rugged-gemini: Skill for Claude Code

Flutter Idioms and Patterns (Riverpod 3)

Flutter = UI toolkit first — performance is first-class. const widgets + immutable data keep render tree efficient. Riverpod 3 = canonical state management: compile-safe, testable without BuildContext, no implicit global state, automatic retry + pause/resume.

Code generation mandatory. All providers use @riverpod/@Riverpod(keepAlive: true) with riverpod_generator + build_runner. Catches type errors, missing overrides, broken provider graphs at compile time.

# pubspec.yaml
dependencies:
  flutter_riverpod: 3.2.1
  riverpod_annotation: 4.0.2

dev_dependencies:
  riverpod_generator: 4.0.3
  build_runner: # latest
  riverpod_lint: # latest

Scope: Flutter/Dart coding idioms. Layout: @.gemini/skills/project-structure-flutter/SKILL.md. Tests: GEMINI.md § Testing Strategy. Error handling: GEMINI.md § Error Handling Principles.

const Constructors — Everywhere

// ✅ const constructor — rebuild-safe
class TaskCard extends StatelessWidget {
    const TaskCard({super.key, required this.task});
    final Task task;
}

// Usage — compile-time constant
const TaskCard(task: myTask)

Rules: every StatelessWidget with no mutable state = const constructor. Pass const at call site. Enable prefer_const_constructors lint.

Widget Decomposition

1. Extract widget when subtree has distinct responsibilities:

   // ✅ Each subtree = named widget with const constructor
   @override
   Widget build(BuildContext context) {
       return Column(children: [
           const TaskHeader(),
           const TaskList(),
           const TaskFooter(),
       ]);
   }
   

2. Never use builder methods (_buildHeader()) — they skip const optimization. Extract proper widgets.

3. build under ~30 lines — decompose if longer.

Immutable Data with freezed

All domain models immutable via freezed: value objects with copyWith, union/sealed types, generated ==/hashCode/toString.