[vitest-plugin] Fix resolve.preserveSymlinks with isolated node_modules by gpanders · Pull Request #16609 · cloudflare/workers-sdk

gpanders · 2026-10-30T20:53:39Z

With resolve.preserveSymlinks: true in a pnpm project, tests fail to start with No such module ".../node_modules/vitest/dist/chai". The plugin sends every dependency through Vite, including Vitest itself. With preserveSymlinks, Vite loads each package from its symlink in node_modules. pnpm puts a package's own dependencies only next to the package's real location, so Vite can't find them from the symlink.

With preserveSymlinks enabled:

Files under node_modules resolve to their real path, if the real path is also under node_modules. Packages linked from outside node_modules (npm link, file:) keep their symlinked path, so they still find peer dependencies in the project.
This applies to both import and require().
fs.realpathSync from node:fs finds real paths. Bazel's rules_js patches this function to keep paths inside the sandbox, and it keeps mapped drive letters on Windows.

Projects without preserveSymlinks behave as before. The plugin's resolveId hook now runs before the hooks of other plugins, but it returns the same results.

Related: CC-9111

Tests
- Tests included/updated
- Automated tests not possible - manual testing has been completed as follows:
- Additional testing not necessary because:
Public documentation
- Cloudflare docs PR(s):
- Documentation not necessary because: bug fix

changeset-bot · 2026-10-30T20:53:45Z

🦋 Changeset detected

Latest commit: efadc13

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@cloudflare/vitest-plugin	Patch

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workers-devprod · 2026-10-30T20:54:09Z

Codeowners approval required for this PR:

@cloudflare/wrangler

Show detailed file reviewers

.changeset/vitest-plugin-preserve-symlinks.md: [@cloudflare/wrangler]
packages/vitest-plugin/src/pool/helpers.ts: [@cloudflare/wrangler]
packages/vitest-plugin/src/pool/module-fallback.ts: [@cloudflare/wrangler]
packages/vitest-plugin/src/pool/plugin.ts: [@cloudflare/wrangler]
packages/vitest-plugin/test/module-fallback.test.ts: [@cloudflare/wrangler]
packages/vitest-plugin/test/preserve-symlinks.test.ts: [@cloudflare/wrangler]

ask-bonk · 2026-10-30T20:55:20Z

I'm Bonk, and I've done a quick review of your PR.

Adds pnpm-safe symlink canonicalization for Vitest module resolution.

P1: Posted 1 actionable inline suggestion.

github run

clanky-the-clanker

Superseded by the review of efadc13d.

This review, of 2743bc8a

✅ Approved — No issues found. The real-path mapping only runs when resolve.preserveSymlinks is on, maps each id once for both import and require(), and is covered by tests.

_{The decision is advisory: this review is a comment and never approves, blocks or requests changes on the pull request.}

✅ All checks passed

🚀 Release: ✅ LGTM

The changeset is present and appropriate for a bug fix. Risk: low.

🔒 Security: ✅ LGTM

The change only maps module ids that Vite has already resolved to their real paths under node_modules. It adds no new input, endpoint or secret.

📖 AGENTS.md: ✅ LGTM

No issues found.

📋 Code Quality: ✅ LGTM

The real-path mapping is applied exactly once per resolution: by the pre-order resolveId hook for import, and by the module fallback service for require(). Virtual, relative and cloudflare:test ids are unaffected, query suffixes are kept, and the test mocks were updated for the new config field.

⚡ Performance: ✅ LGTM

The cost is one synchronous realpathSync per resolved id under node_modules, and only when preserveSymlinks is enabled.

📝 Documentation: ✅ LGTM

No issues found.

_{Reviewed commit: 2743bc8a}

pkg-pr-new · 2026-10-30T20:57:34Z

@cloudflare/autoconfig

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@cloudflare/build-output-utils

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@cloudflare/codemods

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@cloudflare/config

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@cloudflare/containers-shared

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create-cloudflare

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@cloudflare/deploy-helpers

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@cloudflare/kv-asset-handler

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miniflare

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@cloudflare/pages-functions

npm i https://pkg.pr.new/@cloudflare/pages-functions@16609

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@16609

@cloudflare/runtime-types

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@cloudflare/unenv-preset

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@cloudflare/vite-plugin

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@cloudflare/vitest-plugin

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@cloudflare/workers-auth

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@cloudflare/workers-editor-shared

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@cloudflare/workers-utils

npm i https://pkg.pr.new/@cloudflare/workers-utils@16609

wrangler

npm i https://pkg.pr.new/wrangler@16609

commit: efadc13

With `resolve.preserveSymlinks: true` in a pnpm project, tests fail to start with `No such module ".../node_modules/vitest/dist/chai"`. The plugin sends every dependency through Vite, including Vitest itself. With `preserveSymlinks`, Vite loads each package from its symlink in `node_modules`. pnpm puts a package's own dependencies only next to the package's real location, so Vite can't find them from the symlink. With `preserveSymlinks` enabled: - Files under `node_modules` resolve to their real path, if the real path is also under `node_modules`. Packages linked from outside `node_modules` (`npm link`, `file:`) keep their symlinked path, so they still find peer dependencies in the project. - This applies to both `import` and `require()`. - `fs.realpathSync` from `node:fs` finds real paths. Bazel's rules_js patches this function to keep paths inside the sandbox, and it keeps mapped drive letters on Windows. Projects without `preserveSymlinks` behave as before. The plugin's `resolveId` hook now runs before the hooks of other plugins, but it returns the same results. Related: CC-9111

clanky-the-clanker

✅ Approved — No issues found. The real-path mapping runs only when resolve.preserveSymlinks is enabled, it keeps query and hash suffixes, and tests cover it.

_{The decision is advisory: this review is a comment and never approves, blocks or requests changes on the pull request.}

✅ All checks passed

🚀 Release: ✅ LGTM

The pull request includes a changeset, which fits a bug fix. Risk: low.

🔒 Security: ✅ LGTM

The change only rewrites module ids that Vite has already resolved. It keeps the rewritten path only when that path is still under node_modules, and it adds no new input, endpoint or secret.

📖 AGENTS.md: ✅ LGTM

No issues found.

📋 Code Quality: ✅ LGTM

Each resolution is mapped to its real path exactly once: by the pre-order resolveId hook for import, and by the module fallback service for require(). realPackagePath keeps ?query and #hash suffixes and, like Vite, first tries a # as part of the file name. It falls back to the original id when the real path leaves node_modules.

⚡ Performance: ✅ LGTM

The new cost is one synchronous realpathSync per resolved id under node_modules, and only when preserveSymlinks is enabled. Vite caches the extra this.resolve call that uses skipSelf.

📝 Documentation: ✅ LGTM

No issues found.

_{Reviewed commit: efadc13d}

gpanders requested a review from workers-devprod as a code owner October 30, 2026 20:53

workers-devprod added this to workers-sdk Oct 30, 2026

github-project-automation Bot moved this to Untriaged in workers-sdk Oct 30, 2026

workers-devprod requested review from a team and petebacondarwin and removed request for a team October 30, 2026 20:54

ask-bonk Bot reviewed Oct 30, 2026

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gpanders force-pushed the ganders/CC-9111 branch from 2743bc8 to efadc13 Compare October 30, 2026 21:21

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[vitest-plugin] Fix resolve.preserveSymlinks with isolated node_modules - #16609

[vitest-plugin] Fix resolve.preserveSymlinks with isolated node_modules#16609
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🚀 Release: ✅ LGTM

🔒 Security: ✅ LGTM

📖 AGENTS.md: ✅ LGTM

📋 Code Quality: ✅ LGTM

⚡ Performance: ✅ LGTM

📝 Documentation: ✅ LGTM

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🚀 Release: ✅ LGTM

🔒 Security: ✅ LGTM

📖 AGENTS.md: ✅ LGTM

📋 Code Quality: ✅ LGTM

⚡ Performance: ✅ LGTM

📝 Documentation: ✅ LGTM

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