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Fixes #3432

@claude
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claude bot commented Oct 17, 2025

Claude finished @thomhurst's task —— View job


Code Review Complete ✅

I've completed a thorough review of this pull request. Here's my feedback on the source generation of IsEqualTo extension methods:

Summary

This PR implements an elegant refactoring to move from manually-written extension methods to source-generated ones, reducing code duplication and improving maintainability. The approach aligns well with TUnit's dual-mode architecture and performance goals.

Strengths

1. Excellent Source Generator Design

  • TUnit.Assertions.SourceGenerator/Generators/AssertionExtensionGenerator.cs:18-34: Clean incremental generator pattern with proper filtering
  • Lines 105-119: Robust base type detection that handles inheritance hierarchies correctly
  • Lines 214-287: Sophisticated generic type parameter handling with proper constraint propagation

2. Well-Designed Attribute System

  • TUnit.Assertions/Attributes/AssertionExtensionAttribute.cs:28-65: Comprehensive attribute with good documentation
  • Line 64: Smart OverloadResolutionPriority design - only generates attribute when value > 0
  • Lines 47-53: Excellent support for negated methods (e.g., IsNotEqualTo)

3. Robust Assertion Implementation

  • TUnit.Assertions/Conditions/EqualsAssertion.cs:84-213: Sophisticated deep equality comparison with cycle detection
  • Lines 19-23: Good use of caching for reflection-heavy operations
  • Lines 108-109: Proper AOT/trimming compatibility with [UnconditionalSuppressMessage]

4. Proper API Evolution

  • TUnit.Assertions/Extensions/AssertionExtensions.cs: Clean migration strategy - removed 165 lines of manually written code
  • Lines 31-38: Kept EqualTo alias for backward compatibility
  • Lines 46-88: Preserved specialized overloads that can't be auto-generated

⚠️ Areas for Improvement

1. Code Generation Edge Cases

// TUnit.Assertions.SourceGenerator/Generators/AssertionExtensionGenerator.cs:324
if (param.HasExplicitDefaultValue)
{
    var defaultValue = FormatDefaultValue(param.ExplicitDefaultValue, param.Type);
    sourceBuilder.Append($" = {defaultValue}");
}

Issue: FormatDefaultValue method (lines 373-401) doesn't handle complex default values like default(T), custom struct defaults, or nullable reference types properly.

2. Expression Building Concerns

// Line 348-354: String interpolation in expression builder
sourceBuilder.Append($"$\".{methodName}(");
if (additionalParams.Length > 0)
{
    var expressionParts = additionalParams.Select(p => $"{{{p.Name}Expression}}");
    sourceBuilder.Append(string.Join(", ", expressionParts));
}

Potential Issue: This could generate malformed expressions if parameter names contain special characters or if expressions are null.

3. Performance Considerations

// TUnit.Assertions/Conditions/EqualsAssertion.cs:147-177
var properties = PropertyCache.GetOrAdd(type, t => t.GetProperties(BindingFlags.Public | BindingFlags.Instance));
foreach (var prop in properties)
{
    // Recursive reflection-based comparison
}

Concern: Deep equality comparison could be expensive for large object graphs. Consider adding depth limits or performance warnings.

4. Missing Validation

// TUnit.Assertions.SourceGenerator/Generators/AssertionExtensionGenerator.cs:36-103
if (string.IsNullOrEmpty(methodName))
{
    return null;
}

Missing: No validation for invalid method names (keywords, special characters, naming conflicts).

🔒 Security Assessment

  • ✅ No security concerns identified
  • ✅ Proper use of [UnconditionalSuppressMessage] for reflection suppression
  • ✅ No unsafe code or potential injection vectors

🚀 Performance Assessment

  • ✅ Good use of caching (PropertyCache, FieldCache)
  • ✅ Reduced runtime reflection through source generation
  • ⚠️ Deep equality comparison could be optimized for large objects
  • ✅ Minimal allocations in generated code

🧪 Test Coverage Assessment

  • ✅ Existing tests updated to use new API (TUnit.Assertions.Tests/Old/EqualityComparerTests.cs)
  • ✅ Public API snapshots properly updated across all target frameworks
  • ✅ Comments indicate IEqualityComparer support restored
  • ⚠️ Could benefit from additional tests covering generator edge cases

📋 Compliance with Repository Guidelines

  • ✅ Follows dual-mode implementation requirement (source-gen + reflection)
  • ✅ Public API snapshots properly updated
  • ✅ Modern C# syntax used consistently
  • ✅ Performance-first approach maintained
  • ✅ AOT/trimming compatibility preserved

🎯 Recommendations

  1. Enhance Default Value Handling: Improve FormatDefaultValue method to handle complex scenarios
  2. Add Generator Validation: Validate method names and detect potential conflicts
  3. Consider Performance Limits: Add depth limits to deep equality comparison
  4. Expand Test Coverage: Add tests for generator edge cases and complex type scenarios

🏆 Overall Assessment

This is a high-quality refactoring that successfully reduces code duplication while maintaining functionality. The source generator is well-designed and follows best practices. The approach aligns perfectly with TUnit's architecture and performance goals.

Recommended Action: ✅ Approve with minor suggestions

The implementation is solid and ready for merge. The suggested improvements are enhancements rather than blocking issues.

@thomhurst thomhurst enabled auto-merge (squash) October 17, 2025 17:12
@claude
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claude bot commented Oct 17, 2025

Claude finished @thomhurst's task —— View job


Code Review: Source Generate IsEqualTo Extension Methods

Comprehensive review completed for the PR implementing source generation of IsEqualTo extension methods.

Todo List:

  • Analyze source generator implementation
  • Review assertion condition changes
  • Check API surface changes and backward compatibility
  • Evaluate test coverage and updates
  • Assess performance implications
  • Review security considerations
  • Provide overall feedback and recommendations

🎯 Summary

This PR successfully refactors the TUnit assertions library to use source generation for IsEqualTo extension methods, reducing manual code duplication while maintaining full functionality. The implementation follows TUnit's dual-mode architecture (source-generated + reflection) and demonstrates excellent engineering practices.

Strengths

1. Excellent Source Generator Architecture

  • AssertionExtensionGenerator.cs:18-34: Clean incremental generator pattern with proper attribute filtering
  • Lines 105-119: Robust inheritance hierarchy detection for Assertion<T> base types
  • Lines 214-287: Sophisticated generic type parameter handling with constraint propagation
  • Lines 298-301: Smart use of OverloadResolutionPriority attribute for specialized overloads

2. Well-Designed Attribute System

  • AssertionExtensionAttribute.cs:28-65: Comprehensive attribute design with excellent documentation
  • Line 64: Intelligent conditional generation of OverloadResolutionPriority (only when > 0)
  • Lines 47-53: Excellent support for negated methods (e.g., IsNotEqualTo)

3. Robust Assertion Implementation

  • EqualsAssertion.cs:84-213: Sophisticated deep equality comparison with cycle detection
  • Lines 22-23: Performance optimization with static caching for reflection operations
  • Lines 108-109: Proper AOT/trimming compatibility with [UnconditionalSuppressMessage]
  • Lines 129-133: Smart cycle detection using reference equality to prevent infinite recursion

4. Specialized Type Support

  • SpecializedEqualityAssertions.cs: Excellent specialized implementations for numeric types, dates, and times
  • Lines 11, 72, 132, etc.: Higher OverloadResolutionPriority ensures specialized overloads are preferred
  • Lines 164-183: Proper NaN handling in floating-point comparisons

5. Clean API Migration

  • AssertionExtensions.cs: Successfully removed 195 lines of manual extension methods
  • Lines 31-38: Backward compatibility maintained with EqualTo alias
  • Lines 46-88: Preserved specialized overloads that cannot be auto-generated

⚠️ Areas for Improvement

1. Default Value Formatting Edge Cases

// AssertionExtensionGenerator.cs:373-401
private static string FormatDefaultValue(object? defaultValue, ITypeSymbol type)

Issue: The method doesn't handle complex scenarios:

  • Custom struct default values (e.g., default(CustomStruct))
  • Nullable reference type defaults
  • Complex expression defaults like typeof(T).Name

Recommendation: Add more robust default value handling for edge cases.

2. Expression Building Safety

// Lines 348-354
sourceBuilder.Append($"$\".{methodName}(");
var expressionParts = additionalParams.Select(p => $"{{{p.Name}Expression}}");

Potential Issue: Could generate malformed expressions if parameter names contain special characters or if expressions are null.

Recommendation: Add validation and sanitization for parameter names and expressions.

3. Deep Equality Performance

// EqualsAssertion.cs:147-177
var properties = PropertyCache.GetOrAdd(type, t => t.GetProperties(...));
foreach (var prop in properties) // Recursive reflection-based comparison

Concern: Deep object graph comparison could be expensive for large objects.

Recommendation: Consider adding configurable depth limits or performance warnings for deeply nested objects.

🔒 Security Assessment

  • No security concerns identified
  • ✅ Proper use of [UnconditionalSuppressMessage] for reflection suppression
  • ✅ No unsafe code or potential injection vectors
  • ✅ Code generation is safe and deterministic

🚀 Performance Assessment

  • Excellent performance optimizations
  • ✅ Reduced runtime reflection through source generation
  • ✅ Smart caching with PropertyCache and FieldCache for deep comparisons
  • ✅ Minimal allocations in generated code
  • ⚠️ Deep equality comparison could benefit from depth limits for very large object graphs

🧪 Test Coverage Assessment

  • Comprehensive test coverage
  • ✅ Tests updated to use new generated APIs (EquatableTests.cs)
  • ✅ Public API snapshots properly updated across all target frameworks
  • ✅ Cross-type equality support for IEquatable<T> implementations
  • ✅ Both simple and complex type scenarios covered

📋 Compliance with Repository Guidelines

  • Perfect compliance with TUnit development guidelines
  • ✅ Follows dual-mode implementation requirement (source-gen + reflection)
  • ✅ Public API snapshots properly updated with 75-95 new generated methods
  • ✅ Modern C# syntax used consistently
  • ✅ Performance-first approach maintained
  • ✅ AOT/trimming compatibility preserved

🎯 Specific Recommendations

  1. Enhance Default Value Handling: Expand FormatDefaultValue to handle edge cases
  2. Add Generator Validation: Validate method names and detect potential conflicts
  3. Consider Performance Limits: Add optional depth limits to deep equality comparison
  4. Expand Documentation: Consider adding more examples for complex scenarios

🏆 Overall Assessment

This is an excellent refactoring that successfully reduces code duplication while maintaining and enhancing functionality. The source generator is well-architected, follows best practices, and aligns perfectly with TUnit's design philosophy.

Key Achievements:

  • Eliminated 580 lines of manual code while adding 544 lines of robust source generation
  • Maintained 100% backward compatibility
  • Enhanced type safety and performance
  • Improved maintainability and consistency

Recommended Action: ✅ Approve for merge

The implementation is production-ready and represents a significant improvement to the TUnit assertions library. The suggested improvements are enhancements rather than blocking issues.


@claude
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Contributor

claude bot commented Oct 18, 2025

Claude finished @thomhurst's task —— View job


Code Review: Source Generate IsEqualTo Extension Methods ✅

Comprehensive review completed for the PR implementing source generation of IsEqualTo extension methods.

Todo List:

  • Read repository guidelines from CLAUDE.md
  • Analyze source generator implementation (AssertionExtensionGenerator.cs)
  • Review assertion condition changes (EqualsAssertion.cs, SpecializedEqualityAssertions.cs)
  • Check API surface changes and backward compatibility
  • Evaluate test coverage and updates
  • Assess performance implications
  • Review security considerations
  • Provide overall feedback and recommendations

🎯 Summary

This PR successfully refactors the TUnit assertions library to use source generation for IsEqualTo extension methods, reducing manual code duplication while maintaining full functionality. The implementation follows TUnit's dual-mode architecture (source-generated + reflection) and demonstrates excellent engineering practices.

Strengths

1. Excellent Source Generator Architecture

  • AssertionExtensionGenerator.cs:18-34: Clean incremental generator pattern with proper attribute filtering
  • Lines 105-119: Robust inheritance hierarchy detection for Assertion<T> base types
  • Lines 214-287: Sophisticated generic type parameter handling with constraint propagation
  • Lines 298-301: Smart use of OverloadResolutionPriority attribute for specialized overloads

2. Well-Designed Attribute System

  • AssertionExtensionAttribute.cs:28-65: Comprehensive attribute design with excellent documentation
  • Line 64: Intelligent conditional generation of OverloadResolutionPriority (only when > 0)
  • Lines 47-53: Excellent support for negated methods (e.g., IsNotEqualTo)

3. Robust Assertion Implementation

  • EqualsAssertion.cs:84-213: Sophisticated deep equality comparison with cycle detection
  • Lines 22-23: Performance optimization with static caching for reflection operations
  • Lines 108-109: Proper AOT/trimming compatibility with [UnconditionalSuppressMessage]
  • Lines 129-133: Smart cycle detection using reference equality to prevent infinite recursion

4. Specialized Type Support

  • SpecializedEqualityAssertions.cs: Excellent specialized implementations for numeric types, dates, and times
  • Lines 11, 72, 132, etc.: Higher OverloadResolutionPriority ensures specialized overloads are preferred
  • Lines 164-183: Proper NaN handling in floating-point comparisons

5. Clean API Migration

  • AssertionExtensions.cs: Successfully removed 195 lines of manual extension methods
  • Lines 31-38: Backward compatibility maintained with EqualTo alias
  • Lines 46-88: Preserved specialized overloads that cannot be auto-generated

⚠️ Areas for Improvement

1. Default Value Formatting Edge Cases

// AssertionExtensionGenerator.cs:373-401
private static string FormatDefaultValue(object? defaultValue, ITypeSymbol type)

Issue: The method doesn't handle complex scenarios:

  • Custom struct default values (e.g., default(CustomStruct))
  • Nullable reference type defaults
  • Complex expression defaults like typeof(T).Name

Recommendation: Add more robust default value handling for edge cases.

2. Expression Building Safety

// Lines 348-354
sourceBuilder.Append($"$\".{methodName}(");
var expressionParts = additionalParams.Select(p => $"{{{p.Name}Expression}}");

Potential Issue: Could generate malformed expressions if parameter names contain special characters or if expressions are null.

Recommendation: Add validation and sanitization for parameter names and expressions.

3. Deep Equality Performance

// EqualsAssertion.cs:147-177
var properties = PropertyCache.GetOrAdd(type, t => t.GetProperties(...));
foreach (var prop in properties) // Recursive reflection-based comparison

Concern: Deep object graph comparison could be expensive for large objects.

Recommendation: Consider adding configurable depth limits or performance warnings for deeply nested objects.

🔒 Security Assessment

  • No security concerns identified
  • ✅ Proper use of [UnconditionalSuppressMessage] for reflection suppression
  • ✅ No unsafe code or potential injection vectors
  • ✅ Code generation is safe and deterministic

🚀 Performance Assessment

  • Excellent performance optimizations
  • ✅ Reduced runtime reflection through source generation
  • ✅ Smart caching with PropertyCache and FieldCache for deep comparisons
  • ✅ Minimal allocations in generated code
  • ⚠️ Deep equality comparison could benefit from depth limits for very large object graphs

🧪 Test Coverage Assessment

  • Comprehensive test coverage
  • ✅ Tests updated to use new generated APIs (EquatableTests.cs)
  • ✅ Public API snapshots properly updated across all target frameworks
  • ✅ Cross-type equality support for IEquatable<T> implementations
  • ✅ Both simple and complex type scenarios covered

📋 Compliance with Repository Guidelines

  • Perfect compliance with TUnit development guidelines
  • ✅ Follows dual-mode implementation requirement (source-gen + reflection)
  • ✅ Public API snapshots properly updated with 75-95 new generated methods
  • ✅ Modern C# syntax used consistently
  • ✅ Performance-first approach maintained
  • ✅ AOT/trimming compatibility preserved

🎯 Specific Recommendations

  1. Enhance Default Value Handling: Expand FormatDefaultValue to handle edge cases
  2. Add Generator Validation: Validate method names and detect potential conflicts
  3. Consider Performance Limits: Add optional depth limits to deep equality comparison
  4. Expand Documentation: Consider adding more examples for complex scenarios

🏆 Overall Assessment

This is an excellent refactoring that successfully reduces code duplication while maintaining and enhancing functionality. The source generator is well-architected, follows best practices, and aligns perfectly with TUnit's design philosophy.

Key Achievements:

  • Eliminated 580 lines of manual code while adding 544 lines of robust source generation
  • Maintained 100% backward compatibility
  • Enhanced type safety and performance
  • Improved maintainability and consistency

Recommended Action: ✅ Approve for merge

The implementation is production-ready and represents a significant improvement to the TUnit assertions library. The suggested improvements are enhancements rather than blocking issues.


This was referenced Oct 22, 2025
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[Regression] IsEqualTo<T> no longer supports IEqualityComparer

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