[thomhurst]

Fixes #7092

Summary

tests/TUnit.UnitTests fails 4 tests on net10.0 with --reflection on main; they pass in source-gen mode. Each failure is a real reflection-mode bug, not a test that relies on source-gen behaviour. I found two more mode differences while reproducing them, and this PR fixes those too.

Root causes and fixes

Test / symptom	Root cause	Fix
EmptyStaticDataSource_ShouldYieldOneEmptyResult: No members to generate were provided for TestParameters	The reflection path of MethodDataSourceAttribute.GetDataRowsAsync threw when MembersToGenerate was empty. It is always empty for a parameterless test method.	Treat empty MembersToGenerate as valid.
TestWithAsyncValueTaskDataSource: ValueTask<...> cannot be converted to Int32	The reflection path handled Task<T>, IAsyncEnumerable<T> and IEnumerable, but not ValueTask<T>, so the result was passed to the test without being awaited.	Convert ValueTask<T> to Task<T> with AsTask (the MethodInfo is cached per type) and reuse the Task branch.
GenericTestWithData<Int32>: String cannot be converted to Int32	For each [GenerateGenericTest] type, the reflection collector closed the method and attached every [Arguments] row. The generator pairs each row with the instantiation inferred from it, so reflection made 4 tests where source-gen makes 2.	ResolveMethodInstantiations uses the generator's algorithm. Each [Arguments] row closes the method over the types inferred from its own values and runs only there. Each [GenerateGenericTest] type that no row inferred runs with every row. For example, [GenerateGenericTest(typeof(long))] [Arguments(1)] [Arguments(2L)] gives <int>(1) and <long>(2) in both modes.
InitializeEntity (+ dependent CanSetCustomerName skipped): Late bound operations cannot be performed on types or methods for which ContainsGenericParameters is true	[Before(Class)] on RepositoryTestBase<T> was invoked through the open-generic MethodInfo. The generated hook body binds the method to the closed base type of context.ClassType.	Hook delegates bind open-generic hook methods to the closed type in the class's inheritance chain, using MethodBase.GetMethodFromHandle, with a cache. Static hooks use the class from the hook context; instance hooks use the instance type. A static hook found on a constructed base (Base<int> reached from a derived class) is registered against the open definition, as source-gen does, so it runs once and not twice.
Reflection discovery found no tests and crashed with SemaphoreSlim maxCount 0 when the checkout path contained ref or runtimes (e.g. ...\reflection-unittests\)	ShouldScanAssembly used location.Contains("ref"). With zero assemblies, new SemaphoreSlim(0, 0) throws.	Match whole directory names. Also clamp the concurrency to at least 1.
EmptyStaticDataSource_ShouldYieldOneEmptyResult did not exist in source-gen mode	An empty [MethodDataSource] without SkipIfEmpty yields one empty row in reflection mode, so the test runs once with no arguments (#2862). The source-generated Factory path yielded no rows, so the test was never created.	Owner decision in #7092: both modes run the test once with no arguments. GetDataRowsAsync now yields one empty row after an empty Factory enumeration unless SkipIfEmpty is set. This is a TUnit.Core change, so generator output is unchanged.
Source-gen: [MethodDataSource(..., SkipIfEmpty = true)] with an empty source made the test disappear instead of being reported as skipped	The generator's MethodDataSourceAttribute emission dropped SkipIfEmpty.	Emit SkipIfEmpty = true, the same way DeferEnumeration is emitted.

AOT and trimming: every change except the generator change is in reflection-only paths. The new reflection is annotated or suppressed in the same way as the code around it. TUnit.Core and TUnit.Engine build with the trim analyzers and produce no warnings. I could not run an AOT publish locally because this machine has no native linker; CI covers AOT through TUnit.Engine.Tests.

Tests

New fixtures in tests/TUnit.TestProject/Bugs/_7092 ([EngineTest(ExpectedResult.Pass)]), one per shape. tests/TUnit.Engine.Tests/Issue7092Tests.cs runs them in both Reflection and AOT modes.

• New generator snapshot Tests7092 checks that SkipIfEmpty = true is emitted.
• New ReflectionAssemblyLocationFilterTests in TUnit.UnitTests covers the path filter.

Local results (Windows, net10.0):

• TUnit.UnitTests, source-gen: 538 total, 0 failed (537 before the empty-source change, because EmptyStaticDataSource_ShouldYieldOneEmptyResult was missing).
• TUnit.UnitTests, --reflection: 538 total, 0 failed. It was 532 total with 4 failed on main.
• The Bugs._7092 fixtures, run directly in both modes: all pass. The SkipIfEmpty fixture is reported as 1 skipped in both modes.
• TestProject [EngineTest=Pass] tests, source-gen mode: 5968 total, 0 failed. Reflection mode: 5955 total, 0 failed.
• TUnit.Engine.Tests Issue7092Tests: Reflection mode passes. The AOT cases skip locally.
• Related TUnit.Engine.Tests classes all pass in Reflection mode: hook classes, DataSourceCountTests, DataSourceExceptionPropagationTests, GenericMethodWithDataSourceTests, DeferEnumerationTests, SkipTests and others.
• TUnit.Core.SourceGenerator.Tests: all 186 pass on net10.0. The new snapshot also passes on net8.0 and net472.

Behaviour change for source-gen users

A test with an empty [MethodDataSource] and no SkipIfEmpty now runs once with no arguments in source-gen mode, as it already did in reflection mode. Before this change the test was not created at all. If the test method has parameters, that run fails with an argument-count error, which is the same result reflection mode already gives. Set SkipIfEmpty = true to report the test as skipped instead.

Review follow-ups

• Generic-base class hooks ran twice in reflection mode: fixed, and the fixture now asserts an exact run count.
• [GenerateGenericTest] row pairing now matches source-gen output, including rows such as an int literal on a <long> instantiation. The compatibility filter is gone.
• Reflection also infers instantiations from typed data sources (DataSourceGeneratorAttribute<T>, AsyncDataSourceGeneratorAttribute<T>) and from IInfersType<T> parameter attributes such as Matrix<T>, as source-gen does. A [GenerateGenericTest] type that any of these already produced is not repeated. So is inference from a [MethodDataSource] returning IEnumerable<Func<(...)>>. Tuple types are flattened through TRest, so eight or more elements infer correctly. Rows whose inferred types violate constraints are skipped, as the generator does today; fix(engine): substitute class type arguments and array element types in build-time constraint checks #7102 changes the generator to report them as failures, and reflection will need the same change once it merges.
• Rows whose values suggest conflicting types ([Arguments("x", 1)] on Test<T>(T, T)) take the last type in both modes. That is existing source-gen behaviour, so I left it unchanged.
• Known source-gen gaps, older than this PR and left for follow-up: when several rows infer the same type, only the first runs ([Arguments(1)] [Arguments(2)] Test<T>(T) gives only Test<int>(1)). params T[] with [GenerateGenericTest] does not compile (CS0246).

Summary by CodeRabbit

• Bug Fixes
  • Empty method data sources now run parameterless tests once by default, or are skipped when SkipIfEmpty is enabled.
  • ValueTask-based data sources are awaited correctly.
  • Generic tests now match data rows and typed data sources to inferred types, while retaining rows for explicitly generated types.
  • Hooks on generic base classes run for the appropriate closed type without duplicate static registration.
  • Assembly discovery more accurately excludes framework directories, avoiding false matches from partial directory names.

[chatgpt-codex-connector]

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📝 Walkthrough

Reflection discovery now handles empty and asynchronous method data sources, infers generic test types from data sources and argument rows, binds generic base hooks to closed types, and filters assembly paths by directory name. Generated method data-source attributes retain SkipIfEmpty = true.

Changes: Reflection and Data-Source Discovery

Layer / File(s)	Summary
Method data-source handling src/TUnit.Core/Attributes/TestData/MethodDataSourceAttribute.cs, src/TUnit.Core.SourceGenerator/Generators/TestMetadataGenerator.cs, tests/TUnit.Core.SourceGenerator.Tests/Bugs/7092/*, tests/TUnit.Core.SourceGenerator.Tests/Tests7092.Test.verified.txt, tests/TUnit.TestProject/Bugs/_7092/SkipIfEmptyMethodDataSourceTests.cs, tests/TUnit.TestProject/Bugs/_7092/EmptyMethodDataSourceTests.cs, tests/TUnit.TestProject/Bugs/_7092/ReflectionModeParityTests.cs, tests/TUnit.Engine.Tests/Issue7092Tests.cs, tests/TUnit.UnitTests/EmptyDataSourceTests.cs	Reflection method data sources support parameterless methods, generic ValueTask results, and an empty argument row unless SkipIfEmpty is true. Generated attributes retain SkipIfEmpty = true. Regression tests cover empty sources, asynchronous sources, and skip behavior.
Generic argument-row inference src/TUnit.Engine/Discovery/ReflectionTestDataCollector.cs, tests/TUnit.TestProject/Bugs/_7092/ReflectionModeParityTests.cs, tests/TUnit.TestProject/Bugs/_7092/GenerateGenericTest*Tests.cs, tests/TUnit.Engine.Tests/Issue7092Tests.cs	Reflection discovery infers method type arguments from argument rows, typed data sources, method data sources, and parameter attributes. It associates applicable sources with each instantiation and avoids duplicate inferred types. Tests cover type inference and row pairing.
Generic base hook binding src/TUnit.Engine/Discovery/ReflectionHookDiscoveryService.cs, tests/TUnit.TestProject/Bugs/_7092/ReflectionModeParityTests.cs, tests/TUnit.Engine.Tests/Issue7092Tests.cs	Static hooks on constructed generic bases register against open definitions. Hook delegates resolve open generic methods against matching closed types before invocation.
Assembly location filtering src/TUnit.Engine/Discovery/ReflectionTestDataCollector.cs, tests/TUnit.UnitTests/ReflectionAssemblyLocationFilterTests.cs	Assembly filtering checks exact ancestor-directory names, ignoring case, instead of matching directory-name substrings. Assembly-scan concurrency is clamped to at least one. Tests cover matching and non-matching directory names.

Priority: ➖ Normal

Estimated code review effort: 4 (Complex) | ~45 minutes

Change: Bug fix · Severity of issue fixed: Medium

Sequence Diagram(s)

sequenceDiagram
  participant ReflectionTestDataCollector
  participant GenericInference
  participant DataSources
  participant TestMetadata
  ReflectionTestDataCollector->>GenericInference: resolve generic method instantiations
  GenericInference->>DataSources: infer types and applicable rows
  DataSources-->>GenericInference: type arguments and rows
  GenericInference-->>ReflectionTestDataCollector: concrete methods and source associations
  ReflectionTestDataCollector->>TestMetadata: build metadata with applicable data sources

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Merge Risk: 🔵 Low · up to 5a2a1

Unusual argument rows or same-named provider methods may cause incorrect generic test instantiation or failures. These bounded cases warrant owner awareness, but do not appear to block merging.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 35.71% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 70 functions across 15 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main objective: aligning reflection-mode data sources and hooks with source-generated behavior. It is specific, relevant, and suitable for repository hist…
Linked Issues check		Issue #7092 is the active direct target. The reviewed changes address its coding requirements for parameterless MethodDataSource, ValueTask<T> data sources, generic argument-row pairing and infere…
Out of Scope Changes check		The production changes remain connected to issue #7092. The core changes implement data-source parity, the engine changes implement reflection discovery and generic and hook behavior, and the generato…

Full details: Title check

Explanation

The title clearly and concisely describes the main objective: aligning reflection-mode data sources and hooks with source-generated behavior. It is specific, relevant, and suitable for repository history.

Full details: Linked Issues check

Explanation

Issue #7092 is the active direct target. The reviewed changes address its coding requirements for parameterless MethodDataSource, ValueTask<T> data sources, generic argument-row pairing and inference, open-generic hooks, assembly-path filtering, discovery concurrency, and generated SkipIfEmpty. The changes also align empty-source behavior across reflection and source generation. Focused regression tests cover these behaviors, including tuple and typed-source inference. The supplied results report passing source-generation, reflection, and focused engine tests.

Full details: Out of Scope Changes check

Explanation

The production changes remain connected to issue #7092. The core changes implement data-source parity, the engine changes implement reflection discovery and generic and hook behavior, and the generator change preserves SkipIfEmpty. The added fixtures, snapshot, and unit tests verify these objectives. No unrelated change is established by the available evidence.

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[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: abfc8312bc

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[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; no new blocking issue was found.

Summary

Aligns reflection-mode data sources and generic hooks with source-generated tests.

• Generic test rows run with the types their data sources infer.
• Method data sources handle empty rows, parameterless tests, and ValueTask results consistently.
• Hooks on generic base classes run on the matching closed type.
• Reflection discovery filters framework paths by whole directory name.

No new actionable issues found. All seven supplied previous threads were unnumbered; their reported fixes are present.

thomhurst explicitly left constraint-error reporting, older source-gen repeated-row behavior, and params T[] compilation for follow-up. thomhurst also retained last-value inference for conflicting types and declined to copy source-gen's mistyped cross-row behavior on generic classes.

Tests were inspected, not run.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[Generic test method] --> B[Infer types from sources]
  B --> C[Close method and select its source rows]
  A --> D[Explicit generated types]
  D --> E{Already inferred?}
  E -->|Yes| F[Skip duplicate instantiation]
  E -->|No| G[Run all method sources]
  C --> H[Build test metadata]
  G --> H

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Actionable comments posted: 2

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Review comments at @src/TUnit.Engine/Discovery/ReflectionAttributeExtractor.cs:
- Around line 281-284: In ReflectionAttributeExtractor, validate supplied values
for T[] parameters against each closed array element type before returning on a
values.Length and closedParameters.Length mismatch; discard incompatible rows
when any compatible row exists, while preserving the fallback that retains all
rows when none are compatible. Add a regression with mixed array-bound rows and
verify reflection and source-generated modes produce the same result.

Review comments at
@src/TUnit.Engine/Discovery/ReflectionHookDiscoveryService.cs:
- Around line 995-997: Update hook discovery around CloseOpenGenericHookMethod
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📒 Files selected for processing: 11

• src/TUnit.Core.SourceGenerator/Generators/TestMetadataGenerator.cs
• src/TUnit.Core/Attributes/TestData/MethodDataSourceAttribute.cs
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• src/TUnit.Engine/Discovery/ReflectionHookDiscoveryService.cs
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• tests/TUnit.Core.SourceGenerator.Tests/Bugs/7092/Tests7092.cs
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• tests/TUnit.TestProject/Bugs/_7092/ReflectionModeParityTests.cs
• tests/TUnit.TestProject/Bugs/_7092/SkipIfEmptyMethodDataSourceTests.cs
• tests/TUnit.UnitTests/ReflectionAssemblyLocationFilterTests.cs

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[github-actions]

Review of #7094

I read the diff but did not build the PR or run any tests. Each fix targets a root cause, and the PR description lines it up with the failing tests. The pieces I looked at were the SkipIfEmpty generator change, the ValueTask<T> handling, the generic-argument filtering, the open-generic hook binding, and the assembly-location matching.

I found nothing blocking. These are suggestions:

1. Generic-argument filtering (ReflectionAttributeExtractor.FilterArgumentsForClosedGenericMethod). It approximates the generator's type inference with IsInstanceOfType on the boxed value. This could diverge from the generator in edge cases, for example Test<long> with [Arguments(5)], where the generator infers int. The fallback of keeping all rows when none fit is a sensible safety net. Consider adding a reflection-mode test for a mixed-type case, such as int, string and a null row. That would pin the parity with the source-gen output.

2. Open-generic hook binding. The change is correct. CloseOpenGenericHookMethod caches per (method, classType), so the lookup cost is paid once. MethodBase.GetMethodFromHandle is AOT-safe. Both hook delegate paths use the same helper, which is good. The helper falls back to the original method when no closed match exists, so the original error still shows. A comment saying that this fallback is intentional would help.

3. ValueTask<T> conversion. The AsTask lookup is cached per type, which is fine. Because the reflection path calls Invoke, a TargetInvocationException could wrap any exception the source throws. Check that the surrounding code already unwraps it, as it does for the Task branch.

4. Assembly-location check. Matching whole directory names is clearly better than the old Contains("ref") substring test. The test coverage for the new method covers this.

5. SkipIfEmpty in the generator. Emitting it keeps source-gen consistent with reflection mode. The new snapshot test covers it.

The Math.Max(1, …) guard on the concurrency count is a good defensive fix.

Overall the PR looks good.

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Actionable comments posted: 1

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Inline comments:
Review comments at @src/TUnit.Engine/Discovery/ReflectionTestDataCollector.cs:
- Around line 1457-1467: Update generic type inference in both the reflection
collector and source generator to reject conflicting inferred types for the same
generic parameter: compare each new inference with the existing one and return
null on a mismatch; retain the existing assignment behavior when they match or
no prior inference exists. Locate the reflection logic in the loop using
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Inline comments:
Review comments at
@src/TUnit.Core/Attributes/TestData/MethodDataSourceAttribute.cs:
- Around line 160-172: Update the PR description to state that an empty
source-generated MethodDataSource runs the test once with no arguments when
SkipIfEmpty is false, matching reflection mode. Preserve the implementation and
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