fix(tab): avoid TabController crash when all conditional tabs are hidden#2255
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fix(tab): avoid TabController crash when all conditional tabs are hidden#2255cursor[bot] wants to merge 1 commit into
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When every tab has a conditional visible binding that evaluates to false, handleConditionalTabs() can leave zero visible items. TabController asserts length >= 1, which crashed the app during _reinitializeTabController. Use a placeholder length of 1 when no tabs are visible (build already returns shrink) and skip tab selection listeners until tabs return. Align ScrollableTabBar with the same guard and selectedIndex clamp. Co-authored-by: Sharjeel Yunus <sharjeelyunus@users.noreply.github.com>
This was referenced Jun 4, 2026
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Description
Resubmits the fix from #2241 (closed without merge on 2026-06-01). When every tab in a
TabBarorScrollableTabBaruses a conditionalvisiblebinding and all bindings evaluate to false at runtime,handleConditionalTabs()leaves zero visible items and_reinitializeTabController()createdTabController(length: 0), which violates Flutter’slength >= 1assertion and crashes the app.Bug and impact
Trigger: A screen with tabs where each item has
visible: ${someCondition}, and runtime evaluation sets every condition to false (e.g. filter state hides all tabs).Impact: Framework assertion failure / app crash during tab controller reinitialization.
Root cause
updateVisibleItems()can produce an empty visible tab list, but_initializeTabController()passeditems.lengthdirectly toTabControllerwithout guarding zero.Fix
effectiveTabControllerLength()so controller length is never below 1 when no tabs are visible (UI already returnsSizedBox.shrink()whenitems.isEmpty).notifyListeneron the placeholder controller when there are no visible tabs.ScrollableTabBarand clampselectedIndexwhen reinitializing.Validation
modules/ensemble/test/effective_tab_controller_length_test.dart.flutter test test/effective_tab_controller_length_test.dartfrommodules/ensemble.Duplicate check
cursor/critical-bug-remediation-adc5): same root cause and fix; closed without merge; reopen was not permitted via API.TabController.cursor/critical-bug-remediation-adc5contains commit77dc95b1(cherry-picked here asb0c06eb6).