fix(tsconfig): support transitive project references for paths resolution by stormslowly · Pull Request #213 · rstackjs/rspack-resolver

stormslowly · 2026-05-13T07:29:52Z

Summary

Make rspack-resolver's tsconfig project-reference handling match tsc's "nearest tsconfig wins" semantics and enhanced-resolve's recursive references: "auto" walk.

Three bugs are fixed:

Transitive references not walked. When the entry tsconfig declares references: [B] and B declares references: [C], a file inside C should resolve via C's own paths. Previously, only directly-listed references were loaded (one level deep) and TsConfig::resolve only iterated those, so requests from a transitively-referenced project's directory silently fell back to the entry tsconfig's paths.
extends not applied to referenced configs. A referenced project whose baseUrl/paths come from extends "../tsconfig.base.json" resolved as if it had no aliases. Pre-existing latent bug at depth 1 that the new transitive support makes easier to hit.
Cycles cause stack overflow. A pair of project references that point at each other (a → b → a) caused infinite recursion when references: "auto" recursively walked the graph.

Behavior comparison (file at `c/src/foo.ts`, chain `a → b → c`, entry `a/tsconfig.json`)

Resolver	Paths used
`tsc` (nearest tsconfig wins)	`c/tsconfig.json` ✅
`enhanced-resolve` `references: "auto"` (recursive)	`c/tsconfig.json` ✅
rspack-resolver before this PR	`a/tsconfig.json` ❌
rspack-resolver after this PR	`c/tsconfig.json` ✅

Changes

src/lib.rs
- Extract load_references from load_tsconfig. The helper recursively loads each reference's own references so transitive paths are honored.
- Extract merge_tsconfig_extends; call it on referenced tsconfigs (inside load_references) so a reference inherits its base config's baseUrl/paths before its own references are walked.
- Thread a visited: &mut FxHashSet<PathBuf> through load_references. Each tsconfig inserts its own path before walking its references; when a candidate reference is already in the chain, the cycle edge is cut (the reference is still attached so its paths are honored, but its nested references are not walked). Direct self-reference (A → A) detection via the existing equality check inside the cache callback is preserved.
src/tsconfig.rs: TsConfig::resolve recursively descends into nested references via a new find_reference_paths helper, returning the nearest reference whose base_path contains the requested path before falling back to the current tsconfig's own paths.
Fixtures:
- references-transitive/ — three-level chain app → project_b → project_c.
- references-extends/ — single-level reference whose paths come from extends "../tsconfig.base.json".
- references-cycle/ — a ↔ b pair.
Tests added in tsconfig_project_references:
- transitive_references — covers all three levels of the chain.
- references_with_extends — covers extends inheritance through a reference.
- cyclic_references — asserts resolution succeeds from both sides of an a ↔ b cycle without stack overflow.

Test plan

cargo test --all-features --lib -- --skip pnp — 125 passed (3 new tests + 122 existing, including auto, manual, disabled, self_reference, tsconfig_file_as_file_dependencies)
cargo clippy --all-features -- --deny warnings clean
cargo fmt --check clean
PnP tests fail both before and after this change (pre-existing fixture-install issue, unrelated)

When the entry tsconfig declares `references: [B]` and B declares `references: [C]`, a file inside C should resolve via C's own `paths`, matching `tsc`'s "nearest tsconfig wins" semantics and webpack's recursive `references: "auto"` walk. Previously, rspack-resolver loaded only the directly-listed references (one level deep) and `TsConfig::resolve` only iterated those direct references. As a result, requests from a transitively-referenced project's directory would silently fall back to the entry tsconfig's `paths` and resolve incorrectly. Changes: - `load_tsconfig` extracts `load_references` which recursively loads nested project references. Existing self-reference detection (A → A) is preserved; cycle detection across multiple levels is intentionally out of scope for this change. - `TsConfig::resolve` recursively descends into nested references via `find_reference_paths`, returning the nearest reference whose `base_path` contains the requested path before falling back to the current tsconfig.

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Pull request overview

This PR fixes TypeScript tsconfig project reference handling so paths resolution honors transitive references (A → B → C), matching TypeScript’s “nearest tsconfig wins” behavior and enhanced-resolve’s recursive reference walk.

Changes:

Recursively load referenced tsconfigs so nested reference configs (and their paths) are available during resolution.
Update TsConfig::resolve to recursively search nested references and use the nearest matching reference config for paths.
Add a new fixture and test covering a 3-level transitive reference chain.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/lib.rs	Extracts and adds recursive `load_references` to load nested project references.
src/tsconfig.rs	Adds recursive reference lookup (`find_reference_paths`) used by `TsConfig::resolve`.
src/tests/tsconfig_project_references.rs	Adds `transitive_references` test validating behavior across 3 reference levels.
fixtures/tsconfig/cases/references-transitive/app/tsconfig.json	Adds entry project tsconfig for transitive reference fixture.
fixtures/tsconfig/cases/references-transitive/app/aliased/index.ts	Adds aliased target file for `app` in fixture.
fixtures/tsconfig/cases/references-transitive/project_b/tsconfig.json	Adds middle project tsconfig referencing `project_c`.
fixtures/tsconfig/cases/references-transitive/project_b/src/aliased/index.ts	Adds aliased target file for `project_b` in fixture.
fixtures/tsconfig/cases/references-transitive/project_c/tsconfig.json	Adds leaf project tsconfig defining its own `paths`.
fixtures/tsconfig/cases/references-transitive/project_c/aliased/index.ts	Adds aliased target file for `project_c` in fixture.

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+  fn find_reference_paths(&self, path: &Path, specifier: &str) -> Option<Vec<PathBuf>> {
    for tsconfig in self
      .references
      .iter()
      .filter_map(|reference| reference.tsconfig.as_ref())
    {
+      if let Some(nested) = tsconfig.find_reference_paths(path, specifier) {
+        return Some(nested);
+      }
      if path.starts_with(tsconfig.base_path()) {
-        return tsconfig.resolve_path_alias(specifier);
+        return Some(tsconfig.resolve_path_alias(specifier));
      }


codspeed-hq · 2026-05-13T07:35:43Z

Merging this PR will not alter performance

✅ 12 untouched benchmarks

_{Comparing feat/tsconfig-transitive-references (23b8954) with main (8975e38)}

When a project reference uses `extends` to inherit its `baseUrl`/`paths` from a shared base config, those fields must be merged before the reference is consulted for resolution. The previous flow loaded each reference through `cache.tsconfig` and only ran the extends-merging logic on the entry tsconfig, so a transitively-referenced project whose aliases live in an extended base file would resolve as if it had no aliases at all. This was a pre-existing latent bug at depth 1 — direct references with `extends` did not inherit their aliases either — that the new transitive-references support made easier to hit. Changes: - Extract `merge_tsconfig_extends` from `load_tsconfig` and call it from `load_references`' inner callback after the self-reference check, before recursing into nested references. - Update the `references-transitive` fixture: `project_c` now reads its `paths` from a sibling `tsconfig.base.json` via `extends`. The existing `transitive_references` test fails before this fix (NotFound) and passes after. Detected via Codex review of #213.

Add a dedicated test (`references_with_extends`) and fixture (`references-extends/`) that exercises the fix from the previous commit in isolation: a single-level reference whose `baseUrl`/`paths` are inherited via `extends "../tsconfig.base.json"`. Without `merge_tsconfig_extends` being applied to the reference, the test fails with `NotFound` — confirming the test would have caught the latent extends-on-reference bug. Also revert the `references-transitive` fixture so it focuses purely on multi-level walking; the extends-merging behavior is now covered by the new fixture and test.

A pair of project references that point at each other (a → b → a) previously caused infinite recursion when `references: "auto"` recursively loaded the graph, blowing the test thread's stack. Add a `visited` set threaded through `load_references`. Each tsconfig inserts its own path before walking its references. When a candidate reference's loaded path is already in the chain, the cycle edge is cut: the reference is still attached so its own `paths` are honored, but its nested references are not walked. Includes a `references-cycle` fixture (a ↔ b) and a `cyclic_references` test that asserts resolution succeeds from both sides without stack overflow. Direct self-reference (A → A) detection via the existing equality check inside the cache callback is preserved.

Copilot AI review requested due to automatic review settings May 13, 2026 07:29

Copilot started reviewing on behalf of stormslowly May 13, 2026 07:30 View session

chatgpt-codex-connector Bot reviewed May 13, 2026

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Comment thread src/lib.rs Outdated

style: format fixture tsconfig.json with prettier

415504a

Copilot AI reviewed May 13, 2026

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stormslowly added 3 commits May 13, 2026 16:04

stormslowly changed the title ~~fix(tsconfig): honor transitive project references for paths resolution~~ fix(tsconfig): support transitive project references for paths resolution May 13, 2026

stormslowly requested a review from hardfist May 13, 2026 09:40

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fix(tsconfig): support transitive project references for paths resolution#213

fix(tsconfig): support transitive project references for paths resolution#213
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stormslowly commented May 13, 2026 •

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codspeed-hq Bot commented May 13, 2026 •

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stormslowly commented May 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Behavior comparison (file at c/src/foo.ts, chain a → b → c, entry a/tsconfig.json)

Changes

Test plan

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codspeed-hq Bot commented May 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Merging this PR will not alter performance

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stormslowly commented May 13, 2026 •

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Behavior comparison (file at `c/src/foo.ts`, chain `a → b → c`, entry `a/tsconfig.json`)

codspeed-hq Bot commented May 13, 2026 •

edited

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