source-command-flutter-build

name	source-command-flutter-build
description	Fix Dart analyzer errors and Flutter build failures incrementally. Invokes the dart-build-resolver agent for minimal, surgical fixes.

source-command-flutter-build

Use this skill when the user asks to run the migrated source command flutter-build.

Command Template

Flutter Build and Fix

This command invokes the dart-build-resolver agent to incrementally fix Dart/Flutter build errors with minimal changes.

What This Command Does

1. Run Diagnostics: Execute flutter analyze, flutter pub get
2. Parse Errors: Group by file and sort by severity
3. Fix Incrementally: One error at a time
4. Verify Each Fix: Re-run analysis after each change
5. Report Summary: Show what was fixed and what remains

When to Use

Use /flutter-build when:

• flutter analyze reports errors
• flutter build fails for any platform
• dart pub get / flutter pub get fails with version conflicts
• build_runner fails to generate code
• After pulling changes that break the build

Diagnostic Commands Run

# Analysis
flutter analyze 2>&1

# Dependencies
flutter pub get 2>&1

# Code generation (if project uses build_runner)
dart run build_runner build --delete-conflicting-outputs 2>&1

# Platform builds
flutter build apk 2>&1
flutter build web 2>&1

Example Session

User: /flutter-build

Agent:
# Flutter Build Resolution

## Initial Diagnostics

```
$ flutter analyze
Analyzing project...

  error • lib/features/user/data/user_repository_impl.dart:34:16 •
    A value of type 'String?' can't be assigned to a variable of type 'String'. •
    invalid_assignment

  error • lib/features/cart/presentation/cart_page.dart:58:5 •
    The method 'add' isn't defined for the type 'List<Item>'.
    Try correcting the name to the name of an existing method, or defining a method named 'add'. •
    undefined_method

2 errors found.
```

## Fix 1: Null Safety

File: lib/features/user/data/user_repository_impl.dart:34
Error: A value of type 'String?' can't be assigned to type 'String'

Changed:
```dart
final id = response.id;
```
To:
```dart
final id = response.id ?? '';
```

```
$ flutter analyze
1 error found.
```

## Fix 2: Immutable List

File: lib/features/cart/presentation/cart_page.dart:58
Error: The method 'add' isn't defined for the type 'List<Item>'
Cause: State holds an unmodifiable list; mutation goes through Cubit

Changed:
```dart
state.items.add(item);
```
To:
```dart
context.read<CartCubit>().addItem(item);
// Note: Cubit exposes named methods (addItem, removeItem);
// .add(event) is the BLoC event API — don't mix them.
```

```
$ flutter analyze
No issues found!
```

## Final Verification

```
$ flutter test
All tests passed.
```

## Summary

| Metric | Count |
|--------|-------|
| Analysis errors fixed | 2 |
| Files modified | 2 |
| Remaining issues | 0 |

Build Status: PASS ✓

Common Errors Fixed

Error	Typical Fix
A value of type 'X?' can't be assigned to 'X'	Add ?? default or null guard
The name 'X' isn't defined	Add import or fix typo
Non-nullable instance field must be initialized	Add initializer or late
Version solving failed	Adjust version constraints in pubspec.yaml
Missing concrete implementation of 'X'	Implement missing interface method
build_runner: Part of X expected	Delete stale .g.dart and rebuild

Fix Strategy

1. Analysis errors first — code must be error-free
2. Warning triage second — fix warnings that could cause runtime bugs
3. pub conflicts third — fix dependency resolution
4. One fix at a time — verify each change
5. Minimal changes — don't refactor, just fix

Stop Conditions

The agent will stop and report if:

• Same error persists after 3 attempts
• Fix introduces more errors
• Requires architectural changes
• Package upgrade conflicts need user decision

Related Commands

• /flutter-test — Run tests after build succeeds
• /flutter-review — Review code quality
• /verify — Full verification loop

Related

• Agent: agents/dart-build-resolver.md
• Skill: skills/flutter-dart-code-review/