msglist: In unsubscribed channel, clear edit progress on request success

This fixes the rest of the "third buggy behavior" described
in zulip#1798: it fixes it for the edit-message case.

Fixes-partly: zulip#1798

Author: chrisbobbe

lib/model/message.dart

@@ -519,7 +519,8 @@ class MessageStoreImpl extends HasChannelStore with MessageStore, _OutboxMessage
         content: newContent,
         prevContentSha256: sha256.convert(utf8.encode(originalRawContent)).toString());
       // On success, we'll clear the status from _editMessageRequests
-      // when we get the event.
+      // when we get the event (or below, if in an unsubscribed channel).
+      if (_disposed) return;
     } catch (e) {
       // TODO(log) if e is something unexpected
 
@@ -536,6 +537,15 @@ class MessageStoreImpl extends HasChannelStore with MessageStore, _OutboxMessage
       _notifyMessageListViewsForOneMessage(messageId);
       rethrow;
     }
+
+    final message = messages[messageId];
+    if (message is StreamMessage && subscriptions[message.streamId] == null) {
+      // The message is in an unsubscribed channel. We don't expect an event
+      // (see "third buggy behavior" in #1798) but we know the edit request
+      // succeeded, so, clear the pending-edit state.
+      _editMessageRequests.remove(messageId);
+      _notifyMessageListViewsForOneMessage(messageId);
+    }
   }
 
   @override

test/model/message_test.dart

@@ -1053,6 +1053,30 @@ void main() {
       check(store.getEditMessageErrorStatus(message.id)).isNull();
       checkNotNotified();
     }));
+
+    test('request succeeds, in unsubscribed channel', () => awaitFakeAsync((async) async {
+      final channel = eg.stream();
+      message = eg.streamMessage(stream: channel, sender: eg.selfUser);
+      await prepare(
+        narrow: ChannelNarrow(channel.streamId),
+        stream: channel,
+        isChannelSubscribed: false,
+      );
+      await prepareMessages([message]);
+      check(connection.takeRequests()).length.equals(1); // message-list fetchInitial
+
+      connection.prepare(
+        json: UpdateMessageResult().toJson(), delay: Duration(seconds: 1));
+      unawaited(store.editMessage(messageId: message.id,
+        originalRawContent: 'old content', newContent: 'new content'));
+      checkRequest(message.id, prevContent: 'old content', content: 'new content');
+      checkNotifiedOnce();
+
+      async.elapse(Duration(seconds: 1));
+      // Outbox status cleared already (we don't expect an edit-message event).
+      check(store.getEditMessageErrorStatus(message.id)).isNull();
+      checkNotifiedOnce();
+    }));
   });
 
   group('selfCanDeleteMessage', () {

test/widgets/compose_box_test.dart

@@ -2107,6 +2107,21 @@ void main() {
       checkContentInputValue(tester, expectedContentText);
     }
 
+    /// Check whether the message in the message list says "SAVING EDIT…".
+    ///
+    /// This state is tested more thoroughly
+    /// in test/widgets/message_list_test.dart, naturally.
+    void checkEditInProgressInMsglist(WidgetTester tester,
+        {required int messageId, required bool expected}) {
+      final messageFinder = find.byWidgetPredicate((widget) =>
+        widget is MessageWithPossibleSender && widget.item.message.id == messageId);
+
+      check(find.descendant(
+        of: messageFinder,
+        matching: find.text('SAVING EDIT…'),
+      ).evaluate().length).equals(expected ? 1 : 0);
+    }
+
     void testSmoke({required Narrow narrow, required _EditInteractionStart start}) {
       testWidgets('smoke: $narrow, ${start.message()}', (tester) async {
         await prepareEditMessage(tester, narrow: narrow);
@@ -2157,6 +2172,10 @@ void main() {
           prevContent: 'foo', content: 'some new content[file.jpg](/path/file.jpg)');
         await tester.pump(Duration.zero);
         checkNotInEditingMode(tester, narrow: narrow);
+
+        // We'll say "SAVING EDIT…" in the message list until the event arrives.
+        // (No need to make the event arrive here; message-list tests do that.)
+        checkEditInProgressInMsglist(tester, messageId: messageId, expected: true);
       });
     }
     testSmoke(narrow: channelNarrow, start: _EditInteractionStart.actionSheet);
@@ -2461,9 +2480,9 @@ void main() {
         of: find.byType(MessageWithPossibleSender),
         matching: find.text(ContentExample.emojiUnicode.expectedText!))
       ).findsOne();
-      // TODO(#1798) The message actually appears in the "SAVING EDIT…" state
-      //   (the "third buggy behavior" in #1798). We'll fix that soon,
-      //   and it'll be convenient to test that here too.
+      // Regression coverage for the "third buggy behavior"
+      // in https://github.com/zulip/zulip-flutter/issues/1798 .
+      checkEditInProgressInMsglist(tester, messageId: message.id, expected: false);
     });
   });
 }