fix: emit separate __toESM bindings for mixed ESM/CJS external imports by IWANABETHATGUY · Pull Request #8987 · rolldown/rolldown

IWANABETHATGUY · 2026-04-01T16:53:52Z

Summary

When a CJS/IIFE/UMD chunk has both ESM and non-ESM importers of the same external module, emits two __toESM bindings — one with node-mode (__toESM(x, 1)) for ESM importers and one without for non-ESM importers
Previously, all importers shared a single binding, which broke interop when the external has __esModule: true
Also fixes IIFE/UMD format which never passed the node-mode flag at all

Fixes #8842

Test plan

Added 8842 test (single-mode: ESM importer of external in CJS output)
Added 8842_mixed_chunk test (mixed-mode: both .mjs and .js importers of same external)
All 1665 integration tests pass

IWANABETHATGUY · 2026-04-01T16:54:06Z

fix: emit separate __toESM bindings for mixed ESM/CJS external imports #8987 👈 (View in Graphite)
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socket-security · 2026-04-06T03:48:14Z

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	oxc-walker@0.5.2
	oxfmt@0.43.0
	oxc-transform@0.123.0

View full report

codspeed-hq · 2026-04-06T03:54:24Z

Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 10 skipped benchmarks¹

_{Comparing 04-01-fix_8843 (e6fd33f) with main (a48ca34)}

10 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. ↩

@sapphi-red

## [1.0.0-rc.14] - 2026-04-08 ### 🚀 Features - rust: add `disable_panic_hook` feature to disable the panic hook (#9023) by @sapphi-red - support inlineConst for CJS exports accessed through module.exports (#8976) by @h-a-n-a ### 🐛 Bug Fixes - rolldown_plugin_vite_import_glob: normalize resolved alias path to prevent double slashes (#9032) by @shulaoda - rolldown_plugin_vite_import_glob: follow symlinks in file scanning (#9000) by @Copilot - wrap CJS entry modules for IIFE/UMD when using exports/module (#8999) by @IWANABETHATGUY - emit separate __toESM bindings for mixed ESM/CJS external imports (#8987) by @IWANABETHATGUY - tree-shake dead dynamic imports to side-effect-free CJS modules (#8529) by @sapphi-red - skip inlining stale CJS export constants on module.exports reassignment (#8990) by @IWANABETHATGUY ### 🚜 Refactor - generator: migrate ecma formatting from npx oxfmt to vp fmt (#9022) by @shulaoda - generator: replace npx oxfmt with vp fmt for ecma formatting (#9021) by @shulaoda ### 📚 Documentation - contrib-guide: mention that running tests on older Node.js version will have different stat results (#8996) by @claude ### ⚙️ Miscellaneous Tasks - deps: update npm packages (#9002) by @renovate[bot] - deps: update dependency @napi-rs/cli to v3.6.1 (#9034) by @renovate[bot] - deps: upgrade oxc to 0.124.0 (#9018) by @shulaoda - deps: update test262 submodule for tests (#9010) by @sapphi-red - deps: update dependency oxfmt to ^0.44.0 (#9012) by @renovate[bot] - deps: update dependency vite to v8.0.5 [security] (#9009) by @renovate[bot] - deps: update dependency vite-plus to v0.1.16 (#9008) by @renovate[bot] - deps: update rust crates (#9003) by @renovate[bot] - deps: update github-actions (#9004) by @renovate[bot] - deps: update dependency lodash-es to v4.18.1 [security] (#8992) by @renovate[bot] - deps: update crate-ci/typos action to v1.45.0 (#8988) by @renovate[bot] - upgrade oxc npm packages to 0.123.0 (#8985) by @shulaoda ### ◀️ Revert - "chore(deps): update dependency oxfmt to ^0.44.0 (#9012)" (#9019) by @shulaoda Co-authored-by: shulaoda <165626830+shulaoda@users.noreply.github.com>

github-actions Bot assigned IWANABETHATGUY Apr 1, 2026

IWANABETHATGUY changed the title ~~fix: 8843~~ fix: emit separate __toESM bindings for mixed ESM/CJS external imports Apr 1, 2026

IWANABETHATGUY force-pushed the 04-01-fix_8843 branch 2 times, most recently from 4abf0b6 to 5b95891 Compare April 2, 2026 02:23

fix: 8843

e6fd33f

IWANABETHATGUY force-pushed the 04-01-fix_8843 branch from 5b95891 to e6fd33f Compare April 6, 2026 03:47

IWANABETHATGUY requested review from hyf0 and shulaoda April 6, 2026 03:48

IWANABETHATGUY marked this pull request as ready for review April 6, 2026 03:48

IWANABETHATGUY requested a review from h-a-n-a April 6, 2026 03:48

h-a-n-a approved these changes Apr 6, 2026

View reviewed changes

IWANABETHATGUY merged commit 1a12fe7 into main Apr 6, 2026
32 checks passed

IWANABETHATGUY deleted the 04-01-fix_8843 branch April 6, 2026 04:02

This was referenced Apr 8, 2026

release: v1.0.0-rc.14 #9029

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release: v1.0.0-rc.14 #9035

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fix: emit separate __toESM bindings for mixed ESM/CJS external imports#8987

fix: emit separate __toESM bindings for mixed ESM/CJS external imports#8987
IWANABETHATGUY merged 1 commit intomainfrom
04-01-fix_8843

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IWANABETHATGUY commented Apr 1, 2026

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Merging this PR will not alter performance

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IWANABETHATGUY commented Apr 1, 2026 •

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