refactor(analyzers): address review feedback from #6917

[thomhurst]

Follow-up to #6917, which merged before these review-feedback fixes were pushed.

Changes

• MigrationNamespaceHelper: split the dotted namespace path once per compilation instead of once per referenced assembly, and document why the probe walks every namespace (including extern-aliased references).
• BaseMigrationAnalyzer / XUnitMigrationAnalyzer: use StringComparison.Ordinal for namespace-prefix checks in both the cheap gate and the semantic checks, so the two can never disagree under a non-invariant culture.
• CombinedDataSourceAnalyzer: document why the early return is safe (every class-level rule reads class attributes or constructor parameters).
• DisposableFieldPropertyAnalyzer: note on SemanticModelCache scope and thread safety.
• Tests: property getters/setters are not treated as constructors, SetupAsync or test methods now that the analyzers resolve via ContainingSymbol (InstanceValuesInTestClassAnalyzerTests, WebApplicationFactoryAccessAnalyzerTests).

Declined from #6917 review

• Sharing one namespace walk across the three migration analyzers: each looks for a different name and short-circuits on first match; a shared per-compilation cache would cost more than it saves.
• Extern-alias-only test: the analyzer-test helpers can't configure aliased references; behaviour is documented in the new comment.

Testing

• TUnit.Analyzers.Tests (net10.0): 829 passed, 1 skipped, 0 failed
• TUnit.AspNetCore.Analyzers.Tests (net10.0): 29/29 passed

Summary by CodeRabbit

• Bug Fixes
  • NUnit and xUnit migration checks now match namespace names consistently and case-sensitively, avoiding incorrect results for names with Unicode characters that may otherwise compare similarly.
  • Analyzer checks no longer report diagnostics for the tested assignments to instance fields from property accessors or for accessing factory and service properties within property getters.

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-28T20:57:16.224403Z	acfbecc	PR opened

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Configuration used: Organization UI

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📥 Commits

Reviewing files that changed from the base of the PR and between acfbecc and 12bcd21.

📒 Files selected for processing (4)

• src/TUnit.Analyzers/CombinedDataSourceAnalyzer.cs
• src/TUnit.Analyzers/Migrators/XUnitMigrationAnalyzer.cs
• tests/TUnit.Analyzers.Tests/NUnitMigrationAnalyzerTests.cs
• tests/TUnit.Analyzers.Tests/XUnitMigrationAnalyzerTests.cs

🚧 Files skipped from review as they are similar to previous changes (1)

• src/TUnit.Analyzers/CombinedDataSourceAnalyzer.cs

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📝 Walkthrough

Walkthrough

The changes clarify analyzer assumptions, use ordinal namespace-prefix comparisons in migration analyzers, reuse split namespace segments, and add tests for property-accessor cases that should not produce diagnostics.

Changes

Migration namespace matching

Layer / File(s)	Summary
Namespace matching and traversal src/TUnit.Analyzers/Migrators/Base/BaseMigrationAnalyzer.cs, src/TUnit.Analyzers/Migrators/Base/MigrationNamespaceHelper.cs, src/TUnit.Analyzers/Migrators/XUnitMigrationAnalyzer.cs, tests/TUnit.Analyzers.Tests/NUnitMigrationAnalyzerTests.cs, tests/TUnit.Analyzers.Tests/XUnitMigrationAnalyzerTests.cs	Migration analyzers use ordinal, case-sensitive namespace-prefix checks. Namespace traversal splits the dotted path once and passes the segments through source and referenced-assembly checks. NUnit and xUnit tests cover Unicode namespace matching.

Property-accessor analyzer tests

Layer / File(s)	Summary
Property-accessor diagnostic coverage tests/TUnit.Analyzers.Tests/InstanceValuesInTestClassAnalyzerTests.cs, tests/TUnit.AspNetCore.Analyzers.Tests/WebApplicationFactoryAccessAnalyzerTests.cs	Added tests asserting no analyzer diagnostic for instance-field assignments in property accessors and for Factory or Services accesses in property getters.

Analyzer assumptions and cache lifetime

Layer / File(s)	Summary
Rule inputs and cache constraints src/TUnit.Analyzers/CombinedDataSourceAnalyzer.cs, src/TUnit.Analyzers/DisposableFieldPropertyAnalyzer.cs	Comments document the early-return inputs used by class-level rules and state that SemanticModelCache is not thread-safe, retains semantic models, and must not be stored or shared across analysis callbacks.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Refactor

Merge Risk: ⚪ Minimal · up to 12bcd

No merge-blocking issue is established for the namespace-matching changes or analyzer tests; the PR is mergeable after normal checks.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 16.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 25 functions across 9 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately identifies this pull request as a refactor that addresses review feedback from #6917. It is broad and does not name the namespace-matching and analyzer-test changes, but it remain…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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_{A rabbit checks each namespace name,
Ordinal rules keep matches plain.
Split paths pass along their parts,
Getter tests check analyzer starts.
Cache notes stay beside the code,
Then off the rabbit hops down the road.}

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[github-actions]

Review

I read the diff and found no blocking issues. I didn't build the PR or run its tests. The tests ran only in the PR author's description (829 passed in TUnit.Analyzers.Tests, 29/29 in TUnit.AspNetCore.Analyzers.Tests).

• MigrationNamespaceHelper: The dotted path is now split once per compilation instead of once per referenced assembly, which removes repeated allocations from a startup path. The new remarks explain why the namespace walk is exhaustive.
• StringComparison.Ordinal: It is now used in both the cheap gate and the semantic checks, so the two can't disagree under a non-invariant culture. The change is consistent across BaseMigrationAnalyzer and XUnitMigrationAnalyzer.
• Comments: The notes on the early return in CombinedDataSourceAnalyzer and on SemanticModelCache are accurate and useful.
• Tests: The new cases cover property accessors not being treated as constructors, SetupAsync or test methods. That matches the ContainingSymbol resolution change from perf(analyzers): cut binding and symbol lookups in analyzer hot paths (TUnit.Analyzers -89% on TestProject) #6917.

Optional suggestion: the StartsWith("Xunit", StringComparison.Ordinal) call is repeated about six times in XUnitMigrationAnalyzer. A small IsXunitNamespace(INamespaceSymbol?) helper would keep the gate and the checks in sync by construction. It isn't required for this PR.

Approving in spirit.

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Actionable comments posted: 1

---

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Inline comments:
Review comments at @src/TUnit.Analyzers/CombinedDataSourceAnalyzer.cs:
- Line 39: Update the rule-placement guidance in CombinedDataSourceAnalyzer to
say that class-level rules requiring neither input must run before the early
return, so they are not skipped when both inputs are empty.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: 720a26dd-299c-4b10-9c7f-aea381c98361

📥 Commits

Reviewing files that changed from the base of the PR and between 6071342 and acfbecc.

📒 Files selected for processing (7)

• src/TUnit.Analyzers/CombinedDataSourceAnalyzer.cs
• src/TUnit.Analyzers/DisposableFieldPropertyAnalyzer.cs
• src/TUnit.Analyzers/Migrators/Base/BaseMigrationAnalyzer.cs
• src/TUnit.Analyzers/Migrators/Base/MigrationNamespaceHelper.cs
• src/TUnit.Analyzers/Migrators/XUnitMigrationAnalyzer.cs
• tests/TUnit.Analyzers.Tests/InstanceValuesInTestClassAnalyzerTests.cs
• tests/TUnit.AspNetCore.Analyzers.Tests/WebApplicationFactoryAccessAnalyzerTests.cs

Included review availability: This review used your included allowance. Your plan provides up to 8 included reviews per hour; 5 remain after this review.

[greptile-apps]

Confidence Score: 5/5

[Medium risk] Refactors code analyzers and adds test coverage.

The PR appears safe to merge; no outstanding blocking issue was identified.

Summary

The PR makes migration namespace checks ordinal, reuses a split namespace path, documents analyzer assumptions, and adds regression tests for namespace comparisons and property accessors.

_{Reviews (2) · Last reviewed commit: "refactor(analyzers): share xUnit namespa..."}

[thomhurst]

Took the suggestion to add a helper in 12bcd21. XUnitMigrationAnalyzer now has one IsXunitNamespace(INamespaceSymbol?) method, and both the compilation-start gate and every semantic check call it, so the two can't drift apart.

[github-actions]

Review

Small, well-scoped follow-up to #6917. I read the diff and did not run the tests.

• Ordinal comparisons: XUnitMigrationAnalyzer now uses a single IsXunitNamespace helper for both the compilation-start gate and the semantic checks, so the two can't drift apart. BaseMigrationAnalyzer gets StringComparison.Ordinal in the same places.
• Culture-sensitive tests: the combining-mark (U+0301) and ignorable-character (U+034F) namespaces are a good way to check that ordinal and culture-sensitive comparisons disagree. Unicode escapes are processed inside identifiers even in raw string literals, so the tests do exercise what they claim to.
• MigrationNamespaceHelper: hoisting Split('.') out of the per-assembly loop is a straightforward win. The remarks explain why the walk covers every namespace, and I agree with declining a shared cross-analyzer cache.
• New accessor tests: these cover property getters and setters, which the analyzers now resolve through ContainingSymbol.
• Comments: the CombinedDataSourceAnalyzer and SemanticModelCache comments are accurate.

Nit, not blocking: NUnitMigrationAnalyzerTests and XUnitMigrationAnalyzerTests aren't laid out the same way. The Xunit test wraps the whole source in a diagnostic span, while the NUnit one spans only the class. Both should be fine as long as each matches where its analyzer reports.

LGTM.