add-dart-lint-validation-rule

Add a New Validation Rule and Flag

Use this skill when you need to add a new validation rule to the dart_skills_lint package, expose it as a toggleable CLI flag, and verify its behavior.

---

🛠️ Step-by-Step Implementation

1. Create the Rule Class

Create a new file in lib/src/rules/ extending SkillRule.

// lib/src/rules/my_new_rule.dart

import '../models/analysis_severity.dart';
import '../models/skill_context.dart';
import '../models/skill_rule.dart';
import '../models/validation_error.dart';

class MyNewRule extends SkillRule {
  MyNewRule({super.severity});

  @override
  Future<List<ValidationError>> validate(SkillContext context) async {
    final errors = <ValidationError>[];
    // Add validation logic here using context.rawContent or context.directory
    return errors;
  }
}

2. Register the Rule in lib/src/rule_registry.dart

Add a new CheckType instance to RuleRegistry.allChecks list. This automatically exposes it as a CLI flag.

// lib/src/rule_registry.dart in allChecks list

  const CheckType(
    name: MyNewRule.ruleName,
    defaultSeverity: MyNewRule.defaultSeverity,
    help: 'Description of what the rule does for CLI help.',
  ),

Then, add a case to RuleRegistry.createRule to instantiate your rule:

// lib/src/rule_registry.dart in createRule method

  static SkillRule? createRule(String name, AnalysisSeverity severity) {
    switch (name) {
      // ... other rules
      case MyNewRule.ruleName:
        return MyNewRule(severity: severity);
      default:
        return null;
    }
  }

3. Handle Disabled by Default Rules (If applicable)

If the rule is disabled by default (defaultSeverity: AnalysisSeverity.disabled), passing the flag --check-my-new-rule will automatically enable it with AnalysisSeverity.error severity (handled in entry_point.dart).

---

🧪 Testing the New Rule

You must write automated tests verifying your rule triggers when it should and skips when it shouldn't.