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Agent skill

Flutter Dispose Timer Test Failure

by divinevideo in divinevideo/divine-mobile

Fix Flutter test failure "A Timer is still pending even after the widget tree was disposed".

MPL-2.0Auto-check passedMobile

Install Flutter Dispose Timer Test Failure

skills CLI
$ npx skills add divinevideo/divine-mobile --skill flutter-dispose-timer-test-failure -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install divinevideo/divine-mobile flutter-dispose-timer-test-failure --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/divinevideo/divine-mobile.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/flutter-dispose-timer-test-failure .claude/skills/flutter-dispose-timer-test-failure && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
flutter-dispose-timer-test-failure
GitHub stars
265
Token cost
~919 tokens
SKILL.md length
266 words
Files
1
Skills in repo
103
Repo updated
First seen
Licence
MPL-2.0

At a glance

Fix Flutter test failure "A Timer is still pending even after the widget tree was disposed".

  • Works in 3 steps: Identify the problematic code → Move cleanup to deactivate() → Understand the lifecycle difference
  • Widget tests fail with timer pending error
  • SKILL.md covers Problem, Context / Trigger Conditions, Solution and Verification, plus 3 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Flutter Dispose Timer Test Failure is an agent skill from divinevideo/divine-mobile. Fix Flutter test failure "A Timer is still pending even after the widget tree was disposed". Use when: (1) Widget tests fail with timer pending error, (2) dispose() contains Future(), Future.delayed(), or Timer calls, (3) Riverpod provider modifications in dispose(). The fix is to use deactivate() instead of dispose() for cleanup that might trigger async work.

Its SKILL.md is about 920 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Mobile, covering Failing and flaky tests and Cross-platform mobile apps. It works with Flutter. The licence is MPL-2.0.

When your agent uses it

  • Widget tests fail with timer pending error
  • Dispose() contains Future()
  • Future.delayed()
  • Riverpod provider modifications in dispose()

Example prompts

  • “A Timer is still pending even after the widget tree was disposed”
  • “/flutter-dispose-timer-test-failure”

Workflow steps

3 steps, taken from the step headings in SKILL.md.

  1. Identify the problematic code
  2. Move cleanup to deactivate()
  3. Understand the lifecycle difference

What it can do on your machine

Read from SKILL.md and the folder at commit 8d5fbf2. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are dart).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Links to these hosts (documentation or services it may open):

    • api.flutter.dev
    • docs.flutter.dev

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Flutter Dispose Timer Test Failure loads about 919 tokens when it runs. Until then it costs about 99 tokens; SKILL.md has 266 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~99
When it runs · the whole SKILL.md, loaded when a task matches
~919

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from divinevideo/divine-mobile at commit 8d5fbf2, republished under its MPL-2.0 licence (© divinevideo). 266 words, ~919 tokens.

Download SKILL.mdSave it as .claude/skills/flutter-dispose-timer-test-failure/SKILL.md (or your agent's skills folder).
name
flutter-dispose-timer-test-failure
description
Fix Flutter test failure "A Timer is still pending even after the widget tree was disposed". Use when: (1) Widget tests fail with timer pending error, (2) dispose() contains Future(), Future.delayed(), or Timer calls, (3) Riverpod provider modifications in dispose(). The fix is to use deactivate() instead of dispose() for cleanup that might trigger async work.
author
Claude Code
version
1.0.0
date
2025-01-26

Flutter Dispose Timer Test Failure

Problem

Flutter widget tests fail with the error "A Timer is still pending even after the widget tree was disposed" when dispose() contains Future-based cleanup code.

Context / Trigger Conditions

  • Test error: A Timer is still pending even after the widget tree was disposed
  • Widget's dispose() method contains:
    • Future(() => ...)
    • Future.delayed(...)
    • Timer(...) or Timer.periodic(...)
    • Riverpod ref.read(provider.notifier).someMethod() wrapped in Future
  • Tests pass individually but fail when run together
  • Error appears at end of test, not during widget interaction

Solution

Step 1: Identify the problematic code

Look for patterns like this in your widget:

dart
// BAD: Creates pending timer that test framework detects
@override
void dispose() {
  final notifier = _overlayNotifier;
  if (notifier != null) {
    Future(() => notifier.setSettingsOpen(false));  // <- Problem!
  }
  super.dispose();
}
Step 2: Move cleanup to deactivate()

Use deactivate() instead of dispose() and remove the Future wrapper:

dart
// GOOD: Runs synchronously before widget is removed
@override
void deactivate() {
  _overlayNotifier?.setSettingsOpen(false);  // Direct call, no Future
  super.deactivate();
}
Step 3: Understand the lifecycle difference
  • deactivate(): Called when widget is removed from tree, but State might be reinserted
  • dispose(): Called when State will never build again, permanent cleanup

For most notification/provider cleanup, deactivate() is appropriate.

Verification

  1. Run the specific test that was failing
  2. Run the full test suite
  3. Verify no "Timer is still pending" errors

Example

Before (causes test failure):
dart
class _SettingsScreenState extends ConsumerState<SettingsScreen> {
  OverlayNotifier? _overlayNotifier;

  @override
  void dispose() {
    final notifier = _overlayNotifier;
    if (notifier != null) {
      // This Future creates a pending timer!
      Future(() => notifier.setSettingsOpen(false));
    }
    super.dispose();
  }
}
After (tests pass):
dart
class _SettingsScreenState extends ConsumerState<SettingsScreen> {
  OverlayNotifier? _overlayNotifier;

  @override
  void deactivate() {
    // Synchronous call, no timer created
    _overlayNotifier?.setSettingsOpen(false);
    super.deactivate();
  }
}

Notes

  • The original Future(() => ...) pattern is often used to defer provider modifications until after the current build phase, avoiding "Cannot modify provider during build" errors
  • If you need deferred execution, consider WidgetsBinding.instance.addPostFrameCallback instead, though this also creates timers that can fail tests
  • For Riverpod, modifying providers in deactivate() is usually safe since the widget tree is being torn down, not built
  • This issue often surfaces when multiple tests run sequentially, as the test framework checks for pending timers between tests

References

© divinevideo, MPL-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .agents/skills/flutter-dispose-timer-test-failure of divinevideo/divine-mobile.

Open the folder on GitHubat commit 8d5fbf2

Compare with similar skills

Flutter Dispose Timer Test Failure next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Flutter Dispose Timer Test Failure compared with similar skills
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Works with

Categories

Questions about Flutter Dispose Timer Test Failure

What does Flutter Dispose Timer Test Failure do?

Fix Flutter test failure "A Timer is still pending even after the widget tree was disposed". Flutter Dispose Timer Test Failure is an agent skill from divinevideo/divine-mobile. Fix Flutter test failure "A Timer is still pending even after the widget tree was disposed".

When should I use Flutter Dispose Timer Test Failure?

Flutter Dispose Timer Test Failure fits situations like: widget tests fail with timer pending error; dispose() contains Future(); future.delayed(); riverpod provider modifications in dispose().

How do I install Flutter Dispose Timer Test Failure in Claude Code?

Run `npx skills add divinevideo/divine-mobile --skill flutter-dispose-timer-test-failure -a claude-code`. Or copy the skill folder (.agents/skills/flutter-dispose-timer-test-failure in divinevideo/divine-mobile) into .claude/skills/flutter-dispose-timer-test-failure in your project. Claude Code loads it when a task matches its description.

How do I install Flutter Dispose Timer Test Failure in Codex?

Run `npx skills add divinevideo/divine-mobile --skill flutter-dispose-timer-test-failure -a codex`. Or copy the skill folder (.agents/skills/flutter-dispose-timer-test-failure in divinevideo/divine-mobile) into .agents/skills/flutter-dispose-timer-test-failure in your project. Codex loads it when a task matches its description.

Can I use Flutter Dispose Timer Test Failure in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add divinevideo/divine-mobile --skill flutter-dispose-timer-test-failure -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/flutter-dispose-timer-test-failure, .gemini/skills/flutter-dispose-timer-test-failure, .github/skills/flutter-dispose-timer-test-failure and .opencode/skills/flutter-dispose-timer-test-failure in your project.

What does Flutter Dispose Timer Test Failure need to run?

SKILL.md names no scripts, command-line tools or credentials: Flutter Dispose Timer Test Failure is instructions for the agent only.

Does Flutter Dispose Timer Test Failure access the network?

SKILL.md names 2 domains. As links in the text: api.flutter.dev and docs.flutter.dev. This is read from the text; nothing was executed.

Is Flutter Dispose Timer Test Failure safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Flutter Dispose Timer Test Failure use?

Flutter Dispose Timer Test Failure is published under the MPL-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Flutter Dispose Timer Test Failure use?

About 919 tokens (SKILL.md is roughly 3.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Flutter Dispose Timer Test Failure?

Skills that share tags, products or a category with Flutter Dispose Timer Test Failure: Frb Fix CI (fzyzcjy/flutter_rust_bridge, 5.4k stars), Green Gate (VeryGoodOpenSource/vgv-ai-flutter-plugin, 169 stars), Diagnosing Bugs (getsentry/sentry-dart, 873 stars) and Flutter Testing (MADTeacher/mad-agents-skills, 110 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Flutter Dispose Timer Test Failure?

divinevideo (a GitHub organization) maintains it in divinevideo/divine-mobile, which has 265 GitHub stars. The repository holds 103 skills in this directory. The repository was last updated on October 7, 2026.

Source: divinevideo/divine-mobile on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.