Add analyzer "Lookup Must Return Nullable Type"#9552
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Pull request overview
Adds a new Roslyn analyzer to enforce that members annotated with Hot Chocolate’s [Lookup] attribute return nullable types, aligning schema nullability with lookup semantics (lookups can legitimately not find a result).
Changes:
- Introduce analyzer
HC0113(“Lookup Must Return Nullable Type”) for methods and properties annotated with[Lookup]. - Add a code fix provider that offers to make the return type nullable.
- Add analyzer tests and snapshot baselines; wire the analyzer into the test harness.
Reviewed changes
Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| src/HotChocolate/Core/src/Types.Analyzers/LookupReturnsNonNullableTypeAnalyzer.cs | New analyzer that reports HC0113 when [Lookup] return types are non-nullable (incl. Task/ValueTask unwrapping). |
| src/HotChocolate/Core/src/Types.Analyzers/LookupReturnsNonNullableTypeCodeFixProvider.cs | New code fix provider to make lookup return types nullable. |
| src/HotChocolate/Core/src/Types.Analyzers/Errors.cs | Registers the new diagnostic descriptor HC0113. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/TestHelper.cs | Adds the new analyzer to the test analyzer set. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/LookupReturnsNonNullableTypeAnalyzerTests.cs | New test suite covering method/property + Task/ValueTask cases. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/snapshots/LookupReturnsNonNullableTypeAnalyzerTests.Method_NonNullableReturn_RaisesWarning.md | Snapshot baseline for non-nullable method return warning. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/snapshots/LookupReturnsNonNullableTypeAnalyzerTests.Method_NullableReturn_NoWarning.md | Snapshot baseline for nullable method return no-warning. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/snapshots/LookupReturnsNonNullableTypeAnalyzerTests.Method_TaskNonNullableReturn_RaisesWarning.md | Snapshot baseline for Task<T> non-nullable result warning. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/snapshots/LookupReturnsNonNullableTypeAnalyzerTests.Method_TaskNullableReturn_NoWarning.md | Snapshot baseline for Task<T?> no-warning. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/snapshots/LookupReturnsNonNullableTypeAnalyzerTests.Method_ValueTaskNonNullableReturn_RaisesWarning.md | Snapshot baseline for ValueTask<T> non-nullable result warning. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/snapshots/LookupReturnsNonNullableTypeAnalyzerTests.Method_NoLookupAttribute_NoWarning.md | Snapshot baseline ensuring no warning without [Lookup]. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/snapshots/LookupReturnsNonNullableTypeAnalyzerTests.Property_NonNullableReturn_RaisesWarning.md | Snapshot baseline for non-nullable property warning. |
| src/HotChocolate/Core/test/Types.Analyzers.Tests/snapshots/LookupReturnsNonNullableTypeAnalyzerTests.Property_NullableReturn_NoWarning.md | Snapshot baseline for nullable property no-warning. |
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This was referenced May 1, 2026
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Summary of the changes (Less than 80 chars)
#8072