fix(calls): the call bar shows "Call disconnected" and reconnects when sync is back (#318)

After a homeserver stall Element Call showed "Connection lost" while the
call bar still looked joined. Handle the fork's io.lotus.call_error:
show "Call disconnected" with a Reconnect button (io.lotus.reconnect),
and reconnect automatically once sync is back.

Fixes #318

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/components/CallEmbedProvider.tsx

@@ -86,6 +86,7 @@ import { CallAvatarAnimation } from '../styles/Animations.css';
 import { webRTCSupported } from '../utils/rtc';
 import { CallsUnavailableMessage } from '../features/call/CallsUnavailable';
 import { zIndices } from '../styles/zIndex';
+import { useReconnectWhenSynced } from '../hooks/useCallError';
 
 const PIP_MIN_W = 200;
 const PIP_MIN_H = 112;
@@ -793,6 +794,7 @@ function CallUtils({ embed, joined }: { embed: CallEmbed; joined: boolean }) {
   useCallPolicyRevokedToast(embed, joined);
   useCallEndedToast(embed);
   useScreenshareNotices(embed);
+  useReconnectWhenSynced(embed.control);
   // [Gitea #43] The in-frame screenshare button follows the same room policy
   // as the host bar's (hidden where the server would refuse the share).
   const { allowScreenshare } = useRoomCallPolicy(embed.room);

src/app/features/call-status/CallStatus.tsx

@@ -1,5 +1,5 @@
 import React, { useMemo } from 'react';
-import { Box, Spinner, Text, color } from 'folds';
+import { Box, Button, Spinner, Text, color } from 'folds';
 import { useAtomValue } from 'jotai';
 import classNames from 'classnames';
 import { LiveChip } from './LiveChip';
@@ -18,6 +18,7 @@ import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { MemberSpeaking } from './MemberSpeaking';
 import { clockSkewAtom } from '../../state/clockSkew';
 import { describeSkewVsServer } from '../../utils/clockSkew';
+import { useCallError } from '../../hooks/useCallError';
 
 type CallStatusProps = {
   callEmbed: CallEmbed;
@@ -42,6 +43,8 @@ export function CallStatus({ callEmbed }: CallStatusProps) {
   const clockSkew = useAtomValue(clockSkewAtom);
 
   const compact = screenSize === ScreenSize.Mobile;
+  // [Gitea #318] The call dropped ("Connection lost" in the frame).
+  const callError = useCallError(callEmbed.control);
 
   const memberVisible = callJoined && callMembers.length > 0;
 
@@ -65,6 +68,25 @@ export function CallStatus({ callEmbed }: CallStatusProps) {
           {!compact && (
             <>
               <CallRoomName room={room} />
+              {callError && (
+                <>
+                  <StatusDivider />
+                  <Text size="T200" truncate role="alert" style={{ color: color.Critical.Main }}>
+                    Call disconnected
+                  </Text>
+                  {callError.recoverable && (
+                    <Button
+                      size="300"
+                      radii="300"
+                      variant="Critical"
+                      fill="Soft"
+                      onClick={() => callEmbed.control.reconnect()}
+                    >
+                      <Text size="B300">Reconnect</Text>
+                    </Button>
+                  )}
+                </>
+              )}
               {clockSkew.warning && clockSkew.skewMs !== null && (
                 <>
                   <StatusDivider />
@@ -102,8 +124,19 @@ export function CallStatus({ callEmbed }: CallStatusProps) {
       {memberVisible && !compact && <StatusDivider />}
       <Box shrink="No" alignItems="Center" gap="Inherit">
         {compact && (
-          <Box grow="Yes">
+          <Box grow="Yes" alignItems="Center" gap="200">
             <CallRoomName room={room} />
+            {callError?.recoverable && (
+              <Button
+                size="300"
+                radii="300"
+                variant="Critical"
+                fill="Soft"
+                onClick={() => callEmbed.control.reconnect()}
+              >
+                <Text size="B300">Reconnect</Text>
+              </Button>
+            )}
           </Box>
         )}
         <CallControl callJoined={callJoined} compact={compact} callEmbed={callEmbed} />

src/app/hooks/useCallError.ts

@@ -0,0 +1,41 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
+import { SyncState } from 'matrix-js-sdk';
+import { CALL_ERROR_CHANGED, CallControl } from '../plugins/call/CallControl';
+import { CallErrorState } from '../plugins/call/callError';
+import { useMatrixClient } from './useMatrixClient';
+import { useSyncState } from './useSyncState';
+
+/** [Gitea #318] The fork's current call error (null while the call is fine). */
+export function useCallError(control: CallControl): CallErrorState {
+  const [err, setErr] = useState(control.callError);
+  useEffect(() => {
+    const on = () => setErr(control.callError);
+    on();
+    control.on(CALL_ERROR_CHANGED, on);
+    return () => {
+      control.off(CALL_ERROR_CHANGED, on);
+    };
+  }, [control]);
+  return err;
+}
+
+/**
+ * [Gitea #318] After a homeserver stall the call drops with "Connection
+ * lost". Once sync is back, reconnect automatically (once per drop).
+ */
+export function useReconnectWhenSynced(control: CallControl): void {
+  const mx = useMatrixClient();
+  const err = useCallError(control);
+  const tried = useRef<CallErrorState>(null);
+  useSyncState(
+    mx,
+    useCallback(
+      (state: SyncState | null) => {
+        if (state !== SyncState.Syncing || !err?.recoverable || tried.current === err) return;
+        tried.current = err;
+        control.reconnect();
+      },
+      [err, control],
+    ),
+  );
+}

src/app/plugins/call/CallControl.ts

@@ -3,6 +3,7 @@ import { EventEmitter } from 'events';
 import { CallControlState } from './CallControlState';
 import { ElementMediaStateDetail, ElementMediaStatePayload, ElementWidgetActions } from './types';
 import { canDelegateCapability } from './utils';
+import { CallErrorState, parseCallError } from './callError';
 
 export enum CallControlEvent {
   StateUpdate = 'state_update',
@@ -54,6 +55,8 @@ export function parseForkHotkeyReport(data: unknown): ForkHotkeyReport | null {
   };
 }
 
+export const CALL_ERROR_CHANGED = 'call_error_changed';
+
 export class CallControl extends EventEmitter implements CallControlState {
   private state: CallControlState;
 
@@ -205,6 +208,27 @@ export class CallControl extends EventEmitter implements CallControlState {
     return this._audioOutputId;
   }
 
+  // [Gitea #318] The fork's error page ("Connection lost") is up; the host
+  // kept showing the call as joined with controls that did nothing.
+  private _callError: CallErrorState = null;
+
+  public get callError(): CallErrorState {
+    return this._callError;
+  }
+
+  /** The fork's `io.lotus.call_error` report. */
+  public onCallError(data: unknown) {
+    const next = parseCallError(data);
+    if (next === undefined) return;
+    this._callError = next;
+    this.emit(CALL_ERROR_CHANGED);
+  }
+
+  /** Press the fork's Reconnect / Try again. */
+  public reconnect(): void {
+    this.call.transport.send('io.lotus.reconnect', {}).catch(() => undefined);
+  }
+
   public setAudioOutput(deviceId: string): void {
     this._audioOutputId = deviceId;
     this.sendAudioOutput(deviceId);

src/app/plugins/call/CallEmbed.ts

@@ -450,6 +450,12 @@ export class CallEmbed {
         this.control.onControlsState((evt.detail as { data?: unknown } | undefined)?.data);
       }),
     );
+    // [Gitea #318] The fork's error page ("Connection lost") is up / cleared.
+    this.disposables.push(
+      this.listenAction('io.lotus.call_error', (evt) => {
+        this.control.onCallError((evt.detail as { data?: unknown } | undefined)?.data);
+      }),
+    );
     // [Gitea #43] PTT / deafen keys pressed while focus is inside the frame.
     this.disposables.push(
       this.listenAction('io.lotus.hotkey', (evt) => {

src/app/plugins/call/callError.test.ts

@@ -0,0 +1,17 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { parseCallError } from './callError';
+
+test('parseCallError (#318)', () => {
+  assert.deepEqual(parseCallError({ code: 'CONNECTION_LOST_ERROR', recoverable: true }), {
+    code: 'CONNECTION_LOST_ERROR',
+    recoverable: true,
+  });
+  assert.deepEqual(parseCallError({ code: 'E2EE_NOT_SUPPORTED' }), {
+    code: 'E2EE_NOT_SUPPORTED',
+    recoverable: false,
+  });
+  assert.equal(parseCallError({ code: null }), null);
+  assert.equal(parseCallError({}), undefined);
+  assert.equal(parseCallError('x'), undefined);
+});

src/app/plugins/call/callError.ts

@@ -0,0 +1,14 @@
+/**
+ * [Gitea #318] The fork's `io.lotus.call_error`: its error page is showing
+ * (`{ code, recoverable }`) or was cleared (`{ code: null }`).
+ */
+export type CallErrorState = { code: string; recoverable: boolean } | null;
+
+/** Pure: parse a report; undefined for garbage (ignored). */
+export function parseCallError(data: unknown): CallErrorState | undefined {
+  if (typeof data !== 'object' || data === null) return undefined;
+  const { code, recoverable } = data as { code?: unknown; recoverable?: unknown };
+  if (code === null) return null;
+  if (typeof code !== 'string' || !code) return undefined;
+  return { code, recoverable: recoverable === true };
+}