Nested Shell Navigation

When tab shell patterns or independent back histories are in scope, use nested navigators or ShellRoute.

Patterns

• Tab Shells: Use a parent routing mechanism (like ShellRoute or StatefulShellRoute in go_router) to coordinate persistent UI around changing nested content.
• Independent Back Stacks: Keep each tab's history isolated so navigating deep into one tab doesn't affect the history of others.

Implementation Approaches

• StatefulShellRoute: Preferred in modern go_router usage as it manages state restoration and branch switching automatically.
• Nested Navigators: Manual implementation involves assigning unique GlobalKey<NavigatorState> to each tab's Navigator.

Best Practices

• In-Memory Tab Preservation vs Process Restoration: In-memory caching (via StatefulShellRoute.indexedStack, IndexedStack, or AutomaticKeepAliveClientMixin) preserves scroll position and input state during live tab switches, but does NOT survive OS process termination. Surviving process death requires explicit restoration IDs (RootRestorationScope, restorationId), RestorableProperty registration, and framework state restoration configuration.
• Hero Tag Scoping: When tabs stay mounted in memory, ensure Hero tags in offstage tabs do not collide with active or newly pushed routes. Scope tags by tab branch or conditionally disable offstage Heroes.
• Testing: Verify back behavior both within a nested route (popping a tab's stack) and across tabs (returning to a default tab or exiting the app).