fix(deconflict): rename CJS locals shadowing wrapped-ESM namespace objects by IWANABETHATGUY · Pull Request #9970 · rolldown/rolldown

IWANABETHATGUY · 2026-06-25T11:08:28Z

Standalone PR on main (the #9921 / #10006 stack it followed is now merged).

Extends the #9882 chunk-root shadowing fix to one more channel: a CJS closure local that shadows a wrapped-ESM namespace object read via require().

Problem

When a CJS-wrapped module require()s a wrapped-ESM module, the finalizer rewrites the require to (init_x(), __toCommonJS(xxx_exports)) — reading the importee's chunk-root namespace object. An author-local sharing that namespace object's final name shadows the read, producing a self-referential declaration:

var xxx_exports = (init_x(), __toCommonJS(xxx_exports)); // reads itself → undefined

→ TypeError: Cannot convert undefined or null to object at module-eval time.

Fix

Handle this in the precise rename_cjs_locals_shadowing_referenced_chunk_bindings post-pass — the same mechanism #9921 already uses for named-import and star-member shadowing. For each require() of a non-CommonJS importee (mirroring the finalizer's gate), rename a root-scope local that shares the importee namespace object's final name.

Why the post-pass rather than the chunk-root captured-name set: it runs after root-scope names are assigned, so it sees the namespace object's real (possibly renamed) name, and it only touches modules that actually reference the namespace — renaming the shadowing local, never the namespace.

Test

cjs_shadowing_require_namespace_object — throws __toCommonJS(undefined) without the fix, passes with it (the namespace keeps its bare name, the colliding local is suffixed). The shared sibling-suffix-skipping path of the renamer is already covered by cjs_shadowing_renamed_chunk_binding.

Full integration suite: 1778 passed, 0 failed.

codspeed-hq · 2026-06-25T11:16:15Z

Merging this PR will not alter performance

✅ 7 untouched benchmarks
⏩ 10 skipped benchmarks¹

_{Comparing fix/9882-wrapped-esm-namespace-object (22a0b55) with main (9570c95)²}

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. ↩
No successful run was found on refactor/9882-extract-captured-names (a5f5037) during the generation of this report, so main (9570c95) was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

IWANABETHATGUY · 2026-06-29T03:55:33Z

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IWANABETHATGUY · 2026-07-12T17:10:56Z

Merge activity

Jul 12, 5:10 PM UTC: The merge label 'graphite: merge-when-ready' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Jul 12, 5:13 PM UTC: IWANABETHATGUY added this pull request to the Graphite merge queue.
Jul 12, 5:18 PM UTC: Merged by the Graphite merge queue.

…jects (#9970) Standalone PR on `main` (the #9921 / #10006 stack it followed is now merged). Extends the #9882 chunk-root shadowing fix to one more channel: a CJS closure local that shadows a wrapped-ESM **namespace object** read via `require()`. ### Problem When a CJS-wrapped module `require()`s a wrapped-ESM module, the finalizer rewrites the require to `(init_x(), __toCommonJS(xxx_exports))` — reading the importee's chunk-root namespace object. An author-local sharing that namespace object's final name shadows the read, producing a self-referential declaration: ```js var xxx_exports = (init_x(), __toCommonJS(xxx_exports)); // reads itself → undefined ``` → `TypeError: Cannot convert undefined or null to object` at module-eval time. ### Fix Handle this in the **precise** `rename_cjs_locals_shadowing_referenced_chunk_bindings` post-pass — the same mechanism #9921 already uses for named-import and star-member shadowing. For each `require()` of a non-CommonJS importee (mirroring the finalizer's gate), rename a root-scope local that shares the importee namespace object's **final** name. Why the post-pass rather than the chunk-root captured-name set: it runs *after* root-scope names are assigned, so it sees the namespace object's real (possibly renamed) name, and it only touches modules that actually reference the namespace — renaming the shadowing **local**, never the namespace. ### Test `cjs_shadowing_require_namespace_object` — throws `__toCommonJS(undefined)` without the fix, passes with it (the namespace keeps its bare name, the colliding local is suffixed). The shared sibling-suffix-skipping path of the renamer is already covered by `cjs_shadowing_renamed_chunk_binding`. Full integration suite: 1778 passed, 0 failed.

@h-a-n-a

## [1.2.0] - 2026-07-15 ### 🚀 Features - dev: skip shipping factories for newly imported top-level modules (#10223) by @h-a-n-a - dev: per-client ship map for HMR patch sizing (#10208) by @h-a-n-a - dev: client-side HMR (#10164) by @h-a-n-a - dev: send a full-reload update to clients when a tsconfig changes (#10262) by @shulaoda - treat `import.meta['url']` and `import.meta['ROLLUP_FILE_URL_*']` as side-effect free (#10267) by @sapphi-red - rewrite `import.meta['url']` (#10251) by @sapphi-red - add `FILE_NOT_FOUND` error (#10220) by @sapphi-red - treat `import.meta.ROLLUP_FILE_URL_*` as side-effect free (#10217) by @sapphi-red ### 🐛 Bug Fixes - sourcemap: preserve unmapped boundaries during composition (#10254) by @hyfdev - `[format]` in `*FileNames` option for ESM format should be `es` instead of `esm` (#10214) by @sapphi-red - sourcemap: preserve coarse mappings during composition (#10249) by @hyfdev - rolldown_plugin_vite_import_glob: support tsconfig paths with `import.meta.glob` (#10167) by @sapphi-red - dev: clear tsconfig caches for bare full builds (#10276) by @shulaoda - dev: force a full rebuild when a tsconfig changes (#10261) by @shulaoda - treat rooted drive-less module ids as absolute in preserveModules naming (#10235) by @IWANABETHATGUY - watch: rebuild when tsconfig files change (#10258) by @shulaoda - watch: drop tsconfig-merged transform options on each rebuild (#10257) by @shulaoda - incorrect `EMPTY_IMPORT_META` warning for `import.meta.ROLLUP_FILE_URL_*` for CJS output (#10221) by @sapphi-red - deconflict: rename CJS locals shadowing wrapped-ESM namespace objects (#9970) by @IWANABETHATGUY - rolldown: drop the unused runtime module after entry-level external flattening (#10237) by @IWANABETHATGUY - rolldown: re-propagate has_dynamic_exports to transitive star importers (#10239) by @IWANABETHATGUY - tree-shaking: tree-shake destructured dynamic import namespace bindings (#10213) by @logaretm - s390x: use json-escape-simd 3.1.1 for big-endian JSON escaping fix (#10211) by @satyamg1620 ### 🚜 Refactor - dev: move full-reload to client side (#10207) by @h-a-n-a - readability follow-ups to the ReplaceWith migration (#10286) by @IWANABETHATGUY - replace take_in-then-write-back with ReplaceWith and by-value moves (#10285) by @Boshen - share the main resolver's cache with the transformer's tsconfig lookups (#10205) by @shulaoda - rolldown: extract the ns star-external __reExport emission rule into LinkingMetadata (#10238) by @IWANABETHATGUY - rolldown: unify link/generate diagnostics into a Diagnostics accumulator (#10234) by @IWANABETHATGUY - sourcemap_filenames: drop dead sourcemap-filename plumbing (#10189) by @IWANABETHATGUY - extract external import symbol merging into a method (#10224) by @IWANABETHATGUY - rolldown: skip CJS namespace merging under strict execution order (#10203) by @hyfdev - resolve the manual tsconfig per file instead of once at startup (#10200) by @shulaoda - rolldown: route interop ESM init emission through a shared init-target view (#10202) by @hyfdev - rolldown: collapse vestigial wrap-kind state and share chunk sort helper (#10201) by @hyfdev ### 📚 Documentation - show plugin kinds in JSDoc and each hook's description (#10218) by @sapphi-red - add an explanation about removing imports from external modules without any messages (#10215) by @sapphi-red ### ⚡ Performance - sourcemap: owned merge in SourceJoiner::join (4005->5 allocs/chunk) (#10250) by @Boshen - avoid redundant sourcemap string copies in collapse and minify paths (#10093) by @Boshen ### 🧪 Testing - code-splitting: establish strict-order review baselines (#10287) by @hyfdev - dev: add hot API test cases (#10181) by @h-a-n-a - code-splitting: normalize strict execution order variants (#10277) by @hyfdev - code-splitting: harden strict execution order coverage (#10252) by @hyfdev - code-splitting: add strict execution order regressions (#10253) by @hyfdev ### ⚙️ Miscellaneous Tasks - deps: update github actions (#10241) by @renovate[bot] - deps: update oxc to 0.140.0 (#10274) by @shulaoda - update Yunfei's GitHub username (#10275) by @hyfdev - deps: update napi (#10260) by @renovate[bot] - deps: update test262 submodule for tests (#10266) by @rolldown-guard[bot] - deps: update dependency vite-plus to v0.2.4 (#10256) by @renovate[bot] - deps: update napi (#10240) by @renovate[bot] - deps: update oxc resolver to v11.24.2 (#10245) by @renovate[bot] - deps: update rust crates (#10244) by @renovate[bot] - disable Renovate updates for idna_adapter (#10248) by @shulaoda - deps: update oxc resolver to v11.24.1 (#10232) by @renovate[bot] - deps: update rust crate oxc_sourcemap to v8.1.1 (#10233) by @renovate[bot] - deps: update dependency rolldown-plugin-dts to ^0.27.0 (#10206) by @renovate[bot] - deps: upgrade sugar_path to v3 (#10230) by @hyfdev - add `dist-*` to `.gitignore` in sourcemap-filenames/hash-final-content fixture (#10216) by @sapphi-red - deps: update dependency rust to v1.97.0 (#10209) by @renovate[bot] ### ❤️ New Contributors * @satyamg1620 made their first contribution in [#10211](#10211) Co-authored-by: shulaoda <[email protected]>

IWANABETHATGUY requested review from hyfdev and shulaoda as code owners June 25, 2026 11:08

IWANABETHATGUY assigned IWANABETHATGUY and unassigned IWANABETHATGUY Jun 25, 2026

IWANABETHATGUY marked this pull request as draft June 25, 2026 11:12

IWANABETHATGUY force-pushed the fix/9882-wrapped-esm-namespace-object branch from 0acfd6b to b07d5db Compare June 25, 2026 11:31

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IWANABETHATGUY force-pushed the fix/9882-wrapped-esm-namespace-object branch from b07d5db to 7da5f84 Compare June 29, 2026 03:55

IWANABETHATGUY mentioned this pull request Jun 29, 2026

fix(deconflict): rename CJS-wrapped locals that shadow chunk-root bindings #9921

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IWANABETHATGUY changed the base branch from fix/9882-cjs-wrapped-esm-shadowing to graphite-base/9970 June 29, 2026 04:09

IWANABETHATGUY force-pushed the fix/9882-wrapped-esm-namespace-object branch from 7da5f84 to 22a0b55 Compare June 29, 2026 04:09

IWANABETHATGUY changed the base branch from graphite-base/9970 to refactor/9882-extract-captured-names June 29, 2026 04:10

IWANABETHATGUY marked this pull request as ready for review June 29, 2026 04:10

IWANABETHATGUY mentioned this pull request Jun 29, 2026

refactor(deconflict): extract collect_chunk_scope_captured_names #10006

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shulaoda approved these changes Jun 29, 2026

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IWANABETHATGUY marked this pull request as draft June 29, 2026 04:11

IWANABETHATGUY force-pushed the refactor/9882-extract-captured-names branch from a5f5037 to cfad266 Compare June 29, 2026 05:24

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graphite-app Bot changed the base branch from refactor/9882-extract-captured-names to graphite-base/9970 June 29, 2026 06:08

graphite-app Bot closed this in 520d81e Jun 29, 2026

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IWANABETHATGUY changed the base branch from graphite-base/9970 to main June 29, 2026 06:36

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release: v1.2.0 #10292

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fix(deconflict): rename CJS locals shadowing wrapped-ESM namespace objects#9970

fix(deconflict): rename CJS locals shadowing wrapped-ESM namespace objects#9970
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