On malformed event and /register response, show stack trace to user

lib/model/store.dart

@@ -1175,7 +1175,7 @@ class UpdateMachine {
       InitialSnapshot? result;
       try {
         result = await registerQueue(connection);
-      } catch (e, s) {
+      } catch (e, stackTrace) {
         stopAndThrowIfNoAccount();
         // TODO(#890): tell user if initial-fetch errors persist, or look non-transient
         final ZulipVersionData? zulipVersionData;
@@ -1192,7 +1192,20 @@ class UpdateMachine {
             assert(debugLog('Error fetching initial snapshot: $e'));
             // Print stack trace in its own log entry; log entries are truncated
             // at 1 kiB (at least on Android), and stack can be longer than that.
-            assert(debugLog('Stack:\n$s'));
+            assert(debugLog('Stack:\n$stackTrace'));
+            if (e case NetworkException(cause: SocketException())) {
+              // A [SocketException] is common when the device is asleep.
+            } else {
+              // TODO: When the error seems transient, do keep retrying but
+              //   don't spam this feedback.
+              // TODO(#1948) Break the retry loop on non-transient errors.
+              _reportConnectionErrorToUserAndPromiseRetry(e,
+                realmUrl: connection.realmUrl,
+                // The stack trace is mostly useful for
+                // `MalformedServerResponseException`s, and will be noise for
+                // routine exceptions like from network problems.
+                stackTrace: e is ApiRequestException ? null : stackTrace);
+            }
         }
         assert(debugLog('Backing off, then will retry…'));
         await (backoffMachine ??= BackoffMachine()).wait();
@@ -1339,9 +1352,9 @@ class UpdateMachine {
           lastEventId = events.last.id;
         }
       }
-    } catch (e) {
+    } catch (e, stackTrace) {
       if (_disposed) return;
-      await _handlePollError(e);
+      await _handlePollError(e, stackTrace);
       assert(_disposed);
       return;
     }
@@ -1458,7 +1471,7 @@ class UpdateMachine {
   /// See also:
   ///  * [_handlePollRequestError], which handles certain errors
   ///    and causes them not to reach this method.
-  Future<void> _handlePollError(Object error) async {
+  Future<void> _handlePollError(Object error, StackTrace stackTrace) async {
     // An error occurred, other than the transient request errors we retry on.
     // This means either a lost/expired event queue on the server (which is
     // normal after the app is offline for a period like 10 minutes),
@@ -1493,9 +1506,14 @@ class UpdateMachine {
         isUnexpected = true;
 
       default:
-        assert(debugLog('BUG: Unexpected error in event polling: $error\n' // TODO(log)
-          'Replacing event queue…'));
-        _reportToUserErrorConnectingToServer(error);
+        assert(debugLog('BUG: Unexpected error in event polling: $error')); // TODO(log)
+        // Print stack trace in its own log entry; log entries are truncated
+        // at 1 kiB (at least on Android), and stack can be longer than that.
+        assert(debugLog('Stack trace:\n$stackTrace'));
+        assert(debugLog('Replacing event queue…'));
+        _reportConnectionErrorToUserAndPromiseRetry(error,
+          realmUrl: store.realmUrl,
+          stackTrace: stackTrace);
         // Similar story to the _EventHandlingException case;
         // separate only so that that other case can print more context.
         // The bug here could be in the server if it's an ApiRequestException,
@@ -1526,16 +1544,28 @@ class UpdateMachine {
   void _maybeReportToUserTransientError(Object error) {
     _accumulatedTransientFailureCount++;
     if (_accumulatedTransientFailureCount > transientFailureCountNotifyThreshold) {
-      _reportToUserErrorConnectingToServer(error);
+      _reportConnectionErrorToUserAndPromiseRetry(error, realmUrl: store.realmUrl);
     }
   }
 
-  void _reportToUserErrorConnectingToServer(Object error) {
+  /// Give brief UI feedback that we failed to connect to the server
+  /// and that we'll try again.
+  static void _reportConnectionErrorToUserAndPromiseRetry(
+    Object error, {
+    StackTrace? stackTrace,
+    required Uri realmUrl,
+  }) {
     final zulipLocalizations = GlobalLocalizations.zulipLocalizations;
+
+    final details = StringBuffer()..write(error.toString());
+    if (stackTrace != null) {
+      details.write('\nStack:\n$stackTrace');
+    }
+
     reportErrorToUserBriefly(
       zulipLocalizations.errorConnectingToServerShort,
       details: zulipLocalizations.errorConnectingToServerDetails(
-        store.realmUrl.toString(), error.toString()));
+        realmUrl.toString(), details.toString()));
   }
 
   /// Cleans up resources and tells the instance not to make new API requests.

lib/widgets/dialog.dart

@@ -63,7 +63,14 @@ Widget? _adaptiveContent(Widget? content) {
     case TargetPlatform.macOS:
       // A [SingleChildScrollView] (wrapping both title and content) is already
       // created by [CupertinoAlertDialog].
-      return content;
+      return DefaultTextStyle.merge(
+        // The "alert description" is start-aligned in one example in Apple's
+        // HIG document:
+        //   https://developer.apple.com/design/human-interface-guidelines/alerts#Anatomy
+        // (Confusingly, in 2025-10, it's center-aligned in the graphic at the
+        // *top* of that page; shrug.)
+        textAlign: TextAlign.start,
+        child: content);
   }
 }