fix(tab): avoid TabController crash when all conditional tabs are hidden#2241
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fix(tab): avoid TabController crash when all conditional tabs are hidden#2241cursor[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>
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Description
Fixes an app crash when every tab in a
TabBarorScrollableTabBaruses a conditionalvisiblebinding and all bindings evaluate to false at runtime.Bug and impact
Trigger: A screen with tabs where each item has
visible: ${someCondition}(or equivalent), and runtime evaluation sets every condition to false (e.g. user clears a filter that controlled all tab visibility).Impact:
handleConditionalTabs()calls_reinitializeTabController(), which createdTabController(length: 0). Flutter assertslength >= 1, causing a framework assertion crash.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()).notifyListeneron the placeholder controller when there are no visible tabs.ScrollableTabBarand clampselectedIndexwhen reinitializing (matchingTabBar).Validation
modules/ensemble/test/effective_tab_controller_length_test.dart.flutter test test/effective_tab_controller_length_test.dartfrommodules/ensembleperAGENTS.md.Duplicate check
gh pr list): no PR addressesTabController/ conditional tab visibility with zero visible items. Open drafts cover storage.clear ordering (fix(storage): defer binding updates until ensemble.storage.clear() completes #2231), upload batching (fix(upload): schedule all background batches with unique Workmanager work names #2239), upload cancelAll (fix(upload): complete cancelAll when some uploads already finished #2235), and navigateViewGroup clamping (fix(navigation): clamp navigateViewGroup index before PageController.jumpToPage #2238) — different code paths.TabController,handleConditionalTabs, and empty tab scenarios: none found.useIndexedTabproperty for smooth tab switching with lazy-loaded indexed building #2190 indexed tabs) did not handle the zero-length controller case.