithOpenID(
       logger?.debug(`Failed fetching jwt with matrix 2.0 endpoint:`, e);
       // Make this throw a hard error in case we force the matrix2.0 endpoint.
       if (forceMatrix2Jwt) {
-        throw new NoMatrix2AuthorizationService(e as Error);
+        throw new NoMatrix2AuthorizationService(
+          new Error(
+            `Failed to get a JWT from the Matrix 2.0 endpoint of the MatrixRTC backend at ${serviceUrl}`,
+            { cause: e },
+          ),
+        );
       }
     }
   }
@@ -166,7 +177,10 @@ export async function getSFUConfigWithOpenID(
     return extractFullConfigFromToken(sfuConfig);
   } catch (ex) {
     throw new FailToGetOpenIdToken(
-      ex instanceof Error ? ex : new Error(`Unknown error ${ex}`),
+      new Error(
+        `Failed to get a JWT from the legacy endpoint of the MatrixRTC backend at ${serviceUrl}`,
+        { cause: ex },
+      ),
     );
   }
 }

src/room/GroupCallErrorBoundary.tsx

@@ -23,10 +23,10 @@ import {
 } from "@vector-im/compound-design-tokens/assets/web/icons";
 import { Button } from "@vector-im/compound-web";
 import { logger } from "matrix-js-sdk/lib/logger";
-import { MatrixError } from "matrix-js-sdk";
 
 import {
   ConnectionLostError,
+  describeErrorChain,
   ElementCallError,
   ErrorCategory,
   ErrorCode,
@@ -80,8 +80,13 @@ const ErrorPage: FC<ErrorPageProps> = ({
     });
   }
 
-  const technicalError =
-    error.cause instanceof MatrixError ? error.cause : null;
+  // Show the whole cause chain rather than just a `MatrixError` cause: the
+  // request that actually failed is often several wrappers deep, and errors
+  // that are not `MatrixError`s (widget API timeouts, LiveKit connection
+  // errors, ...) used to leave this section empty entirely. A chain of length
+  // one is just the error we already render above, so keep it hidden.
+  const errorChain = describeErrorChain(error);
+  const technicalDetails = errorChain.length > 1 ? errorChain.join("\n") : null;
 
   return (
     <FullScreenView>
@@ -119,14 +124,12 @@ const ErrorPage: FC<ErrorPageProps> = ({
             />
           )}
         </p>
-        {technicalError ? (
+        {technicalDetails ? (
           <details className={styles.technicalDetails}>
             <summary className={styles.technicalDetailsSummary}>
               {t("technical_details")}
             </summary>
-            <pre className={styles.technicalDetailsPre}>
-              {technicalError.message}
-            </pre>
+            <pre className={styles.technicalDetailsPre}>{technicalDetails}</pre>
           </details>
         ) : null}
         {actions &&
@@ -162,7 +165,13 @@ export const GroupCallErrorBoundary = ({
       const callError =
         error instanceof ElementCallError
           ? error
-          : new UnknownCallError(error instanceof Error ? error : new Error());
+          : new UnknownCallError(
+              error instanceof Error
+                ? error
+                : new Error(
+                    `Non-error value thrown during the call: ${String(error)}`,
+                  ),
+            );
       return (
         <ErrorPage
           widget={widget ?? null}

src/room/GroupCallView.tsx

@@ -179,7 +179,13 @@ export const GroupCallView: FC<Props> = ({
       ) {
         setExternalError(new StickyEventsRequiredError());
       } else {
-        setExternalError(new ConnectionLostError());
+        logger.error("MembershipManager gave up on the session", error);
+        // Keep the original error as the cause: the scheduler only tells us
+        // that it shut down, while the request that actually failed (and its
+        // errcode) lives further down the cause chain.
+        setExternalError(
+          new ConnectionLostError(error instanceof Error ? error : undefined),
+        );
       }
     },
   );

src/room/InCallView.tsx

@@ -270,7 +270,6 @@ export const InCallView: FC<InCallViewProps> = ({
   const audioParticipants = useBehavior(vm.livekitRoomItems$);
   const participantCount = useBehavior(vm.participantCount$);
   const reconnecting = useBehavior(vm.reconnecting$);
-  const screenShareError = useBehavior(vm.screenShareError$);
   const layout = useBehavior(vm.layout$);
   const edgeToEdge = useBehavior(vm.edgeToEdge$);
   const overflowing = useBehavior(vm.overflowing$);
@@ -400,21 +399,6 @@ export const InCallView: FC<InCallViewProps> = ({
       );
   }
 
-  const onDismissScreenShareToast = useCallback(
-    () => vm.dismissScreenShareError(),
-    [vm],
-  );
-  const screenShareToast = (
-    <Toast
-      onDismiss={onDismissScreenShareToast}
-      open={screenShareError !== null}
-      autoDismiss={5000}
-      modal={false}
-    >
-      {t("error.screen_share_failed")}
-    </Toast>
-  );
-
   // The reconnecting toast cannot be dismissed
   const onDismissReconnectingToast = useCallback(() => {}, []);
   // We need to use a non-modal toast to avoid trapping focus within the toast.
@@ -650,7 +634,6 @@ export const InCallView: FC<InCallViewProps> = ({
       <ReactionsAudioRenderer vm={vm} muted={muteAllAudio} />
       <RingingAudioRenderer vm={ringingVm} muted={muteAllAudio} />
       {reconnectingToast}
-      {screenShareToast}
       {earpieceOverlay}
       <ReactionsOverlay vm={vm} />
       {footer}

src/room/__snapshots__/InCallView.test.tsx.snap

@@ -171,7 +171,7 @@ exports[`InCallView > rendering > renders 1`] = `
         class="_settingsLogoContainer_20b7b4"
       >
         <button
-          aria-labelledby="_r_b_"
+          aria-labelledby="_r_8_"
           class="_icon-button_1215g_8 _settingsOnlyShowWide_20b7b4"
           data-kind="secondary"
           data-testid="settings-bottom-left"
@@ -306,7 +306,7 @@ exports[`InCallView > rendering > renders 1`] = `
         class="_buttons_20b7b4"
       >
         <button
-          aria-labelledby="_r_g_"
+          aria-labelledby="_r_d_"
           class="_button_1nw83_8 _settingsOnlyShowNarrow_20b7b4 _has-icon_1nw83_60 _icon-only_1nw83_53"
           data-kind="secondary"
           data-size="lg"
@@ -331,7 +331,7 @@ exports[`InCallView > rendering > renders 1`] = `
           aria-busy="false"
           aria-checked="false"
           aria-disabled="true"
-          aria-labelledby="_r_l_"
+          aria-labelledby="_r_i_"
           class="_button_1nw83_8 _has-icon_1nw83_60 _icon-only_1nw83_53"
           data-kind="primary"
           data-size="lg"
@@ -356,7 +356,7 @@ exports[`InCallView > rendering > renders 1`] = `
           aria-busy="false"
           aria-checked="false"
           aria-disabled="true"
-          aria-labelledby="_r_q_"
+          aria-labelledby="_r_n_"
           class="_button_1nw83_8 _has-icon_1nw83_60 _icon-only_1nw83_53"
           data-kind="primary"
           data-size="lg"
@@ -381,7 +381,7 @@ exports[`InCallView > rendering > renders 1`] = `
           aria-disabled="false"
           aria-expanded="false"
           aria-haspopup="true"
-          aria-labelledby="_r_v_"
+          aria-labelledby="_r_s_"
           class="_button_1nw83_8 _raiseHand_20b7b4 _has-icon_1nw83_60 _icon-only_1nw83_53"
           data-kind="secondary"
           data-size="lg"
@@ -404,7 +404,7 @@ exports[`InCallView > rendering > renders 1`] = `
           </svg>
         </button>
         <button
-          aria-labelledby="_r_17_"
+          aria-labelledby="_r_14_"
           class="_button_1nw83_8 _has-icon_1nw83_60 _icon-only_1nw83_53 _destructive_1nw83_110"
           data-kind="primary"
           data-size="lg"
@@ -432,8 +432,8 @@ exports[`InCallView > rendering > renders 1`] = `
         data-size="lg"
       >
         <input
-          aria-labelledby="_r_1d_"
-          name="_r_1c_"
+          aria-labelledby="_r_1a_"
+          name="_r_19_"
           type="radio"
           value="spotlight"
         />
@@ -452,9 +452,9 @@ exports[`InCallView > rendering > renders 1`] = `
           />
         </svg>
         <input
-          aria-labelledby="_r_1i_"
+          aria-labelledby="_r_1f_"
           checked=""
-          name="_r_1c_"
+          name="_r_19_"
           type="radio"
           value="grid"
         />

src/settings/rageshake.flush.test.ts

@@ -1,52 +0,0 @@
-/*
-Copyright 2026 Element Creations Ltd.
-
-SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
-Please see LICENSE in the repository root for full details.
-*/
-
-import { afterEach, expect, it, vi } from "vitest";
-
-import { init as initRageshake } from "./rageshake";
-
-afterEach(() => {
-  vi.useRealTimers();
-  vi.unstubAllGlobals();
-});
-
-it("flushes logs to IndexedDB periodically without an explicit flush", async () => {
-  vi.useFakeTimers();
-  const add = vi.fn();
-  const txn = {
-    oncomplete: undefined as (() => void) | undefined,
-    onerror: undefined,
-    objectStore: (name: string) =>
-      name === "logs"
-        ? {
-            add: (entry: unknown): void => {
-              add(entry);
-              queueMicrotask(() => txn.oncomplete?.());
-            },
-          }
-        : { put: vi.fn() },
-  };
-  const open = (): unknown => {
-    const req = {
-      result: { transaction: () => txn },
-      onsuccess: undefined as (() => void) | undefined,
-    };
-    queueMicrotask(() => req.onsuccess?.());
-    return req;
-  };
-  vi.stubGlobal("indexedDB", { open });
-
-  await initRageshake();
-  global.mx_rage_logger.log(1, "test", "hello from the buffer");
-  expect(add).not.toHaveBeenCalled();
-
-  await vi.advanceTimersByTimeAsync(2000);
-  expect(add).toHaveBeenCalledOnce();
-  expect(add.mock.calls[0][0]).toMatchObject({
-    lines: expect.stringContaining("hello from the buffer"),
-  });
-});

src/settings/rageshake.ts

@@ -204,13 +204,10 @@ class IndexedDBLogStore {
   // Throttled function to flush logs. We use throttle rather
   // than debounce as we want logs to be written regularly, otherwise
   // if there's a constant stream of logging, we'd never write anything.
-  private throttledFlush = throttle(
-    () => {
-      this.flush().catch((e) => logger.error("Failed to flush logs", e));
-    },
-    MAX_FLUSH_INTERVAL_MS,
-    { leading: false, trailing: true },
-  );
+  private throttledFlush = throttle(() => this.flush, MAX_FLUSH_INTERVAL_MS, {
+    leading: false,
+    trailing: true,
+  });
 
   /**
    * Flush logs to disk.

src/state/CallViewModel/CallViewModel.ts

@@ -267,11 +267,6 @@ export interface CallViewModel {
    * Whether we are sharing our screen.
    */
   sharingScreen$: Behavior<boolean>;
-  /**
-   * The last error from toggling screen sharing, until dismissed.
-   */
-  screenShareError$: Behavior<Error | null>;
-  dismissScreenShareError: () => void;
 
   // UI interactions
   /**
@@ -1863,8 +1858,6 @@ export function createCallViewModel$(
     reconnecting$: localMembership.reconnecting$,
     livekitRoomItems$,
     connected$: localMembership.connected$,
-    screenShareError$: localMembership.screenShareError$,
-    dismissScreenShareError: localMembership.dismissScreenShareError,
   };
 }
 

src/state/CallViewModel/localMember/LocalMember.test.ts

@@ -31,7 +31,6 @@ import {
   flushPromises,
   mockConfig,
   mockLivekitRoom,
-  mockLocalParticipant,
   mockMuteStates,
   withTestScheduler,
   ownMemberMock,
@@ -42,7 +41,6 @@ import {
   enterRTCSession,
   PublishState,
   TrackState,
-  watchScreenShareToggle,
 } from "./LocalMember";
 import {
   FailToGetOpenIdToken,
@@ -70,31 +68,6 @@ vi.mock("@livekit/components-core", () => ({
     .mockReturnValue(of({ isScreenShareEnabled: false })),
 }));
 
-describe("watchScreenShareToggle", () => {
-  it("reports nothing when the toggle completes", async () => {
-    const onError = vi.fn();
-    watchScreenShareToggle(Promise.resolve(), true, logger, onError);
-    await flushPromises();
-    expect(onError).not.toHaveBeenCalled();
-  });
-
-  it("reports failures other than the user cancelling", async () => {
-    const onError = vi.fn();
-    const e = new Error("NotReadableError");
-    watchScreenShareToggle(Promise.reject(e), true, logger, onError);
-    await flushPromises();
-    expect(onError).toHaveBeenCalledWith(e);
-  });
-
-  it("does not report the user cancelling the picker", async () => {
-    const onError = vi.fn();
-    const cancelled = new DOMException("Permission denied", "NotAllowedError");
-    watchScreenShareToggle(Promise.reject(cancelled), true, logger, onError);
-    await flushPromises();
-    expect(onError).not.toHaveBeenCalled();
-  });
-});
-
 describe("LocalMembership", () => {
   describe("enterRTCSession", () => {
     it("It joins the correct Session", () => {
@@ -881,98 +854,4 @@ describe("LocalMembership", () => {
       scope.end();
     });
   });
-
-  describe("toggleScreenSharing", () => {
-    let originalMediaDevices: MediaDevices | undefined;
-
-    beforeAll(() => {
-      mockConfig();
-      // Screen sharing is only offered when getDisplayMedia is available.
-      originalMediaDevices = navigator.mediaDevices;
-      Object.defineProperty(navigator, "mediaDevices", {
-        configurable: true,
-        value: { getDisplayMedia: vi.fn() },
-      });
-    });
-
-    afterAll(() => {
-      Object.defineProperty(navigator, "mediaDevices", {
-        configurable: true,
-        value: originalMediaDevices,
-      });
-    });
-
-    const createMembershipWithConnection = (
-      connection: Connection | null,
-    ): {
-      scope: ObservableScope;
-      localMembership: ReturnType<typeof createLocalMembership$>;
-    } => {
-      const scope = new ObservableScope();
-      const connectionManagerData = new ConnectionManagerData();
-      if (connection) connectionManagerData.add(connection, []);
-      const localMembership = createLocalMembership$({
-        scope,
-        ...defaultCreateLocalMemberValues,
-        connectionManager: {
-          connectionManagerData$: constant(new Epoch(connectionManagerData)),
-        },
-        localTransport$: new BehaviorSubject({
-          advertised$: new BehaviorSubject(aTransport),
-          active$: new BehaviorSubject(aTransportWithSFUConfig),
-        }),
-      });
-      return { scope, localMembership };
-    };
-
-    it("surfaces a failure and clears it on dismiss", async () => {
-      const error = new Error("NotReadableError");
-      const setScreenShareEnabled = vi.fn().mockRejectedValue(error);
-      const connection = {
-        state$: constant(ConnectionState.LivekitConnected),
-        transport: aTransport,
-        livekitRoom: mockLivekitRoom({
-          localParticipant: mockLocalParticipant({
-            isScreenShareEnabled: false,
-            setScreenShareEnabled,
-          }),
-        }),
-      } as unknown as Connection;
-      const { scope, localMembership } =
-        createMembershipWithConnection(connection);
-      await flushPromises();
-
-      expect(localMembership.toggleScreenSharing).not.toBeNull();
-      expect(localMembership.screenShareError$.value).toBeNull();
-
-      localMembership.toggleScreenSharing!();
-      await flushPromises();
-
-      expect(setScreenShareEnabled).toHaveBeenCalledWith(
-        true,
-        expect.any(Object),
-        undefined,
-      );
-      expect(localMembership.screenShareError$.value).toBe(error);
-
-      localMembership.dismissScreenShareError();
-      expect(localMembership.screenShareError$.value).toBeNull();
-
-      scope.end();
-    });
-
-    it("does nothing when there is no local participant", async () => {
-      // No connection means participant$ never resolves to a participant.
-      const { scope, localMembership } = createMembershipWithConnection(null);
-      await flushPromises();
-
-      expect(localMembership.toggleScreenSharing).not.toBeNull();
-      localMembership.toggleScreenSharing!();
-      await flushPromises();
-
-      expect(localMembership.screenShareError$.value).toBeNull();
-
-      scope.end();
-    });
-  });
 });

src/state/CallViewModel/localMember/LocalMember.ts

@@ -196,11 +196,6 @@ export const createLocalMembership$ = ({
    * Callback to toggle screen sharing. If null, screen sharing is not possible.
    */
   toggleScreenSharing: (() => void) | null;
-  /**
-   * The last error from toggling screen sharing, until dismissed.
-   */
-  screenShareError$: Behavior<Error | null>;
-  dismissScreenShareError: () => void;
   // tracks$: Behavior<LocalTrack[]>;
   participant$: Behavior<LocalParticipant | null>;
   connection$: Behavior<Connection | null>;
@@ -711,7 +706,6 @@ export const createLocalMembership$ = ({
     ),
   );
 
-  const screenShareError$ = new BehaviorSubject<Error | null>(null);
   let toggleScreenSharing: (() => void) | null = null;
   if (
     "getDisplayMedia" in (navigator.mediaDevices ?? {}) &&
@@ -783,18 +777,13 @@ export const createLocalMembership$ = ({
       // We also allow screen sharing to be toggled even if the connection
       // is still initializing or publishing tracks, because there's no
       // technical reason to disallow this. LiveKit will publish if it can.
-      const participant = participant$.value;
-      if (!participant) return;
-      watchScreenShareToggle(
-        participant.setScreenShareEnabled(
+      participant$.value
+        ?.setScreenShareEnabled(
           targetScreenshareState,
           screenshareSettings,
           publishOptions,
-        ),
-        targetScreenshareState,
-        logger,
-        (e) => screenShareError$.next(e),
-      );
+        )
+        .catch(logger.error);
     };
   }
 
@@ -813,44 +802,11 @@ export const createLocalMembership$ = ({
     ),
     sharingScreen$,
     toggleScreenSharing,
-    screenShareError$,
-    dismissScreenShareError: () => screenShareError$.next(null),
     connection$: localConnection$,
     internalLoggerRef: logger,
   };
 };
 
-/**
- * Logs the outcome of a screen share toggle and reports failures.
- *
- * getDisplayMedia may legitimately take a long time (the user is choosing
- * what to share) or never settle at all, so nothing is inferred from silence:
- * the request and its completion are logged with the elapsed time so that a
- * hang is visible in the logs, and only an explicit rejection is reported.
- *
- * The user cancelling the picker rejects with a NotAllowedError; that is
- * logged but not reported.
- */
-export function watchScreenShareToggle(
-  toggle: Promise<unknown>,
-  enable: boolean,
-  logger: Logger,
-  onError: (e: Error) => void,
-): void {
-  const what = `Screen share ${enable ? "start" : "stop"}`;
-  const started = Date.now();
-  const elapsed = (): string => `${Date.now() - started} ms`;
-  logger.info(`${what} requested`);
-  toggle.then(
-    () => logger.info(`${what} completed in ${elapsed()}`),
-    (e: unknown) => {
-      logger.error(`${what} failed after ${elapsed()}:`, e);
-      if (e instanceof DOMException && e.name === "NotAllowedError") return;
-      onError(e instanceof Error ? e : new Error(String(e)));
-    },
-  );
-}
-
 export function observeSharingScreen$(p: Participant): Observable<boolean> {
   return observeParticipantEvents(
     p,

src/state/CallViewModel/localMember/LocalTransport.ts

@@ -179,7 +179,11 @@ export const createLocalTransport$ = ({
           `Failed to authenticate to transport ${transport.livekit_service_url}`,
           e,
         );
-        throw mapAuthErrorToUserFriendlyError(e);
+        throw mapAuthErrorToUserFriendlyError(
+          e,
+          transport.livekit_service_url,
+          delayId,
+        );
       }
     }),
   );
@@ -258,16 +262,26 @@ async function doOpenIdAndJWTFromUrl(
   };
 }
 
-function mapAuthErrorToUserFriendlyError(e: unknown): Error {
+function mapAuthErrorToUserFriendlyError(
+  e: unknown,
+  serviceUrl: string,
+  delayId: string | null,
+): Error {
   if (
     e instanceof FailToGetOpenIdToken ||
     e instanceof NoMatrix2AuthorizationService
   ) {
-    // rethrow as is
+    // Already carries its own context, rethrow as is.
     return e;
   }
-  // Catch others and rethrow as FailToGetOpenIdToken that has user friendly message.
+  // Catch others and rethrow as FailToGetOpenIdToken that has user friendly
+  // message. Record what we were doing, since this branch is reached by
+  // anything unexpected and otherwise leaves no trace of it.
   return new FailToGetOpenIdToken(
-    e instanceof Error ? e : new Error(String(e)),
+    new Error(
+      `Unexpected error while authenticating with the MatrixRTC backend at ${serviceUrl}` +
+        `${delayId ? ` (re-authenticating to delegate delayed leave event ${delayId})` : ""}`,
+      { cause: e },
+    ),
   );
 }

src/state/CallViewModel/localMember/RtcTransportAutoDiscovery.ts

@@ -85,7 +85,10 @@ export class RtcTransportAutoDiscovery {
         );
       }
     } catch (ex) {
-      this.logger.info(`Failed to use getRTCTransports end point: ${ex}`);
+      // Expected against homeservers without MSC4143, so this is not a
+      // warning, but pass the error itself so the stack and any errcode
+      // survive into the logs rather than being flattened into a string.
+      this.logger.info("Failed to use getRTCTransports end point", ex);
     }
     return null;
   }

src/state/CallViewModel/remoteMembers/Connection.test.ts

@@ -19,17 +19,14 @@ import {
 import {
   type LocalParticipant,
   type RemoteParticipant,
-  type RemoteTrack,
-  type RemoteTrackPublication,
   type Room as LivekitRoom,
   RoomEvent,
-  Track,
   ConnectionState as LivekitConnectionState,
 } from "livekit-client";
 import fetchMock from "fetch-mock";
 import EventEmitter from "events";
 import { type IOpenIDToken } from "matrix-js-sdk";
-import { logger, type Logger } from "matrix-js-sdk/lib/logger";
+import { logger } from "matrix-js-sdk/lib/logger";
 import { type LivekitTransportConfig } from "matrix-js-sdk/lib/matrixrtc";
 
 import {
@@ -40,6 +37,7 @@ import {
 import { ObservableScope } from "../../ObservableScope.ts";
 import { type OpenIDClientParts } from "../../../livekit/openIDSFU.ts";
 import {
+  describeErrorChain,
   ElementCallError,
   FailToGetOpenIdToken,
 } from "../../../utils/errors.ts";
@@ -287,7 +285,9 @@ describe("Start connection states", () => {
       capturedState instanceof ElementCallError &&
       capturedState.cause instanceof Error
     ) {
-      expect(capturedState.cause.message).toContain(
+      // The homeserver error is wrapped in a context error naming the
+      // operation that failed, so assert against the whole cause chain.
+      expect(describeErrorChain(capturedState).join("\n")).toContain(
         "Failed to look up user info from homeserver",
       );
       expect(connection.transport.livekit_alias).toEqual(
@@ -512,79 +512,6 @@ describe("remote participants", () => {
   });
 });
 
-describe("remote track logging", () => {
-  it("logs remote participant and track events on the connection logger", () => {
-    setupTest();
-    const info = vi.fn();
-    const testLogger = {
-      getChild: (): unknown => testLogger,
-      info,
-      debug: vi.fn(),
-      warn: vi.fn(),
-      error: vi.fn(),
-    } as unknown as Logger;
-    new Connection(
-      {
-        client,
-        roomId: ROOM_ID,
-        transport: livekitFocus,
-        scope: testScope,
-        ownMembershipIdentity: ownMemberMock,
-        livekitRoomFactory: () => fakeLivekitRoom,
-      },
-      testLogger,
-    );
-    info.mockClear(); // drop the constructor log line
-
-    const bob = mockRemoteParticipant({
-      identity: "@bob:example.org:DEV111",
-      sid: "PA_bob",
-    });
-    const pub = {
-      kind: "audio",
-      source: "microphone",
-      trackSid: "TR_mic",
-      isMuted: false,
-    } as unknown as RemoteTrackPublication;
-    const messages = (): string[] => info.mock.calls.map((c) => c[0] as string);
-
-    fakeLivekitRoom.emit(RoomEvent.ParticipantConnected, bob);
-    fakeLivekitRoom.emit(
-      RoomEvent.TrackSubscribed,
-      {} as RemoteTrack,
-      pub,
-      bob,
-    );
-    fakeLivekitRoom.emit(RoomEvent.TrackMuted, pub, bob);
-    fakeLivekitRoom.emit(
-      RoomEvent.TrackStreamStateChanged,
-      pub,
-      Track.StreamState.Paused,
-      bob,
-    );
-    expect(messages()).toEqual([
-      "Participant connected: @bob:example.org:DEV111 (PA_bob)",
-      "Subscribed: audio microphone TR_mic of @bob:example.org:DEV111 muted=false",
-      "Muted: audio microphone TR_mic of @bob:example.org:DEV111",
-      "Stream paused: audio microphone TR_mic of @bob:example.org:DEV111",
-    ]);
-
-    // Local mute events are already logged by the Publisher
-    fakeLivekitRoom.emit(RoomEvent.TrackMuted, pub, {
-      ...fakeLocalParticipant,
-      isLocal: true,
-    } as unknown as LocalParticipant);
-    expect(messages().filter((m) => m.startsWith("Muted"))).toHaveLength(1);
-
-    // Listeners are removed when the scope ends
-    testScope.end();
-    fakeLivekitRoom.emit(RoomEvent.ParticipantDisconnected, bob);
-    expect(
-      messages().filter((m) => m.startsWith("Participant disconnected")),
-    ).toHaveLength(0);
-  });
-});
-
 //
 // NOT USED ANYMORE ?
 //

src/state/CallViewModel/remoteMembers/Connection.ts

@@ -13,14 +13,8 @@ import {
 import {
   ConnectionError,
   ConnectionErrorReason,
-  type Participant,
   type RemoteParticipant,
-  type RemoteTrackPublication,
   type Room as LivekitRoom,
-  RoomEvent,
-  type SubscriptionError,
-  type Track,
-  type TrackPublication,
 } from "livekit-client";
 import { type LivekitTransportConfig } from "matrix-js-sdk/lib/matrixrtc";
 import { BehaviorSubject, map } from "rxjs";
@@ -170,7 +164,6 @@ export class Connection {
       // Only tracks remote participants
       connectedParticipantsObserver(this.livekitRoom),
     );
-    this.logRemoteTrackEvents();
 
     scope.onEnd(() => {
       this.logger.info(`Connection scope ended, stopping connection`);
@@ -178,87 +171,6 @@ export class Connection {
     });
   }
 
-  /**
-   * Logs the lifecycle of remote participants and their tracks as seen by
-   * livekit-client, so that rageshakes show what a tile should have been
-   * rendering (published, subscribed, muted, paused) for each remote member.
-   */
-  private logRemoteTrackEvents(): void {
-    const room = this.livekitRoom;
-    const log = this.logger.getChild("[RemoteTracks]");
-    const track = (pub: TrackPublication, p: Participant): string =>
-      `${pub.kind} ${pub.source} ${pub.trackSid} of ${p.identity}`;
-
-    const onParticipantConnected = (p: RemoteParticipant): void =>
-      log.info(`Participant connected: ${p.identity} (${p.sid})`);
-    const onParticipantDisconnected = (p: RemoteParticipant): void =>
-      log.info(`Participant disconnected: ${p.identity} (${p.sid})`);
-    const onTrackPublished = (
-      pub: RemoteTrackPublication,
-      p: RemoteParticipant,
-    ): void => log.info(`Published: ${track(pub, p)} muted=${pub.isMuted}`);
-    const onTrackUnpublished = (
-      pub: RemoteTrackPublication,
-      p: RemoteParticipant,
-    ): void => log.info(`Unpublished: ${track(pub, p)}`);
-    const onTrackSubscribed = (
-      _t: Track,
-      pub: RemoteTrackPublication,
-      p: RemoteParticipant,
-    ): void => log.info(`Subscribed: ${track(pub, p)} muted=${pub.isMuted}`);
-    const onTrackUnsubscribed = (
-      _t: Track,
-      pub: RemoteTrackPublication,
-      p: RemoteParticipant,
-    ): void => log.info(`Unsubscribed: ${track(pub, p)}`);
-    const onTrackSubscriptionFailed = (
-      trackSid: string,
-      p: RemoteParticipant,
-      reason?: SubscriptionError,
-    ): void =>
-      log.warn(
-        `Subscription failed: ${trackSid} of ${p.identity} reason=${reason}`,
-      );
-    // Mute events also fire for the local participant, which the Publisher
-    // already logs.
-    const onTrackMuted = (pub: TrackPublication, p: Participant): void => {
-      if (!p.isLocal) log.info(`Muted: ${track(pub, p)}`);
-    };
-    const onTrackUnmuted = (pub: TrackPublication, p: Participant): void => {
-      if (!p.isLocal) log.info(`Unmuted: ${track(pub, p)}`);
-    };
-    const onTrackStreamStateChanged = (
-      pub: RemoteTrackPublication,
-      state: Track.StreamState,
-      p: RemoteParticipant,
-    ): void => log.info(`Stream ${state}: ${track(pub, p)}`);
-
-    room
-      .on(RoomEvent.ParticipantConnected, onParticipantConnected)
-      .on(RoomEvent.ParticipantDisconnected, onParticipantDisconnected)
-      .on(RoomEvent.TrackPublished, onTrackPublished)
-      .on(RoomEvent.TrackUnpublished, onTrackUnpublished)
-      .on(RoomEvent.TrackSubscribed, onTrackSubscribed)
-      .on(RoomEvent.TrackUnsubscribed, onTrackUnsubscribed)
-      .on(RoomEvent.TrackSubscriptionFailed, onTrackSubscriptionFailed)
-      .on(RoomEvent.TrackMuted, onTrackMuted)
-      .on(RoomEvent.TrackUnmuted, onTrackUnmuted)
-      .on(RoomEvent.TrackStreamStateChanged, onTrackStreamStateChanged);
-    this.scope.onEnd(() => {
-      room
-        .off(RoomEvent.ParticipantConnected, onParticipantConnected)
-        .off(RoomEvent.ParticipantDisconnected, onParticipantDisconnected)
-        .off(RoomEvent.TrackPublished, onTrackPublished)
-        .off(RoomEvent.TrackUnpublished, onTrackUnpublished)
-        .off(RoomEvent.TrackSubscribed, onTrackSubscribed)
-        .off(RoomEvent.TrackUnsubscribed, onTrackUnsubscribed)
-        .off(RoomEvent.TrackSubscriptionFailed, onTrackSubscriptionFailed)
-        .off(RoomEvent.TrackMuted, onTrackMuted)
-        .off(RoomEvent.TrackUnmuted, onTrackUnmuted)
-        .off(RoomEvent.TrackStreamStateChanged, onTrackStreamStateChanged);
-    });
-  }
-
   /**
    * Starts the connection.
    *

src/state/CallViewModel/remoteMembers/ConnectionManager.test.ts

@@ -14,7 +14,7 @@ import { logger } from "matrix-js-sdk/lib/logger";
 import { Epoch, mapEpoch, ObservableScope } from "../../ObservableScope.ts";
 import {
   createConnectionManager$,
-  ConnectionManagerData,
+  type ConnectionManagerData,
 } from "./ConnectionManager.ts";
 import { type ConnectionFactory } from "./ConnectionFactory.ts";
 import { type Connection } from "./Connection.ts";
@@ -203,24 +203,6 @@ describe("connections$ stream", () => {
   });
 });
 
-describe("ConnectionManagerData", () => {
-  test("warns when a second connection to the same URL is merged", () => {
-    const warn = vi.spyOn(logger, "warn").mockImplementation(() => {});
-    const data = new ConnectionManagerData(logger);
-    const connection = { transport: TRANSPORT_1 } as unknown as Connection;
-    const p = (identity: string): RemoteParticipant =>
-      ({ identity }) as unknown as RemoteParticipant;
-    data.add(connection, [p("a")]);
-    data.add({ ...connection } as Connection, [p("b")]);
-    expect(warn).toHaveBeenCalledWith(
-      expect.stringContaining(
-        "second connection to https://lk.example.org: existing [a], adding [b]",
-      ),
-    );
-    expect(data.getParticipantsForTransport(TRANSPORT_1)).toHaveLength(2);
-  });
-});
-
 describe("connectionManagerData$ stream", () => {
   // Used in test to control fake connections' remoteParticipants$ streams
   let fakeRemoteParticipantsStreams: Map<string, Behavior<RemoteParticipant[]>>;

src/state/CallViewModel/remoteMembers/ConnectionManager.ts

@@ -30,7 +30,7 @@ export class ConnectionManagerData {
     { connection: Connection; participants: RemoteParticipant[] }
   > = new Map();
 
-  public constructor(private readonly logger?: Logger) {}
+  public constructor() {}
 
   public add(connection: Connection, participants: RemoteParticipant[]): void {
     const key = this.getKey(connection.transport);
@@ -38,11 +38,6 @@ export class ConnectionManagerData {
     if (!existing) {
       this.store.set(key, { connection, participants });
     } else {
-      // Transports are deduplicated by URL upstream, so this should never
-      // happen; if it does, members may be matched against the wrong room.
-      this.logger?.warn(
-        `Merging participants from a second connection to ${key}: existing [${existing.participants.map((p) => p.identity).join(", ")}], adding [${participants.map((p) => p.identity).join(", ")}]`,
-      );
       existing.participants.push(...participants);
     }
   }
@@ -244,7 +239,7 @@ export function createConnectionManager$({
                 lists.reduce((data, { connection, participants }) => {
                   data.add(connection, participants);
                   return data;
-                }, new ConnectionManagerData(logger)),
+                }, new ConnectionManagerData()),
                 epoch,
               ),
           ),

src/state/CallViewModel/remoteMembers/MatrixLivekitMembers.test.ts

@@ -5,8 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-import { describe, test, expect, beforeEach, afterEach, vi } from "vitest";
-import { logger } from "matrix-js-sdk/lib/logger";
+import { describe, test, expect, beforeEach, afterEach } from "vitest";
 import {
   type CallMembership,
   type LivekitTransport,
@@ -78,7 +77,6 @@ function epochMeWith$<T, U>(
 }
 
 test("should signal participant not yet connected to livekit", async () => {
-  const info = vi.spyOn(logger, "info");
   const mockedMemberships$ = new BehaviorSubject([bobMembership]);
   const mockConnectionManagerData$ = new BehaviorSubject(
     new ConnectionManagerData(),
@@ -110,9 +108,6 @@ test("should signal participant not yet connected to livekit", async () => {
       return true;
     },
   );
-  expect(info).toHaveBeenCalledWith(
-    "[RemoteMatrixLivekitMembers] @bob:example.org:DEV000: LiveKit participant missing on no connection",
-  );
 });
 
 // Helper to create epoch'ed memberships$ and membershipsWithTransport$ from memberships observable.

src/state/CallViewModel/remoteMembers/MatrixLivekitMembers.ts

@@ -11,7 +11,6 @@ import {
   type LivekitTransportConfig,
 } from "matrix-js-sdk/lib/matrixrtc";
 import { combineLatest, filter, map } from "rxjs";
-import { logger } from "matrix-js-sdk/lib/logger";
 
 import { type Behavior } from "../../Behavior";
 import { type IConnectionManager } from "./ConnectionManager";
@@ -111,17 +110,13 @@ export function createRemoteMatrixLivekitMembers$({
             const participants = transport
               ? managerData.getParticipantsForTransport(transport)
               : [];
-            const matches = participants.filter(
-              (p) => p.identity == membership.rtcBackendIdentity,
-            );
-            const participant = matches[0] ?? null;
+            const participant =
+              participants.find(
+                (p) => p.identity == membership.rtcBackendIdentity,
+              ) ?? null;
             const connection = transport
               ? managerData.getConnectionForTransport(transport)
               : null;
-            if (matches.length > 1)
-              logger.warn(
-                `[RemoteMatrixLivekitMembers] ${membership.rtcBackendIdentity}: ${matches.length} LiveKit participants match (sids ${matches.map((p) => p.sid).join(", ")}), using ${participant?.sid}`,
-              );
 
             yield {
               // This could just be the backend identity without the other keys.
@@ -138,16 +133,8 @@ export function createRemoteMatrixLivekitMembers$({
           }
         },
         // Each update where the key of the generator array do not change will result in updates to the `data$` behavior.
-        (scope, data$, userId, _deviceId, _memberId, rtcBackendIdentity) => {
+        (scope, data$, userId, _deviceId, _memberId, _rtcBackendIdentity) => {
           const { participant$, ...rest } = scope.splitBehavior(data$);
-          // Log whether the member could be matched to a LiveKit participant,
-          // since a tile shows "waiting for media" for as long as it cannot.
-          participant$.pipe(scope.bind()).subscribe((p) => {
-            const url = data$.value.connection?.transport.livekit_service_url;
-            logger.info(
-              `[RemoteMatrixLivekitMembers] ${rtcBackendIdentity}: LiveKit participant ${p ? `matched (${p.sid})` : "missing"} on ${url ?? "no connection"}`,
-            );
-          });
           // will only get called once per backend identity.
           // updates to data$ and as a result to displayName$ and mxcAvatarUrl$ are more frequent.
           return {

src/state/ObservableScope.test.ts

@@ -16,7 +16,7 @@ import {
   ObservableScope,
   trackEpoch,
 } from "./ObservableScope";
-import { testScope, withTestScheduler } from "../utils/test";
+import { withTestScheduler } from "../utils/test";
 
 describe("Epoch", () => {
   it("should map the value correctly", () => {
@@ -87,7 +87,7 @@ describe("Epoch", () => {
   });
 
   it("behavior test", () => {
-    const scope = testScope();
+    const scope = new ObservableScope();
     const s$ = new Subject();
     const behavior$ = scope.behavior(s$, 0);
     behavior$.subscribe((value) => {
@@ -115,7 +115,7 @@ describe("Reconcile", () => {
 
   it("should wait clean up before processing next", async () => {
     vi.useFakeTimers();
-    const scope = testScope();
+    const scope = new ObservableScope();
     const behavior$ = new BehaviorSubject<number>(0);
 
     const setup = vi.fn().mockImplementation(async () => await sleep(100));
@@ -149,7 +149,7 @@ describe("Reconcile", () => {
 
   it("should skip intermediates values that are not setup", async () => {
     vi.useFakeTimers();
-    const scope = testScope();
+    const scope = new ObservableScope();
     const behavior$ = new BehaviorSubject<number>(0);
 
     const setup = vi
@@ -194,7 +194,7 @@ describe("Reconcile", () => {
 
   it("should wait for setup to complete before starting cleanup", async () => {
     vi.useFakeTimers();
-    const scope = testScope();
+    const scope = new ObservableScope();
     const behavior$ = new BehaviorSubject<number>(0);
 
     const setup = vi
@@ -237,57 +237,3 @@ describe("Reconcile", () => {
     expect(setup).toHaveBeenCalledWith(1);
   });
 });
-
-describe("behavior", () => {
-  it("warns with the tag and nesting depth, logging each new depth once", () => {
-    const warn = vi.spyOn(logger, "warn").mockImplementation(() => {});
-    const scope = testScope();
-    const source$ = new Subject<number>();
-    const behavior$ = scope.behavior(source$, 0, "tagged");
-    // Re-enter once on value 1 (depth 2), then a nested re-entry on value 2
-    // (depth 3), which is the shape needed to strand a middle subscriber.
-    behavior$.subscribe((v) => {
-      if (v === 1) source$.next(2);
-    });
-    behavior$.subscribe((v) => {
-      if (v === 2) source$.next(3);
-    });
-    const seen: number[] = [];
-    behavior$.subscribe((v) => seen.push(v));
-
-    source$.next(1);
-
-    const messages = warn.mock.calls.map((c) => c[0] as string);
-    expect(messages).toEqual([
-      expect.stringContaining("Behavior (tagged) re-entered at depth 2"),
-      expect.stringContaining("Behavior (tagged) re-entered at depth 3"),
-    ]);
-    warn.mock.calls.forEach((c) => expect(c[1]).toEqual(expect.any(String)));
-    // The behavior settles on the newest value while the last subscriber is
-    // left stranded on the oldest.
-    expect(behavior$.value).toBe(3);
-    expect(seen.at(-1)).toBe(1);
-  });
-
-  it("warns when the scope is ended while a behavior is mid-delivery", () => {
-    const warn = vi.spyOn(logger, "warn").mockImplementation(() => {});
-    const scope = new ObservableScope();
-    const source$ = new Subject<number>();
-    const behavior$ = scope.behavior(source$, 0);
-    behavior$.subscribe((v) => {
-      if (v === 1) scope.end();
-    });
-    // A derived behavior is bound to the scope, so ending the scope
-    // mid-delivery unsubscribes it before the value reaches it.
-    const derived$ = scope.behavior(behavior$);
-
-    source$.next(1);
-
-    expect(warn).toHaveBeenCalledWith(
-      expect.stringContaining("Scope ended while 1 of its behaviors"),
-      expect.any(String),
-    );
-    expect(behavior$.value).toBe(1);
-    expect(derived$.value).toBe(0);
-  });
-});

src/state/ObservableScope.ts

@@ -20,8 +20,6 @@ import {
   takeUntil,
 } from "rxjs";
 
-import { logger } from "matrix-js-sdk/lib/logger";
-
 import { type Behavior } from "./Behavior";
 
 type MonoTypeOperator = <T>(o: Observable<T>) => Observable<T>;
@@ -36,12 +34,6 @@ const nothing = Symbol("nothing");
  * A scope which limits the execution lifetime of its bound Observables.
  */
 export class ObservableScope {
-  /**
-   * Number of this scope's behaviors currently mid-delivery. Used to detect a
-   * scope being torn down synchronously from within one of its own emissions.
-   */
-  private delivering = 0;
-
   private readonly ended$ = new BehaviorSubject(false);
 
   private readonly bindImpl: MonoTypeOperator = takeUntil(
@@ -74,9 +66,6 @@ export class ObservableScope {
   public behavior<T>(
     setValue$: Observable<T>,
     initialValue: T | typeof nothing = nothing,
-    // An optional label used only in the re-entrancy warning below, so that a
-    // torn behavior can be identified from a rageshake.
-    tag?: string,
   ): Behavior<T> {
     const subject$ = new BehaviorSubject(initialValue);
     // Push values from the Observable into the BehaviorSubject.
@@ -84,37 +73,11 @@ export class ObservableScope {
     // they will no longer re-emit their current value upon subscription. We want
     // to support Observables that complete (for example `of({})`), so we have to
     // take care to not propagate the completion event.
-    // If a subscriber synchronously causes this same behavior to emit again,
-    // rxjs delivers the nested value to every subscriber first and then
-    // resumes delivering the outer (older) value to the remaining subscribers,
-    // leaving them permanently out of sync with the others. A single such
-    // re-entry can only strand a contiguous run of subscribers; stranding a
-    // subscriber in the middle of the list needs a nested (deeper) re-entry, so
-    // we report the depth and log each new depth (with a stack trace) rather
-    // than only the first occurrence, to make a nested re-entry visible.
-    let depth = 0;
-    let maxReportedDepth = 1;
     setValue$.pipe(this.bind(), distinctUntilChanged()).subscribe({
-      next: (value) => {
-        if (depth > 0 && depth + 1 > maxReportedDepth) {
-          maxReportedDepth = depth + 1;
-          logger.warn(
-            `Behavior${tag ? ` (${tag})` : ""} re-entered at depth ${
-              depth + 1
-            } while delivering a value; later subscribers will be left with a stale value`,
-            new Error().stack,
-          );
-        }
-        depth++;
-        this.delivering++;
-        try {
-          subject$.next(value);
-        } finally {
-          depth--;
-          this.delivering--;
-        }
+      next(value) {
+        subject$.next(value);
       },
-      error: (err: unknown) => {
+      error(err: unknown) {
         subject$.error(err);
       },
     });
@@ -127,11 +90,6 @@ export class ObservableScope {
    * Ends the scope, causing any bound Observables to complete.
    */
   public end(): void {
-    if (this.delivering > 0)
-      logger.warn(
-        `Scope ended while ${this.delivering} of its behaviors were still delivering a value; later subscribers will be left with a stale value`,
-        new Error().stack,
-      );
     this.ended$.next(true);
   }
 
@@ -213,11 +171,7 @@ export class ObservableScope {
     return Object.fromEntries(
       Object.keys(input$.value).map((key) => [
         `${key}$`,
-        this.behavior(
-          input$.pipe(map((input) => input[key as keyof T])),
-          nothing,
-          key,
-        ),
+        this.behavior(input$.pipe(map((input) => input[key as keyof T]))),
       ]),
     ) as SplitBehavior<T>;
   }

src/state/media/RemoteUserMediaViewModel.ts

@@ -8,7 +8,6 @@ Please see LICENSE in the repository root for full details.
 
 import { type RemoteParticipant } from "livekit-client";
 import { combineLatest, map, of, switchMap } from "rxjs";
-import { logger } from "matrix-js-sdk/lib/logger";
 
 import { type Behavior } from "../Behavior";
 import { createVolumeControls, type VolumeControls } from "../VolumeControls";
@@ -46,20 +45,6 @@ export function createRemoteUserMedia(
     statsType: "inbound-rtp",
   });
 
-  const waitingForMedia$ = scope.behavior(
-    combineLatest(
-      [inputs.livekitRoom$, inputs.participant$],
-      (livekitRoom, participant) =>
-        // If livekitRoom is undefined, the user is not attempting to publish on
-        // any transport and so we shouldn't expect a participant. (They might
-        // be a subscribe-only bot for example.)
-        livekitRoom !== undefined && participant === null,
-    ),
-  );
-  waitingForMedia$.pipe(scope.bind()).subscribe((waiting) => {
-    logger.info(`[RemoteUserMedia ${inputs.id}] waitingForMedia=${waiting}`);
-  });
-
   return {
     ...baseUserMedia,
     ...createVolumeControls(scope, {
@@ -83,6 +68,15 @@ export function createRemoteUserMedia(
         ),
       ),
     ),
-    waitingForMedia$,
+    waitingForMedia$: scope.behavior(
+      combineLatest(
+        [inputs.livekitRoom$, inputs.participant$],
+        (livekitRoom, participant) =>
+          // If livekitRoom is undefined, the user is not attempting to publish on
+          // any transport and so we shouldn't expect a participant. (They might
+          // be a subscribe-only bot for example.)
+          livekitRoom !== undefined && participant === null,
+      ),
+    ),
   };
 }

src/utils/errors.ts

@@ -7,6 +7,7 @@ Please see LICENSE in the repository root for full details.
 
 import { t } from "i18next";
 import { type ConnectionError } from "livekit-client";
+import { HTTPError, MatrixError } from "matrix-js-sdk";
 
 import { i18nKey } from "./i18n";
 
@@ -95,12 +96,20 @@ export class MatrixRTCTransportMissingError extends ElementCallError {
  * Error indicating that the connection to the call was lost and could not be re-established.
  */
 export class ConnectionLostError extends ElementCallError {
-  public constructor() {
+  /**
+   * Creates an instance of ConnectionLostError.
+   *
+   * @param cause - The underlying error that made us give up on the
+   * connection, if there is one. It is not shown to the user directly, but it
+   * ends up in the technical details of the error screen and in Sentry.
+   */
+  public constructor(cause?: Error) {
     super(
       t("error.connection_lost"),
       ErrorCode.CONNECTION_LOST_ERROR,
       ErrorCategory.NETWORK_CONNECTIVITY,
       t("error.connection_lost_description"),
+      cause,
     );
   }
 }
@@ -293,3 +302,76 @@ export class LivekitConnectionError extends ElementCallError {
     this.localisedMessageValues = { reason: cause.reasonName };
   }
 }
+
+/** Maximum number of `cause` levels walked by {@link describeErrorChain}. */
+const MAX_CAUSE_DEPTH = 8;
+
+/** Prefix that `@sentry/react` gives the synthetic error it appends as a cause. */
+const SENTRY_WRAPPER_NAME = "React ErrorBoundary ";
+
+/**
+ * Describes a single error, including the protocol level details that Matrix
+ * and HTTP errors carry but leave out of their `message`.
+ */
+function describeError(error: unknown): string {
+  if (error instanceof MatrixError) {
+    // An `M_UNKNOWN` errcode usually means the failure did not come from the
+    // homeserver at all: when we run as a widget, the hosting client's widget
+    // driver serialises any error it cannot map onto a Matrix error that way
+    // (see `MatrixError.asWidgetApiErrorData`). The url and status are then far
+    // more telling than the errcode, so always print them.
+    const parts = [
+      `errcode=${error.errcode ?? "<none>"}`,
+      `httpStatus=${error.httpStatus ?? "<none>"}`,
+    ];
+    if (error.url) parts.push(`url=${error.url}`);
+    if (error.error) parts.push(`error=${error.error}`);
+    return `MatrixError(${parts.join(", ")}): ${error.message}`;
+  }
+  if (error instanceof HTTPError)
+    return `HTTPError(httpStatus=${error.httpStatus ?? "<none>"}): ${error.message}`;
+  if (error instanceof ElementCallError)
+    return `ElementCallError(code=${error.code}, category=${error.category}): ${error.localisedTitle}`;
+  if (error instanceof Error) return `${error.name}: ${error.message}`;
+  return `Non-error value: ${String(error)}`;
+}
+
+/**
+ * Renders an error together with its whole `cause` chain.
+ *
+ * By the time an error reaches the error screen it has usually been wrapped
+ * several times over (the MembershipManager scheduler, an
+ * {@link ElementCallError} subclass, a context wrapper at the call site, ...),
+ * so showing only the outermost error, or a single `cause` hop, tends to hide
+ * the request that actually failed.
+ *
+ * @param error - The error to describe.
+ * @returns One entry per error in the chain, outermost wrapper first. A chain
+ * of length one means we have nothing beyond the error itself to report.
+ */
+export function describeErrorChain(error: unknown): string[] {
+  const lines: string[] = [];
+  let current: unknown = error;
+  for (
+    let depth = 0;
+    current !== undefined && depth < MAX_CAUSE_DEPTH;
+    depth++
+  ) {
+    // `@sentry/react` appends a synthetic error to the end of the chain to
+    // carry the React component stack. That is useful in Sentry, but here it
+    // only repeats the message of the error it is attached to.
+    if (
+      current instanceof Error &&
+      current.name.startsWith(SENTRY_WRAPPER_NAME)
+    )
+      break;
+    lines.push(
+      (depth === 0 ? "" : `${"  ".repeat(depth)}caused by: `) +
+        describeError(current),
+    );
+    // Only `Error`s carry a `cause`, and a self-referencing one would loop.
+    if (!(current instanceof Error) || current.cause === current) break;
+    current = current.cause;
+  }
+  return lines;
+}