avoid_conditional_hooks

v0.4.0 Warning Widget Best Practices

This rule flags hook calls (useState, useMemoized, useEffect, etc.) that appear inside if statements, ternary expressions, switch cases, or short-circuit operators (&&, ||). Hooks must be called in the exact same order on every build, and conditional execution breaks that guarantee.

Why use this rule

The hooks framework tracks state by call order, not by name. If a hook is skipped on one build because a condition is false, every subsequent hook shifts position and reads the wrong state. This leads to bizarre bugs where values swap between hooks or the app crashes with an index-out-of-range error. This is the same “Rules of Hooks” constraint from React.

See also: flutter_hooks | React Rules of Hooks

Don’t

class MyWidget extends HookWidget {
  final bool condition;

  @override
  Widget build(BuildContext context) {
    // Hook called conditionally — order changes between builds
    if (condition) {
      final value = useMemoized(() => 42);
    }
    return const Text('Hello');
  }
}

Do

class MyWidget extends HookWidget {
  final bool condition;

  @override
  Widget build(BuildContext context) {
    // Hook always called, conditional logic inside
    final value = useMemoized(() {
      if (condition) return 42;
      return 0;
    });
    return Text('$value');
  }
}

Configuration

To disable this rule:

plugins:
  many_lints:
    diagnostics:
      avoid_conditional_hooks: false