In the starred messages view, new starred message events crash the app

[PIG208]

To reproduce:

1. Go to the starred messages view on the mobile app
2. Log into the same account on another device
3. Star an old message

I haven't yet diagnosed the cause of the crash, but looking at the error message, it is likely that the client relies on the assumption that a starred message is known to the app. This is not the case when that message is ancient and hasn't been fetched before.

Error Details

Error: getFetchedMessagesForNarrow: message with id is missing in getMessages(state)
The error may be correlated with this previous error:
index.android.bundle:1881:1699
map@[native code]
index.android.bundle:1881:1544
C@index.android.bundle:1158:886
index.android.bundle:1157:1038
C@index.android.bundle:1158:886
index.android.bundle:1157:1004
C@index.android.bundle:1158:886
index.android.bundle:1157:1004
C@index.android.bundle:1158:886
index.android.bundle:2469:4330
t@index.android.bundle:1153:1076
f@index.android.bundle:1122:149
index.android.bundle:1122:347
notify@index.android.bundle:1122:309
notifyNestedSubs@index.android.bundle:1122:724
notifyNestedSubs@[native code]
C@index.android.bundle:1126:3030
f@index.android.bundle:1122:149
index.android.bundle:1122:347
_e@index.android.bundle:81:93155
xe@index.android.bundle:81:12945
notify@index.android.bundle:1122:309
notifyNestedSubs@index.android.bundle:1122:724
f@index.android.bundle:1122:149
E@index.android.bundle:2692:1608
index.android.bundle:2638:366
h@index.android.bundle:2013:4962
index.android.bundle:2013:6131
s@index.android.bundle:107:746
index.android.bundle:107:2101
s@index.android.bundle:107:746
e@index.android.bundle:107:1233
index.android.bundle:107:1389
index.android.bundle:101:618
index.android.bundle:101:645
index.android.bundle:110:1748
T@index.android.bundle:110:496
k@index.android.bundle:110:886
callReactNativeMicrotasks@index.android.bundle:110:3148
value@index.android.bundle:61:2874
index.android.bundle:61:965
value@index.android.bundle:61:2510
value@index.android.bundle:61:923
value@[native code]
value@[native code]



Component Stack:

    in Unknown
    in Unknown
    in Connect(Component)
    in Unknown
    in Unknown
    in Unknown
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in Unknown
    in RCTView
    in Unknown
    in u
    in Unknown
    in PanGestureHandler
    in Unknown
    in RCTView
    in Unknown
    in u
    in Unknown
    in RCTView
    in Unknown
    in o
    in Unknown
    in RNSScreen
    in u
    in Unknown
    in n
    in Suspense
    in Unknown
    in _
    in r
    in a
    in Unknown
    in RNSScreenContainer
    in ScreenContainer
    in Unknown
    in n
    in o
    in Unknown
    in RNGestureHandlerRootView
    in Unknown
    in s
    in Unknown
    in Unknown
    in Unknown
    in Unknown
    in Unknown
    in Unknown
    in Unknown
    in RCTView
    in Unknown
    in RCTView
    in UnknownError: getFetchedMessagesForNarrow: message with id is missing in getMessages(state)
The error may be correlated with this previous error:
index.android.bundle:1881:1699
map@[native code]
index.android.bundle:1881:1544
C@index.android.bundle:1158:886
index.android.bundle:1157:1038
C@index.android.bundle:1158:886
index.android.bundle:1157:1004
C@index.android.bundle:1158:886
index.android.bundle:1157:1004
C@index.android.bundle:1158:886
index.android.bundle:2469:4330
t@index.android.bundle:1153:1076
f@index.android.bundle:1122:149
index.android.bundle:1122:347
notify@index.android.bundle:1122:309
notifyNestedSubs@index.android.bundle:1122:724
notifyNestedSubs@[native code]
C@index.android.bundle:1126:3030
f@index.android.bundle:1122:149
index.android.bundle:1122:347
_e@index.android.bundle:81:93155
xe@index.android.bundle:81:12945
notify@index.android.bundle:1122:309
notifyNestedSubs@index.android.bundle:1122:724
f@index.android.bundle:1122:149
E@index.android.bundle:2692:1608
index.android.bundle:2638:366
h@index.android.bundle:2013:4962
index.android.bundle:2013:6131
s@index.android.bundle:107:746
index.android.bundle:107:2101
s@index.android.bundle:107:746
e@index.android.bundle:107:1233
index.android.bundle:107:1389
index.android.bundle:101:618
index.android.bundle:101:645
index.android.bundle:110:1748
T@index.android.bundle:110:496
k@index.android.bundle:110:886
callReactNativeMicrotasks@index.android.bundle:110:3148
value@index.android.bundle:61:2874
index.android.bundle:61:965
value@index.android.bundle:61:2510
value@index.android.bundle:61:923
value@[native code]
value@[native code]



Component Stack:

    in Unknown
    in Unknown
    in Connect(Component)
    in Unknown
    in Unknown
    in Unknown
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in Unknown
    in RCTView
    in Unknown
    in u
    in Unknown
    in PanGestureHandler
    in Unknown
    in RCTView
    in Unknown
    in u
    in Unknown
    in RCTView
    in Unknown
    in o
    in Unknown
    in RNSScreen
    in u
    in Unknown
    in n
    in Suspense
    in Unknown
    in _
    in r
    in a
    in Unknown
    in RNSScreenContainer
    in ScreenContainer
    in Unknown
    in n
    in o
    in Unknown
    in RNGestureHandlerRootView
    in Unknown
    in s
    in Unknown
    in Unknown
    in Unknown
    in Unknown
    in Unknown
    in Unknown
    in Unknown
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in u
    in c
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in Unknown
    in Unknown
    in l
    in IntlProvider
    in Unknown
    in RCTView
    in Unknown
    in r
    in Connect(r)
    in Unknown
    in RNCSafeAreaProvider
    in Unknown
    in Unknown
    in n
    in Unknown
    in r
    in r
    in Unknown
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in n

Call Stack:

index.android.bundle:1881:1699
map@[native code]
index.android.bundle:1881:1544
C@index.android.bundle:1158:886
index.android.bundle:1157:1038
C@index.android.bundle:1158:886
index.android.bundle:1157:1004
C@index.android.bundle:1158:886
index.android.bundle:1157:1004
C@index.android.bundle:1158:886
index.android.bundle:2469:4330
index.android.bundle:1153:645
index.android.bundle:1153:1249
index.android.bundle:1117:530
S@index.android.bundle:2469:4271
index.android.bundle:2469:488
hr@index.android.bundle:81:41156
nl@index.android.bundle:81:52479
Ea@index.android.bundle:81:78041
Pa@index.android.bundle:81:77943
xa@index.android.bundle:81:77708
Sa@index.android.bundle:81:74696
Sa@[native code]
ut@index.android.bundle:81:25302
_e@index.android.bundle:81:93216
xe@index.android.bundle:81:12945
notify@index.android.bundle:1122:309
notifyNestedSubs@index.android.bundle:1122:724
f@index.android.bundle:1122:149
E@index.android.bundle:2692:1608
index.android.bundle:2638:366
h@index.android.bundle:2013:4962
index.android.bundle:2013:6131
s@index.android.bundle:107:746
index.android.bundle:107:2101
s@index.android.bundle:107:746
e@index.android.bundle:107:1233
index.android.bundle:107:1389
index.android.bundle:101:618
index.android.bundle:101:645
index.android.bundle:110:1748
T@index.android.bundle:110:496
k@index.android.bundle:110:886
callReactNativeMicrotasks@index.android.bundle:110:3148
value@index.android.bundle:61:2874
index.android.bundle:61:965
value@index.android.bundle:61:2510
value@index.android.bundle:61:923
value@[native code]
value@[native code]
    in u
    in c
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in Unknown
    in Unknown
    in l
    in IntlProvider
    in Unknown
    in RCTView
    in Unknown
    in r
    in Connect(r)
    in Unknown
    in RNCSafeAreaProvider
    in Unknown
    in Unknown
    in n
    in Unknown
    in r
    in r
    in Unknown
    in RCTView
    in Unknown
    in RCTView
    in Unknown
    in n

Call Stack:

index.android.bundle:1881:1699
map@[native code]
index.android.bundle:1881:1544
C@index.android.bundle:1158:886
index.android.bundle:1157:1038
C@index.android.bundle:1158:886
index.android.bundle:1157:1004
C@index.android.bundle:1158:886
index.android.bundle:1157:1004
C@index.android.bundle:1158:886
index.android.bundle:2469:4330
index.android.bundle:1153:645
index.android.bundle:1153:1249
index.android.bundle:1117:530
S@index.android.bundle:2469:4271
index.android.bundle:2469:488
hr@index.android.bundle:81:41156
nl@index.android.bundle:81:52479
Ea@index.android.bundle:81:78041
Pa@index.android.bundle:81:77943
xa@index.android.bundle:81:77708
Sa@index.android.bundle:81:74696
Sa@[native code]
ut@index.android.bundle:81:25302
_e@index.android.bundle:81:93216
xe@index.android.bundle:81:12945
notify@index.android.bundle:1122:309
notifyNestedSubs@index.android.bundle:1122:724
f@index.android.bundle:1122:149
E@index.android.bundle:2692:1608
index.android.bundle:2638:366
h@index.android.bundle:2013:4962
index.android.bundle:2013:6131
s@index.android.bundle:107:746
index.android.bundle:107:2101
s@index.android.bundle:107:746
e@index.android.bundle:107:1233
index.android.bundle:107:1389
index.android.bundle:101:618
index.android.bundle:101:645
index.android.bundle:110:1748
T@index.android.bundle:110:496
k@index.android.bundle:110:886
callReactNativeMicrotasks@index.android.bundle:110:3148
value@index.android.bundle:61:2874
index.android.bundle:61:965
value@index.android.bundle:61:2510
value@index.android.bundle:61:923
value@[native code]
value@[native code]

[gnprice]

Thanks for the report.

Looking at the code around the error, it's thrown because we've breached the invariant that state.narrows contains only message IDs that appear in state.messages.

And looking at narrowsReducer.js which maintains state.narrows, I see the bug there: it's that when we receive an event saying a message was starred, we add it unconditionally to the state.narrows entry for the starred-messages narrow (if we have such an entry), without checking if the message appears in state.messages.

It looks like the same issue also applies to events saying a message gained a mention flag.

It'd be possible to fix this bug. But I think this situation is rare, which is consistent with the fact that we haven't heard a report of it before. Given that and that this app is in maintenance mode, I think we won't fix it in this codebase and will instead indirectly fix it by finishing and launching the new zulip-flutter app.

[gnprice]

Meanwhile, taking this as an opportunity to avoid a similar bug in zulip-flutter:

The zulip-flutter analogue of state.narrows is MessageListView, the view-model for a message list. It doesn't currently respond to UpdateMessageFlagsEvent, so this doesn't arise. When we add that functionality, the most obvious thing will be to handle it the same way we handle messages getting moved into a channel or topic narrow, which is already conservative about preventing this sort of issue:

  void _messagesMovedIntoNarrow() {
    // If there are some messages we don't have in [MessageStore], and they
    // occur later than the messages we have here, then we just have to
    // re-fetch from scratch.  That's always valid, so just do that always.
    // TODO in cases where we do have data to do better, do better.
    _reset();
    notifyListeners();
    fetchInitial();
  }

I'll also make a note in the relevant issue, to make sure we watch for this potential bug. (… Actually it looks like we didn't quite have such an issue in the tracker; just filed zulip/zulip-flutter#1006 for it.)

[mayankdhangar2408]

hey @gnprice @PIG208 is this issue still unsolved, if it is unsolved then assign it to me and provide some links for description

[gnprice]

@mayankdhangar2408 See my reply to another of your comments: #5885 (comment)