api: Add ReactionOp.unknown

Author: sm-sayedi

lib/api/model/events.dart

@@ -1727,6 +1727,7 @@ class ReactionEvent extends Event {
   @JsonKey(includeToJson: true)
   String get type => 'reaction';
 
+  @JsonKey(unknownEnumValue: ReactionOp.unknown)
   final ReactionOp op;
 
   final String emojiName;
@@ -1758,6 +1759,9 @@ class ReactionEvent extends Event {
 enum ReactionOp {
   add,
   remove,
+
+  /// A new, unrecognized operation.
+  unknown;
 }
 
 /// A Zulip event of type `heartbeat`: https://zulip.com/api/get-events#heartbeat

lib/api/model/events.g.dart

@@ -832,6 +832,8 @@ class MessageStoreImpl extends HasChannelStore with MessageStore, _OutboxMessage
   }
 
   void handleReactionEvent(ReactionEvent event) {
+    if (event.op == .unknown) return;
+
     final message = messages[event.messageId];
     if (message == null) return;
 
@@ -852,6 +854,8 @@ class MessageStoreImpl extends HasChannelStore with MessageStore, _OutboxMessage
           emojiCode: event.emojiCode,
           userId: event.userId,
         );
+      case .unknown:
+        // Shouldn't reach here because of the early return.
     }
     _notifyMessageListViewsForOneMessage(event.messageId);
   }

lib/model/message.dart

@@ -93,6 +93,10 @@ extension TypingEventChecks on Subject<TypingEvent> {
   Subject<TopicName?> get topic => has((e) => e.topic, 'topic');
 }
 
+extension ReactionEventChecks on Subject<ReactionEvent> {
+  Subject<ReactionOp> get op => has((e) => e.op, 'op');
+}
+
 extension HeartbeatEventChecks on Subject<HeartbeatEvent> {
   // No properties not covered by Event.
 }

test/api/model/events_checks.dart

@@ -423,4 +423,25 @@ void main() {
       })).recipientIds.isNotNull().deepEquals([1, 2, 4, 8, 10]);
     });
   });
+
+  group('reaction event', () {
+    final json = Map<String, dynamic>.unmodifiable({
+      'id': 1,
+      'type': 'reaction',
+      'op': 'add',
+      'emoji_name': '+1',
+      'emoji_code': '1f44d',
+      'reaction_type': 'unicode_emoji',
+      'user_id': 100,
+      'message_id': 1000,
+    });
+
+    test('handle unknown op', () {
+      check(ReactionEvent.fromJson(json)).op.equals(.add);
+
+      for (final unknown in ['unknown_op', '']) {
+        check(ReactionEvent.fromJson({...json, 'op': unknown})).op.equals(.unknown);
+      }
+    });
+  });
 }