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fix(loader): preserve resolved format for extensionless entrypoints - #300
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pabloerhard wants to merge 5 commits into
Open
pabloerhard wants to merge 5 commits into
pabloerhard wants to merge 5 commits into
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Keep the CommonJS fallback only when the upstream resolver supplies no format. This prevents extensionless ESM CLI launchers, such as TypeScript 7's tsc, from being loaded as CommonJS and triggering ERR_REQUIRE_CYCLE_MODULE. Add regression coverage for extensionless ESM and CommonJS entrypoints with asynchronous and synchronous loader hooks.
Native extensionless ESM support starts in Node 18.19 and 20.10. Keep that case on supported runtimes and exercise upstream-resolved ESM formats on older runtimes instead. Compose the asynchronous test loader directly to also cover Node 18.5, which predates loader chaining. Retain CommonJS entrypoint coverage across all supported runtimes.
Test the latest TypeScript in its own dependency tree so compiler-API consumers can use supported peer versions. Separate Remix's TypeScript 5 peer from the TypeScript 6 peer shared by SvelteKit and typescript-estree. Retain all 250 baseline and instrumented export comparisons. Replace generated manifests on reruns and fail immediately if installation fails, rather than testing an incomplete dependency tree.
Install every dependency group in sibling directories so no tree resolves packages from another one's node_modules, and define the groups in a single table. Pin the shared TypeScript peer to ~6.0.0 because typescript-estree rejects 6.1, and drop stale lockfiles before reinstalling.
pabloerhard
marked this pull request as ready for review
October 5, 2026 17:32
rochdev
approved these changes
Oct 7, 2026
BridgeAR
reviewed
Oct 15, 2026
Return only the URL and format for extensionless entrypoints, matching the original result shape. The other resolve fields are not needed once the upstream format is preserved.
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Problem
When IITM resolves an extensionless entrypoint, such as a CLI file in
bin/, it always reports the format ascommonjs.Node 18.19+ and 20.10+ can now resolve extensionless entrypoints as ESM, but IITM still overrides that result. TypeScript 7's
bin/tscis in a"type": "module"package. With IITM active, Node loads it as CommonJS and fails withERR_REQUIRE_CYCLE_MODULE.Fix
Use
commonjsonly when the resolver before IITM didn't return a format:Resolves: DataDog/dd-trace-js#10533