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Remove an assertion from CupertinoTabBar widget #42430

Closed
flutter/packages
#12546
Closed
Remove an assertion from CupertinoTabBar widget#42430
flutter/packages
#12546
Labels
P3Issues that are less important to the Flutter projecta: error messageError messages from the Flutter frameworkc: proposalA detailed proposal for a change to Flutterp: cupertino_uicupertino_ui package in flutter/packagespackageflutter/packages repository. See also p: labels.team-designOwned by Design Languages teamtriaged-designTriaged by Design Languages team

Description

@genert
genert
opened on Oct 10, 2019

Use case

When using CupertinoTabBar, it has an assertion that property "items" must consist 2 items at least.

See

flutter/packages/flutter/lib/src/cupertino/bottom_tab_bar.dart

Line 74 in 991153a

"Tabs need at least 2 items to conform to Apple's HIG",

Therefore when single item exists (we have a legitimise use case for that), the widget's assertion will fail resulting whole screen being bloody red in debug.

Proposal

I do not think Cupertino widgets should error when something does not conform to Apple's HIG. Warning message yes, but error? No thanks.

Therefore, I propose to remove the assertion and warn or log down for developer instead.

Activity

  1. BondarenkoStas
    added
    a: error messageError messages from the Flutter framework
    on Oct 10, 2019
  2. darrenaustin
    added
    p: cupertino_uicupertino_ui package in flutter/packages
    frameworkflutter/packages/flutter repository. See also f: labels.
    on Oct 11, 2019
  3. TahaTesser
    added
    c: proposalA detailed proposal for a change to Flutter
    on Mar 26, 2020

  4. DanielEdrisian commented on Oct 30, 2020

    @DanielEdrisian
    DanielEdrisian
    on Oct 30, 2020
    Contributor

    @xster this seems legit. Should we drop the assert?

  5. xster commented on Oct 31, 2020

    @xster
    xster
    on Oct 31, 2020
    Member

    Ya plausibly. Is it possible to have 1 tab item in Xcode?

  6. DanielEdrisian commented on Oct 31, 2020

    @DanielEdrisian
    DanielEdrisian
    on Oct 31, 2020
    Contributor

    Yes it is

  7. xster commented on Nov 2, 2020

    @xster
    xster
    on Nov 2, 2020
    Member

    Sure, removing that assert sounds reasonable to me.

  8. flutter-triage-bot
    added
    multiteam-retriage-candidate
    team-designOwned by Design Languages team
    triaged-designTriaged by Design Languages team
    on Jul 8, 2023

  9. thennothinghappened commented on Aug 6, 2023

    @thennothinghappened
    thennothinghappened
    on Aug 6, 2023

    Any update on this?

  10. flutter-triage-bot commented on Feb 12, 2024

    @flutter-triage-bot
    flutter-triage-botbot
    on Feb 12, 2024

    This issue is missing a priority label. Please set a priority label when adding the triaged-design label.

  11. flutter-triage-bot
    removed
    triaged-designTriaged by Design Languages team
    on Feb 12, 2024
  12. HansMuller
    added
    P3Issues that are less important to the Flutter project
    triaged-designTriaged by Design Languages team
    on Feb 14, 2024
  13. Hixie
    removed
    multiteam-retriage-candidate
    on Mar 6, 2024
  14. Piinks
    added
    packageflutter/packages repository. See also p: labels.
    and removed
    frameworkflutter/packages/flutter repository. See also f: labels.
    on Aug 18, 2026
  15. auto-submit
    added a commit that references this issue on Aug 25, 2026

    [cupertino_ui] Remove two items assert to allow CupertinoTabBar to ha…

    9f595f3
  16. auto-submit
    closed this as completedin packages#12546on Aug 25, 2026
  17. danielleon-cmd
    added a commit that references this issue on Aug 27, 2026

    [cupertino_ui] Remove two items assert to allow CupertinoTabBar to ha…

    4128a99
  18. jagadeesh8682
    added a commit that references this issue on Sep 2, 2026

    [cupertino_ui] Remove two items assert to allow CupertinoTabBar to ha…

    7bbad64

  19. github-actions commented on Sep 8, 2026

    @github-actions
    github-actionsbot
    on Sep 8, 2026 – with GitHub Actions

    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.

  20. github-actions
    locked as resolved and limited conversation to collaborators on Sep 8, 2026
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