feat(tsconfig): walk transitive project-reference graph

[Boshen]

Stacked on #1162. Diff to review is the single commit on top.

Summary

Port typescript-go's initMapperWorker (internal/compiler/projectreferenceparser.go) so a parent tsconfig sees its references' references, not just direct ones. Closes the divergence called out in #1154's "Transitive references" caveat (and matched in typescript-go's getResolvedProjectReferenceToRedirect / isSourceOfProjectReferenceRedirect flow).

Changes

• references_resolved is populated recursively at load time. The references loop now calls load_tsconfig instead of cache.get_tsconfig directly, so each reference's own references are wired up.
• TsconfigResolveContext::loading_references breaks cycles in the reference graph (a → b → a) by skipping a tsconfig already mid-load. Mirrors typescript-go's seen set. Direct self-references (a → a) still surface as TsconfigSelfReference.
• resolve_tsconfig_solution and claims_ownership_of walk the graph breadth-first and pick the deepest project that owns the file — matching typescript-go's maps.Copy-into-deepest-wins behavior at line 99 of projectreferenceparser.go.
• Cache::resolve_tsconfig_path extracted from the existing dir/file/extensionless resolution so cycle keys are computed on the canonical tsconfig.json file path.

Test

project-references-transitive/: a 3-level chain (root → parent → child) where neither root nor parent owns the queried file but child does (via paths). Without transitive walking, resolve_tsconfig_solution would stop at parent and the @child/* alias wouldn't apply.

Known limits

Cyclic references (a → b → a) are broken, but the cached tsconfig that was mid-load when the cycle was detected has an incomplete references_resolved. Subsequent direct loads of that tsconfig return the cached (incomplete) version. Matches typescript-go's behavior where the cyclic edge is simply dropped via seen.AddIfAbsent.

[codecov]

Codecov Report

❌ Patch coverage is 93.97590% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.31%. Comparing base (5006e52) to head (a18b497).

Files with missing lines	Patch %	Lines
src/tsconfig.rs	89.47%	4 Missing ⚠️
src/tsconfig_resolver.rs	97.05%	1 Missing ⚠️

Additional details and impacted files

@@                                Coverage Diff                                 @@
##           05-27-refactor_tsconfig_precompute_owned_files    #1164      +/-   ##
==================================================================================
- Coverage                                           93.33%   93.31%   -0.03%     
==================================================================================
  Files                                                  22       22              
  Lines                                                4234     4265      +31     
==================================================================================
+ Hits                                                 3952     3980      +28     
- Misses                                                282      285       +3     

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Traverse transitive references during manual directory resolution

When a manual tsconfig is used with the directory-based resolve() API, this recursive load still leaves grandchildren nested under their parent, but resolve_references_then_self_paths only scans the root's direct references_resolved. In a graph like the new fixture (root -> parent -> child), resolver.resolve(child/src, "@child/foo") will never consult the child's paths and will fall back to the root config, even though resolve_file() passes because it selects the child solution first. The transitive graph needs to be traversed or flattened for this path-selection code as well.

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[codspeed]

Merging this PR will degrade performance by 4.09%

❌ 1 regressed benchmark
✅ 12 untouched benchmarks
⏩ 5 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	resolver_real[multi-thread]	387.9 µs	404.4 µs	-4.09%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing 05-27-feat_tsconfig_transitive_project_references (a18b497) with 05-27-refactor_tsconfig_precompute_owned_files (5006e52)}

Footnotes

1. 5 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩