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DragGestureRecognizer.acceptGesture null check operator used on a null value #112403

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#121615
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DragGestureRecognizer.acceptGesture null check operator used on a null value#112403
#121615
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tarobins
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P2Important issues not at the top of the work listc: crashStack traces logged to the consolecustomer: dream (g3)f: gesturesflutter/packages/flutter/gestures repository.frameworkflutter/packages/flutter repository. See also f: labels.

Description

@christopherfujino
christopherfujino
opened on Sep 26, 2022

Framework crash from internal b/249091367

UnknownError: Null check operator used on a null value
at DragGestureRecognizer.acceptGesture(monodrag.dart:334)
at GestureArenaManager._resolveByDefault(arena.dart:251)
at GestureArenaManager._tryToResolveArena.<anonymous closure>(arena.dart:232)
at _rootRun(zone.dart:1418)
at _rootRun(zone.dart:1417)
at _CustomZone.run(zone.dart:1328)
at _CustomZone.runGuarded(zone.dart:1236)
at _CustomZone.bindCallbackGuarded.<anonymous closure>(zone.dart:1276)
at _rootRun(zone.dart:1426)
at _rootRun(zone.dart:1417)
at _CustomZone.run(zone.dart:1328)
at _CustomZone.runGuarded(zone.dart:1236)
at _CustomZone.bindCallbackGuarded.<anonymous closure>(zone.dart:1276)
at _microtaskLoop(schedule_microtask.dart:40)
at _startMicrotaskLoop(schedule_microtask.dart:49)
at _startMicrotaskLoop(schedule_microtask.dart:44)

Although the line numbers are different (I'm not sure the exact framework version used in the app this stacktrace is from), I'm pretty sure it's this line: https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/gestures/monodrag.dart#L367

      final Duration timestamp = _lastPendingEventTimestamp!;

It's difficult to reason about how we got into this state, but maybe the easiest fix would be to just let _checkStart(timestamp, pointer) be a no-op when timestamp == null, WDYT @dkwingsmt?

Activity

  1. christopherfujino
    added
    frameworkflutter/packages/flutter repository. See also f: labels.
    on Sep 26, 2022
  2. dnfield
    added
    f: gesturesflutter/packages/flutter/gestures repository.
    customer: dream (g3)
    on Sep 27, 2022
  3. goderbauer
    added
    c: crashStack traces logged to the console
    P2Important issues not at the top of the work list
    on Sep 27, 2022
  4. tarobins
    self-assigned this
    on Dec 22, 2022

  5. tarobins commented on Dec 22, 2022

    @tarobins
    tarobins
    on Dec 22, 2022
    Contributor

    DragStartDetails.sourceTimeStamp can be null, so the timestamp parameter to _checkStart can be null, so there is no need to unwrap _lastPendingEventTimestamp.

  6. tarobins
    added 2 commits that reference this issue on Dec 22, 2022

    Avoid unnecessary unwrap of `_lastPendingEventTimestamp` which someti…

    b2743fc

    Avoid unnecessary unwrap of `_lastPendingEventTimestamp` which someti…

    7728232
  7. dnfield
    added a commit that references this issue on Feb 28, 2023

    Fix for flutter#112403 and b/249091367

    ce99b7d
  8. auto-submit
    closed this as completedin #121615on Feb 28, 2023
  9. auto-submit
    added a commit that references this issue on Feb 28, 2023

    Fix for #112403 and b/249091367 (#121615)

    c8aa37d

  10. github-actions commented on Mar 14, 2023

    @github-actions
    github-actionsbot
    on Mar 14, 2023

    This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

  11. github-actions
    locked as resolved and limited conversation to collaborators on Mar 14, 2023
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P2Important issues not at the top of the work listc: crashStack traces logged to the consolecustomer: dream (g3)f: gesturesflutter/packages/flutter/gestures repository.frameworkflutter/packages/flutter repository. See also f: labels.

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