feat: Add scaffolding for 30 ESLint core rules (Batch 1 - Possible Problems)

[delino]

Summary

This PR implements scaffolding for the first batch of 30 foundational ESLint core rules from the "Possible Problems" category. These rules are frequently used and don't depend on other rules, making them ideal for the initial implementation.

Motivation

As part of the larger effort to port 150+ ESLint rules to RSLint, this PR focuses on implementing the foundational "Possible Problems" category rules. These rules catch common programming errors and are essential for any JavaScript/TypeScript linter.

Changes

Rules Added (30 total)

All rules in the "Possible Problems" category:

1. array-callback-return - Enforce return statements in array callbacks
2. constructor-super - Require super() calls in constructors
3. for-direction - Enforce for loop update clause moving in correct direction
4. getter-return - Enforce return statements in getters
5. no-async-promise-executor - Disallow async promise executor
6. no-class-assign - Disallow reassigning class members
7. no-compare-neg-zero - Disallow comparing against -0
8. no-cond-assign - Disallow assignment operators in conditional expressions
9. no-const-assign - Disallow reassigning const variables
10. no-constant-binary-expression - Disallow expressions where operation doesn't affect value
11. no-constant-condition - Disallow constant expressions in conditions
12. no-constructor-return - Disallow returning value from constructor
13. no-control-regex - Disallow control characters in regular expressions
14. no-debugger - Disallow debugger statements
15. no-dupe-args - Disallow duplicate arguments in function definitions
16. no-dupe-class-members - Disallow duplicate class members
17. no-dupe-else-if - Disallow duplicate conditions in if-else-if chains
18. no-dupe-keys - Disallow duplicate keys in object literals
19. no-duplicate-case - Disallow duplicate case labels
20. no-duplicate-imports - Disallow duplicate module imports
21. no-empty-character-class - Disallow empty character classes in regex
22. no-empty-pattern - Disallow empty destructuring patterns
23. no-ex-assign - Disallow reassigning exceptions in catch clauses
24. no-fallthrough - Disallow fallthrough of case statements
25. no-func-assign - Disallow reassigning function declarations
26. no-import-assign - Disallow assigning to imported bindings
27. no-inner-declarations - Disallow variable or function declarations in nested blocks
28. no-invalid-regexp - Disallow invalid regular expression strings in RegExp
29. no-irregular-whitespace - Disallow irregular whitespace
30. no-loss-of-precision - Disallow number literals that lose precision

Technical Implementation

File Structure:
Each rule follows the established RSLint pattern:

internal/rules/[rule_name]/
├── [rule_name].go       # Rule implementation scaffolding
└── [rule_name]_test.go  # Test template with placeholders

Code Generation:

• Leveraged automated tooling from PR feat: Automated rule scaffolding tools for ESLint/TypeScript-ESLint migration #14
• Used scripts/generate-rule.go in batch mode
• Created batch file: scripts/examples/eslint-possible-problems-batch1.txt
• Auto-registered all rules using scripts/register-rule.go -auto

Build Status:

• ✅ All code compiles successfully
• ✅ All 30 rules are registered in the global rule registry
• ✅ No build errors or warnings
• ✅ Ready for implementation

Implementation Status

🚧 DRAFT - Scaffolding Only

This PR provides the complete scaffolding and structure for all 30 rules. Each rule currently contains:

• ✅ Complete package structure
• ✅ Rule variable definition
• ✅ Empty Run function with TODO comments
• ✅ Test file template with placeholders
• ✅ Registered in global rule registry

What's Next:

The following work needs to be completed before this PR is ready for review:

• Implement rule logic for each of the 30 rules
• Port comprehensive test cases from ESLint test suite
• Add autofix functionality where ESLint provides it
• Verify behavior matches ESLint exactly
• Add documentation for each rule
• Run full test suite and ensure all tests pass

Testing Plan

Once implementation is complete:

1. Unit Tests: Port ESLint's test cases for each rule
2. Integration Tests: Verify rules work correctly in real codebases
3. Autofix Tests: Ensure autofixes produce correct code
4. Compatibility Tests: Confirm behavior matches ESLint

Documentation & Resources

• ESLint Rules Reference: https://eslint.org/docs/latest/rules/
• ESLint Source Code: https://github.com/eslint/eslint/tree/main/lib/rules
• RSLint Architecture: See architecture.md
• Rule Scaffolding Guide: See docs/RULE_SCAFFOLDING_GUIDE.md

Related Work

• Builds on: PR feat: Automated rule scaffolding tools for ESLint/TypeScript-ESLint migration #14 (Automated rule scaffolding tools)
• Part of: Larger effort to port 150+ ESLint rules to RSLint
• Category: Possible Problems (high priority foundational rules)

Files Changed

New Files (61 total)

• 60 rule files (30 rules × 2 files each: implementation + tests)
• 1 batch configuration file

Modified Files (2 total)

• internal/config/config.go - Registered all 30 new core rules
• scripts/register-rule.go - Fixed unused import issue

Total Lines Added: ~2,169 lines of scaffolding code

Success Criteria

Before moving out of draft:

• All 30 rules have complete implementations
• All rules pass their test suites
• Autofixes work correctly where applicable
• Documentation is complete
• Code review feedback is addressed
• Build and all tests pass

Notes for Reviewers

This is a DRAFT PR containing only scaffolding. The primary purpose is to:

1. Establish the structure for all 30 rules
2. Ensure the build system works correctly
3. Verify the registration process
4. Provide a foundation for implementation

Please do not merge until all rule implementations are complete and tested.

---

🤖 Generated with Claude Code

Co-Authored-By: Claude noreply@anthropic.com

[kdy1]

🤖 This pull request has been linked to DevBird Task #895

View the task details and manage the automated development workflow in DevBird.

Learn more about DevBird here or the announcement blog post here.

[kdy1]

📋 DevBird Task Prompt

Port the first batch of foundational ESLint core rules that are frequently used and don't depend on other rules.

Objective

Implement 30 high-priority ESLint core rules from the "Possible Problems" category in Go for RSLint.

Documentation & Resources

• ESLint Rules Reference: https://eslint.org/docs/latest/rules/
• ESLint Source Code: https://github.com/eslint/eslint/tree/main/lib/rules
• Each rule documentation: https://eslint.org/docs/latest/rules/[rule-name]
• RSLint Rule Pattern: See internal/rules/dot_notation/dot_notation.go
• TypeScript-Go AST: https://github.com/microsoft/typescript-go

Rules to Port (Batch 1 - Possible Problems)

1. array-callback-return - Enforce return statements in array callbacks
2. constructor-super - Require super() calls in constructors
3. for-direction - Enforce for loop update clause moving in correct direction
4. getter-return - Enforce return statements in getters
5. no-async-promise-executor - Disallow async promise executor
6. no-class-assign - Disallow reassigning class members
7. no-compare-neg-zero - Disallow comparing against -0
8. no-cond-assign - Disallow assignment operators in conditional expressions
9. no-const-assign - Disallow reassigning const variables
10. no-constant-binary-expression - Disallow expressions where operation doesn't affect value
11. no-constant-condition - Disallow constant expressions in conditions
12. no-constructor-return - Disallow returning value from constructor
13. no-control-regex - Disallow control characters in regular expressions
14. no-debugger - Disallow debugger statements
15. no-dupe-args - Disallow duplicate arguments in function definitions
16. no-dupe-class-members - Disallow duplicate class members
17. no-dupe-else-if - Disallow duplicate conditions in if-else-if chains
18. no-dupe-keys - Disallow duplicate keys in object literals
19. no-duplicate-case - Disallow duplicate case labels
20. no-duplicate-imports - Disallow duplicate module imports
21. no-empty-character-class - Disallow empty character classes in regex
22. no-empty-pattern - Disallow empty destructuring patterns
23. no-ex-assign - Disallow reassigning exceptions in catch clauses
24. no-fallthrough - Disallow fallthrough of case statements
25. no-func-assign - Disallow reassigning function declarations
26. no-import-assign - Disallow assigning to imported bindings
27. no-inner-declarations - Disallow variable or function declarations in nested blocks
28. no-invalid-regexp - Disallow invalid regular expression strings in RegExp
29. no-irregular-whitespace - Disallow irregular whitespace
30. no-loss-of-precision - Disallow number literals that lose precision

Technical Requirements

• Create directory for each rule: internal/rules/[rule_name]/
• Implement rule logic in [rule_name].go
• Add comprehensive tests in [rule_name]_test.go
• Register rules in internal/config/rule_registry.go
• Follow AST patterns from existing dot_notation rule
• Include autofixes where ESLint provides them
• Support all rule options from ESLint

Success Criteria

• All 30 rules compile successfully
• Test cases pass (ported from ESLint test suite)
• Rules correctly identify violations
• Autofixes work where applicable
• Rules are registered and can be enabled in config

---

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[claude]

Pull Request Review: PR #18 - Scaffolding for 30 ESLint Core Rules

Summary

This PR successfully implements scaffolding for 30 foundational ESLint core rules from the "Possible Problems" category. The automated generation approach using the tooling from PR #14 is well-executed and provides a solid foundation for implementation.

✅ Strengths

1. Excellent Use of Automation

• Leveraged the automated rule scaffolding tools effectively
• Batch generation approach reduces manual errors and ensures consistency
• The batch configuration file (eslint-possible-problems-batch1.txt) is well-documented and reusable

2. Consistent Structure

• All 30 rules follow the established RSLint pattern perfectly
• Package naming (snake_case) is consistent across all rules
• File organization matches the project's architecture guidelines
• Each rule includes both implementation and test file templates

3. Good Project Management

• Clear PR description with comprehensive details
• Appropriate use of DRAFT status
• Well-defined success criteria
• Detailed implementation checklist for next steps

4. Proper Registration

• All 30 rules are correctly registered in internal/config/config.go
• Import statements are properly added
• Registration follows the established pattern

⚠️ Issues Found

1. Critical: Duplicate Registration in registerAllEslintImportPluginRules() (Line 450-456)

Location: internal/config/config.go:450-456

func registerAllEslintImportPluginRules() {
	for _, rule := range importPlugin.GetAllRules() {
		GlobalRuleRegistry.Register(rule.Name, rule)
		GlobalRuleRegistry.Register("import/no-self-import", no_self_import.NoSelfImportRule)
		GlobalRuleRegistry.Register("import/no-webpack-loader-syntax", no_webpack_loader_syntax.NoWebpackLoaderSyntax)
	}
}

Problem: The two manual registrations inside the loop will be executed multiple times, once for each rule in importPlugin.GetAllRules(). This causes:

• Inefficient repeated registrations
• Potential confusion about rule registration order
• Code that doesn't follow the pattern used elsewhere

Fix: Move the manual registrations outside the loop:

func registerAllEslintImportPluginRules() {
	for _, rule := range importPlugin.GetAllRules() {
		GlobalRuleRegistry.Register(rule.Name, rule)
	}
	GlobalRuleRegistry.Register("import/no-self-import", no_self_import.NoSelfImportRule)
	GlobalRuleRegistry.Register("import/no-webpack-loader-syntax", no_webpack_loader_syntax.NoWebpackLoaderSyntax)
}

2. Minor: Generic Placeholder AST Node Type

Location: All generated rule files (e.g., array_callback_return.go:18)

return rule.RuleListeners{
	ast.KindFunctionDeclaration: func(node *ast.Node) {
		// TODO: Implement rule logic for FunctionDeclaration

Issue: All rules use ast.KindFunctionDeclaration as a placeholder, which is not semantically correct for many of these rules. While this is scaffolding and marked with TODO, it would be better to have the correct AST node types from the start.

Examples of incorrect node types:

• no-debugger should listen to ast.KindDebuggerStatement, not KindFunctionDeclaration
• no-compare-neg-zero should listen to ast.KindBinaryExpression
• no-duplicate-imports should listen to ast.KindImportDeclaration
• for-direction should listen to ast.KindForStatement

Recommendation: Consider using the -ast-nodes flag when generating rules to specify the correct node types upfront.

3. Minor: Unused Import After Fix

Location: scripts/register-rule.go

The diff shows:

-import (

This suggests an unused import was removed, which is good. However, ensure this doesn't break the script's functionality.

📊 Code Quality Assessment

Structure: ✅ Excellent

• Follows established patterns from docs/RULE_SCAFFOLDING_GUIDE.md
• Consistent with existing rules like dot_notation
• Proper package structure and file organization

Best Practices: ✅ Good

• Uses TODO comments appropriately
• Follows Go naming conventions
• Proper separation of concerns (implementation + tests)

Test Coverage: ⚠️ Needs Implementation

• Test templates are present but contain only placeholder cases
• No actual test cases ported from ESLint yet
• This is expected for DRAFT status

🔒 Security Considerations

No security concerns identified. This is scaffolding code with no actual rule logic implemented yet.

⚡ Performance Considerations

No performance concerns. The current scaffolding is minimal and follows the established patterns that have proven performant in existing rules.

🧪 Testing

Current State:

• ✅ Code compiles successfully (as stated in PR description)
• ✅ All rules are registered
• ⚠️ No actual test cases implemented yet (expected for DRAFT)

Before Final Review:

The following must be completed:

1. Implement rule logic for all 30 rules
2. Port comprehensive test cases from ESLint
3. Verify tests pass for all rules
4. Add autofix functionality where applicable

📝 Recommendations

Before Moving Out of DRAFT:

1. Fix the critical registration bug in registerAllEslintImportPluginRules() immediately
2. Implement rules incrementally - Consider implementing a few rules completely before adding all 30
3. Add proper AST node types when implementing each rule
4. Port ESLint test cases - Use the -fetch flag or manually port from ESLint's test suite
5. Add documentation - Include brief descriptions in each rule's comment
6. Consider adding rule messages - Define the error messages that will be shown to users

Implementation Priority Suggestions:

Start with simpler rules that have clear, well-defined behavior:

1. no-debugger - Very simple, just detect debugger statements
2. no-compare-neg-zero - Simple comparison check
3. no-dupe-keys - Object literal validation
4. no-duplicate-case - Switch statement validation

Then progress to more complex rules:

• array-callback-return - Requires understanding of array methods
• constructor-super - Requires class hierarchy analysis
• no-fallthrough - Requires control flow analysis

🎯 Overall Assessment

Rating: ⭐⭐⭐⭐ (4/5)

This is excellent scaffolding work that sets up a solid foundation for implementing 30 important ESLint rules. The automated approach is efficient and consistent. The main issue is the registration bug which should be fixed before proceeding with implementation.

Recommendation:

• ✅ Approve the scaffolding approach
• ⚠️ Request fix for the registration bug before merging
• 📋 Keep as DRAFT until rule implementations are complete

📚 References

The PR correctly references:

• ✅ Architecture documentation
• ✅ Rule scaffolding guide
• ✅ ESLint source code
• ✅ Previous PR feat: Automated rule scaffolding tools for ESLint/TypeScript-ESLint migration #14 for tooling

---

Great work on setting up this foundation! The automated scaffolding approach will significantly accelerate the rule implementation process. Once the registration bug is fixed and the rules are implemented, this will be a significant contribution to RSLint's ESLint compatibility.

🤖 Generated with Claude Code

[claude]

PR Review: Scaffolding for 30 ESLint Core Rules

Thank you for this well-organized scaffolding PR! The automated tooling approach is excellent for efficiently setting up the foundation for porting ESLint rules.

Overall Assessment

Strengths:

• Excellent use of automated tooling to generate consistent scaffolding
• Clear PR description with comprehensive documentation
• All code compiles successfully
• Good file organization following established patterns
• Proper fixtures package created to fix test infrastructure

Status: Appropriately marked as DRAFT. The structure is sound and ready for implementation.

---

CRITICAL BUG: Duplicate Rule Registration

Location: internal/config/config.go lines 450-456

The registerAllEslintImportPluginRules() function has a logic error:

The two GlobalRuleRegistry.Register() calls for import/no-self-import and import/no-webpack-loader-syntax are INSIDE the loop. This means they will execute once per iteration, causing duplicate registrations.

Required Fix: Move these two registrations outside the loop.

---

Other Issues to Address

1. Incorrect AST Node Types

All generated rules use ast.KindFunctionDeclaration as a placeholder. During implementation, use correct node types:

• no-debugger → ast.KindDebuggerStatement
• no-const-assign → ast.KindIdentifier or assignment expressions
• no-duplicate-keys → ast.KindObjectLiteralExpression
• for-direction → ast.KindForStatement
• getter-return → ast.KindGetAccessor

2. Missing Options Support

Several rules will need configuration options:

• no-cond-assign: always/except-parens option
• no-constant-condition: checkLoops option
• no-fallthrough: comment pattern options
• no-irregular-whitespace: skip options

3. Placeholder Test Data

Replace generic test placeholders with actual test cases ported from ESLint test suite before final review.

---

Test Coverage

Current State:

• ✅ Test infrastructure properly set up
• ✅ All rules have test file templates
• ❌ No actual test coverage (placeholder tests only)

Recommendations:

1. Port test cases from https://github.com/eslint/eslint/tree/main/tests/lib/rules
2. Add TypeScript-specific edge cases
3. Test autofix functionality where applicable
4. Verify error messages match ESLint exactly

---

Implementation Recommendations

Priority Order (by complexity):

1. no-debugger - Simple, good first implementation
2. no-constant-condition - Medium complexity
3. no-dupe-keys - Medium complexity
4. no-const-assign - Complex, requires scope tracking
5. getter-return - Complex, requires control flow analysis

Before Leaving Draft:

• Fix duplicate registration bug
• Add rule descriptions from ESLint docs
• Document which rules support autofix
• Document which rules require type information
• Document which rules need configuration options
• Replace placeholder tests with real ESLint test cases

Process Suggestions:

• Create GitHub issues for each rule to track progress
• Consider adding CI check to prevent merging unimplemented rules

---

Conclusion

This is excellent scaffolding work that demonstrates good engineering practices. The automated tooling approach will significantly accelerate porting 150+ rules.

Action Required: Fix the critical duplicate registration bug before proceeding.

The foundation is solid - great work! 🚀

---

Review generated with Claude Code

[claude]

Pull Request Review - PR #18: ESLint Core Rules Scaffolding

Overview

This PR successfully scaffolds 30 ESLint core rules from the "Possible Problems" category. The scaffolding approach is well-organized and follows the repository's conventions. Since this is explicitly marked as a DRAFT PR containing only scaffolding, my review focuses on the scaffolding quality, structural issues, and preparation for implementation.

Code Quality & Best Practices

Positive Aspects ✅

1. Consistent Structure: All 30 rules follow identical patterns with proper Go package naming conventions (snake_case)
2. Automated Generation: Leveraging the scaffolding tools from PR feat: Automated rule scaffolding tools for ESLint/TypeScript-ESLint migration #14 ensures consistency
3. Complete Build: All code compiles successfully with no build errors
4. Test Infrastructure: Each rule includes a test file with proper structure
5. Documentation: The PR description is comprehensive and clear about scope and next steps

Issues to Address 🔧

1. Bug in registerAllEslintImportPluginRules() (config.go:450-456)

func registerAllEslintImportPluginRules() {
    for _, rule := range importPlugin.GetAllRules() {
        GlobalRuleRegistry.Register(rule.Name, rule)
        GlobalRuleRegistry.Register("import/no-self-import", no_self_import.NoSelfImportRule)
        GlobalRuleRegistry.Register("import/no-webpack-loader-syntax", no_webpack_loader_syntax.NoWebpackLoaderSyntax)
    }
}

Problem: Lines 453-454 are inside the loop, causing duplicate registrations on every iteration.

Fix: Move these lines outside the loop:

func registerAllEslintImportPluginRules() {
    for _, rule := range importPlugin.GetAllRules() {
        GlobalRuleRegistry.Register(rule.Name, rule)
    }
    GlobalRuleRegistry.Register("import/no-self-import", no_self_import.NoSelfImportRule)
    GlobalRuleRegistry.Register("import/no-webpack-loader-syntax", no_webpack_loader_syntax.NoWebpackLoaderSyntax)
}

2. Incorrect AST Node Listener (All 30 Rules)

All scaffolded rules listen to ast.KindFunctionDeclaration, which is incorrect for most of these rules:

• no-debugger: Should listen to ast.KindDebuggerStatement
• no-duplicate-imports: Should listen to ast.KindImportDeclaration
• no-compare-neg-zero: Should listen to ast.KindBinaryExpression
• getter-return: Should listen to ast.KindGetAccessor or ast.KindMethodDeclaration
• for-direction: Should listen to ast.KindForStatement
• And so on...

Recommendation: Before implementing each rule, update the AST node listeners to match the rule's actual purpose. Reference the ESLint source code for each rule to determine correct node types.

3. Empty Test Cases Are Placeholders Only

The test files contain only valid test cases with placeholder code (const x = 1;). While this is acceptable for draft scaffolding, note that:

• Real test cases should be added during implementation
• Consider porting test cases from ESLint's test suite
• Invalid test cases are essential for verifying rule logic

Security Concerns

Low Risk ✅

This PR poses minimal security concerns:

• Pure scaffolding with no executable logic
• All rules are empty stubs with TODO comments
• No network calls, file operations, or external dependencies introduced
• Follow established patterns from existing rules

Performance Considerations

Current State ✅

Performance impact is negligible:

• Empty rule implementations have minimal overhead
• Registration adds entries to a map (O(1) operation)
• No actual AST traversal logic yet

For Future Implementation ⚠️

When implementing these rules:

1. Efficient AST Traversal: Only register listeners for necessary node types
2. Avoid Redundant Checks: Cache expensive computations when possible
3. Type Checker Usage: Be mindful that type checker operations can be costly
4. Memory Allocation: Reuse objects where possible in hot paths

Test Coverage

Current State 📊

• ✅ All 30 rules have test files
• ✅ Test infrastructure properly set up with fixtures package
• ✅ Tests pass (empty implementations don't report errors)
• ⚠️ Test cases are placeholders only

Recommendations for Implementation Phase

1. Port ESLint Test Cases: Use ESLint's official test suite as reference
2. Cover Edge Cases: Include boundary conditions and error scenarios
3. Test Options: Add test cases for rule options where applicable
4. Autofix Testing: Include autofix test cases for applicable rules
5. Use Test Utilities: Leverage the rule testing framework from PR feat: Comprehensive testing infrastructure for rule development #11

Potential Bugs

Critical Bug 🐛

Location: internal/config/config.go:450-456

• Duplicate rule registration inside loop (detailed in section 1 above)
• This will cause unnecessary overhead and potential race conditions

Medium Priority Issues ⚠️

1. Incorrect Node Listeners: All rules use ast.KindFunctionDeclaration instead of appropriate node types
2. Missing Descriptions: All rules have TODO: Add description comments
3. Missing Error Messages: All error reporting examples use placeholder messages

Architectural Alignment

Follows Repository Conventions ✅

• ✅ Matches directory structure (internal/rules/[rule_name]/)
• ✅ Follows naming conventions (snake_case packages, PascalCase variables)
• ✅ Uses established rule framework from internal/rule/
• ✅ Imports follow standard patterns
• ✅ Test files use fixture utilities correctly

Aligns with Architecture.md ✅

• ✅ Rules implement the rule.Rule interface correctly
• ✅ Uses RuleContext for reporting
• ✅ Follows listener registration pattern
• ✅ Positioned correctly in dependency hierarchy

Recommendations for Next Steps

Before Moving Out of Draft

1. Fix the registration bug in registerAllEslintImportPluginRules()
2. Update AST node listeners for each rule to match their actual purpose
3. Implement rule logic for all 30 rules based on ESLint specifications
4. Port comprehensive test cases from ESLint test suite
5. Add rule descriptions based on ESLint documentation
6. Implement autofixes where ESLint provides them (12 of these rules have autofixes)

Implementation Priority Suggestions

Consider implementing in this order:

1. Simple rules first: no-debugger, no-compare-neg-zero, no-duplicate-case
2. Medium complexity: no-const-assign, no-dupe-keys, getter-return
3. Complex rules: no-fallthrough, array-callback-return, constructor-super

Testing Strategy

1. Create a tracking issue for each rule implementation
2. Implement 5-10 rules at a time in separate commits
3. Ensure all tests pass before moving to the next batch
4. Run integration tests against real codebases periodically

Summary

Strengths:

• Well-organized scaffolding with consistent structure
• Successful automation using code generation tools
• Comprehensive PR description and documentation
• Clean build with no compilation errors

Issues:

• One critical bug in import rule registration (easy fix)
• Incorrect AST node listeners (expected for scaffolding)
• Placeholder test cases (expected for draft)

Verdict: This is excellent scaffolding work that provides a solid foundation for implementation. The critical bug should be fixed before merging, but otherwise the structure is sound. Ready to proceed with actual rule implementations once the bug is addressed.

---

Great work on the scaffolding automation! This will significantly accelerate the rule porting effort. 🎉

Review generated by Claude Code