fix: guard BuildContext usage across async gaps in task, ticket, and workspace screens

[Muneerali199]

Summary

Fixes #223

Resolves use_build_context_synchronously lint warnings in three screens where ScaffoldMessenger.of(context) was called after an await without a mounted guard.

Problem

After an await (e.g., await Navigator.push(...)), the widget may have been disposed. Calling ScaffoldMessenger.of(context) on a stale BuildContext can cause a runtime crash:

FlutterError: Looking up a deactivated widget's ancestor is unsafe.

The analyzer correctly flagged these with use_build_context_synchronously.

Files Changed

File	Issue
lib/screens/tasks/task_screen.dart	ScaffoldMessenger.of(context) after await Navigator.push in FAB onPressed
lib/screens/tickets/ticket_screen.dart	Same pattern in FAB onPressed
lib/screens/workspace/workspace_screen.dart	Three .then((result) async {}) callbacks after await calls

Fix Applied

Two complementary techniques used per Flutter best practices:

1. Pre-capture the messenger before the await:

   final messenger = ScaffoldMessenger.of(context);
   final result = await Navigator.push(...);
   if (result == true && mounted) {
     messenger.showSnackBar(...); // safe: captured before await
   }

2. mounted guard in .then() callbacks (workspace screen):

   .then((result) async {
     if (result == true) {
       await supabaseService.loadTeamMembers(...);
       if (mounted) {
         ScaffoldMessenger.of(context).showSnackBar(...);
       }
     }
   });

Before / After

Before (flutter analyze):

info - Don't use 'BuildContext's across async gaps - task_screen.dart:178 - use_build_context_synchronously
info - Don't use 'BuildContext's across async gaps - ticket_screen.dart:165 - use_build_context_synchronously
info - Don't use 'BuildContext's across async gaps - workspace_screen.dart:83 - use_build_context_synchronously
info - Don't use 'BuildContext's across async gaps - workspace_screen.dart:109 - use_build_context_synchronously
info - Don't use 'BuildContext's across async gaps - workspace_screen.dart:135 - use_build_context_synchronously

After (flutter analyze lib/screens/tasks/task_screen.dart lib/screens/tickets/ticket_screen.dart lib/screens/workspace/workspace_screen.dart):

23 issues found.

Zero use_build_context_synchronously warnings remaining in these files.

Checklist

• flutter analyze run — no new warnings introduced
• All use_build_context_synchronously warnings in the three files resolved
• Fix follows Flutter official guidance (pre-capture or mounted check)
• No logic changes — only safety guards added

Summary by CodeRabbit

• Bug Fixes
  • Fixed potential crashes when displaying success or error notifications after navigating away from screens.
  • Improved stability when creating tasks, tickets, or meetings by ensuring notifications only display when screens are active.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: 9dd44177-622c-465f-9cdf-6ed17135d614

📥 Commits

Reviewing files that changed from the base of the PR and between 5afe656 and b9ef95b.

📒 Files selected for processing (3)

• lib/screens/tasks/task_screen.dart
• lib/screens/tickets/ticket_screen.dart
• lib/screens/workspace/workspace_screen.dart

---

Walkthrough

This PR fixes a critical bug where BuildContext is accessed across async gaps without verifying widget mounting, causing "Looking up a deactivated widget's ancestor is unsafe" crashes during navigation. The fix adds mounted checks before showing SnackBars and other UI feedback in task, ticket, and workspace screens.

Changes

Cohort / File(s)	Summary
BuildContext Safety Fixes lib/screens/tasks/task_screen.dart, lib/screens/tickets/ticket_screen.dart, lib/screens/workspace/workspace_screen.dart	Added mounted guards before accessing context in error handlers, success callbacks, and post-async operations. Introduced local ScaffoldMessenger instances captured before async calls to ensure safe UI feedback delivery when widgets remain mounted.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested labels

Dart/Flutter

Poem

🐰 A widget unmounted, context alas—
We caught the crash before it could pass!
With mounted checks standing guard so true,
Our SnackBars now know what to do. ✨

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the primary fix: guarding BuildContext usage across async gaps with mounted checks and pre-captured messenger instances in three screen files.
Linked Issues check	✅ Passed	All coding requirements from issue #223 are met: seven instances of unsafe BuildContext usage after async operations have been addressed with mounted guards or pre-captured messenger instances across the three specified files.
Out of Scope Changes check	✅ Passed	All changes are directly related to fixing the BuildContext safety issue in the three specified files; no unrelated modifications or logic changes were introduced.

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