typing_status: Do not allow adding self as typist.

The server usually does not send events notifying the user themself
typing. But having this check gives us a stronger guarantee that the
maps do not contain the self user.

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

lib/api/model/events.dart

@@ -901,7 +901,7 @@ class TypingEvent extends Event {
     required this.recipientIds,
     required this.streamId,
     required this.topic,
-  }) : assert(isSortedWithoutDuplicates(recipientIds ?? []));
+  }) : assert(recipientIds == null || isSortedWithoutDuplicates(recipientIds));
 
   static Object? _readSenderId(Map<Object?, Object?> json, String key) {
     return (json['sender'] as Map<String, dynamic>)['user_id'];

lib/model/typing_status.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:flutter/foundation.dart';
 
 import '../api/model/events.dart';
+import '../log.dart';
 import 'narrow.dart';
 
 /// The model for tracking the typing status organized by narrows.
@@ -38,6 +39,10 @@ class TypingStatus extends ChangeNotifier {
   }
 
   bool _addTypist(SendableNarrow narrow, int typistUserId) {
+    if (typistUserId == selfUserId) {
+      assert(debugLog('typing status: adding self as typist'));
+      return false;
+    }
     final narrowTimerMap = _timerMapsByNarrow[narrow] ??= {};
     final typistTimer = narrowTimerMap[typistUserId];
     final isNewTypist = typistTimer == null;

test/model/typing_status_test.dart

@@ -97,6 +97,15 @@ void main() {
       checkTypists({groupNarrow: [eg.otherUser, eg.thirdUser]});
       checkNotifiedOnce();
     });
+
+    test('ignore adding self as typist', () {
+      prepareModel();
+
+      model.handleTypingEvent(
+        eg.typingEvent(groupNarrow, TypingOp.start, eg.selfUser.userId));
+      checkTypists({});
+      checkNotNotified();
+    });
   });
 
   group('handle typing stop events', () {