Fix MatrixDataSource failing with ClassConstructor#4838
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When a test class uses [ClassConstructor<T>] for DI and has [MatrixDataSource] tests, the matrix expansion fails with IndexOutOfRangeException because the early instance creation bypasses ClassConstructorHelper and calls InstanceFactory directly, which tries to index into an empty args array. Fixes both engine and source generator: - Engine: CreateInstanceForMethodDataSources now checks ClassConstructor first - Engine: Consolidated duplicated instance creation in BuildTestsFromMetadataAsync - Source gen: InstanceFactoryGenerator.HasClassConstructorAttribute now checks assembly-level [assembly: ClassConstructor<T>] in addition to class attributes - Source gen: All inline InstanceFactory paths in TestMetadataGenerator now guard against ClassConstructor, emitting the throw-stub instead of constructor code Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Code reviewNo issues found. Checked for bugs and CLAUDE.md compliance. This is a well-structured fix that properly addresses the dual-mode compatibility requirements. The changes correctly implement ClassConstructor detection in both the source generator (with throw-stubs) and the engine (with proper fallback logic), ensuring that |
This was referenced Feb 17, 2026
This was referenced Feb 18, 2026
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Summary
IndexOutOfRangeExceptionwhen a test class uses[ClassConstructor<T>]for DI and has[MatrixDataSource]tests ([BUG] Test Classes With Injected Dependencies Cause Matrix Expansion To Fail #4836)ClassConstructorHelperbefore falling back toInstanceFactory[assembly: ClassConstructor<T>]and guards all inlineInstanceFactorycode paths with the ClassConstructor throw-stubTest plan
TUnit.Enginebuilds successfully (0 errors, 0 warnings)TUnit.Core.SourceGeneratorbuilds successfully (0 errors, 0 warnings).received.txtchanges)[ClassConstructor<T>]+[MatrixDataSource]test method🤖 Generated with Claude Code