refactor(rolldown): skip CJS namespace merging under strict execution order#10203
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Pull request overview
Disables the “safely merge CJS namespace” size optimization when output.strictExecutionOrder is enabled, ensuring CommonJS require() evaluation stays anchored to each importer’s original call site to preserve observable execution order in strict mode.
Changes:
- Early-return from
determine_safely_merge_cjs_nsunder strict execution order, preventing cross-importer namespace merging. - Update the existing strict-only
react-likesnapshot to reflect the non-merged CJS namespace behavior. - Add a new strict fixture (
cjs_ns_merge_skipped) that demonstrates the non-strict merged output vs strict non-merged output in one snapshot.
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Show a summary per file
| File | Description |
|---|---|
| crates/rolldown/src/stages/link_stage/determine_module_exports_kind.rs | Skips building safely_merge_cjs_ns_map under strict execution order to prevent require() relocation. |
| crates/rolldown/tests/rolldown/function/experimental/strict_execution_order/react-like/artifacts.snap | Updates strict snapshot to show the split require/__toESM behavior. |
| crates/rolldown/tests/rolldown/function/experimental/strict_execution_order/cjs_ns_merge_skipped/_config.json | Adds a variant to snapshot both default and strict outputs for the new fixture. |
| crates/rolldown/tests/rolldown/function/experimental/strict_execution_order/cjs_ns_merge_skipped/main.js | New test entry that imports the same CJS module as another ESM module. |
| crates/rolldown/tests/rolldown/function/experimental/strict_execution_order/cjs_ns_merge_skipped/lib.js | New test module that also imports the same CJS module, enabling the merge-vs-skip contrast. |
| crates/rolldown/tests/rolldown/function/experimental/strict_execution_order/cjs_ns_merge_skipped/cjs.cjs | New CJS module with an observable side effect (console.log) to validate evaluation ordering. |
| crates/rolldown/tests/rolldown/function/experimental/strict_execution_order/cjs_ns_merge_skipped/artifacts.snap | New snapshot demonstrating merged namespace in default mode and per-importer namespaces in strict mode. |
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… order (#10203) **What this does (and doesn't).** Under `output.strictExecutionOrder`, skip the "safely merge CJS namespace" optimization: `determine_safely_merge_cjs_ns` now early-returns when strict execution order is enabled. This is the one piece of strict-gated link-stage groundwork that stands on its own. It does NOT change flag-off behavior, and it deliberately excludes the feature's other strict bookkeeping (`star_export_record_by_name`, `execution_dependencies`, star-reexport path recording) because none of it has a reader in this PR — that lands with the analysis that consumes it. **Why.** The optimization lets several ESM importers of the same CommonJS module share one namespace binding, which relocates the surviving `require()` to whichever importer statement stays included. That reordering can move a CommonJS module's evaluation past statements that should run after it — an execution-order break that no amount of wrapping can repair. Under strict execution order, correctness must win over the small byte saving, so we keep each importer's own call site (the CJS wrapper memoizes, so the module still evaluates exactly once). The added `cjs_ns_merge_skipped` fixture shows the contrast directly: the default variant shares one `import_cjs`, while the strict variant gives `lib.js` and `main.js` their own bindings materialized at their own use sites. **Validation.** `cargo test -p rolldown --test integration`: passing (same 5 pre-existing environment-only failures as the rest of the stack). `cargo clippy -p rolldown --all-targets -- -D warnings` is clean and `cargo fmt --all` produces no diff. Flag-off output is byte-identical — no non-strict snapshot changed. Exactly one existing strict-only snapshot changed, `react-like`: the shared `import_commonjs = __toESM(require_commonjs())` is now split so `lib.js` does a bare `require_commonjs()` and `main.js` materializes the namespace at its own use site. That is the intended strict-only correctness improvement. **Stack.** Top of a three-layer stack slicing the `output.strictExecutionOrder` work; builds on (1) wrap-kind / chunk-graph cleanup and (2) the interop init-target view. The strict analysis and code generation that consume the deferred bookkeeping come in later layers.
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… order (#10203) **What this does (and doesn't).** Under `output.strictExecutionOrder`, skip the "safely merge CJS namespace" optimization: `determine_safely_merge_cjs_ns` now early-returns when strict execution order is enabled. This is the one piece of strict-gated link-stage groundwork that stands on its own. It does NOT change flag-off behavior, and it deliberately excludes the feature's other strict bookkeeping (`star_export_record_by_name`, `execution_dependencies`, star-reexport path recording) because none of it has a reader in this PR — that lands with the analysis that consumes it. **Why.** The optimization lets several ESM importers of the same CommonJS module share one namespace binding, which relocates the surviving `require()` to whichever importer statement stays included. That reordering can move a CommonJS module's evaluation past statements that should run after it — an execution-order break that no amount of wrapping can repair. Under strict execution order, correctness must win over the small byte saving, so we keep each importer's own call site (the CJS wrapper memoizes, so the module still evaluates exactly once). The added `cjs_ns_merge_skipped` fixture shows the contrast directly: the default variant shares one `import_cjs`, while the strict variant gives `lib.js` and `main.js` their own bindings materialized at their own use sites. **Validation.** `cargo test -p rolldown --test integration`: passing (same 5 pre-existing environment-only failures as the rest of the stack). `cargo clippy -p rolldown --all-targets -- -D warnings` is clean and `cargo fmt --all` produces no diff. Flag-off output is byte-identical — no non-strict snapshot changed. Exactly one existing strict-only snapshot changed, `react-like`: the shared `import_commonjs = __toESM(require_commonjs())` is now split so `lib.js` does a bare `require_commonjs()` and `main.js` materializes the namespace at its own use site. That is the intended strict-only correctness improvement. **Stack.** Top of a three-layer stack slicing the `output.strictExecutionOrder` work; builds on (1) wrap-kind / chunk-graph cleanup and (2) the interop init-target view. The strict analysis and code generation that consume the deferred bookkeeping come in later layers.
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## [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]>
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What this does (and doesn't). Under
output.strictExecutionOrder, skip the "safely merge CJS namespace" optimization:determine_safely_merge_cjs_nsnow early-returns when strict execution order is enabled. This is the one piece of strict-gated link-stage groundwork that stands on its own. It does NOT change flag-off behavior, and it deliberately excludes the feature's other strict bookkeeping (star_export_record_by_name,execution_dependencies, star-reexport path recording) because none of it has a reader in this PR — that lands with the analysis that consumes it.Why. The optimization lets several ESM importers of the same CommonJS module share one namespace binding, which relocates the surviving
require()to whichever importer statement stays included. That reordering can move a CommonJS module's evaluation past statements that should run after it — an execution-order break that no amount of wrapping can repair. Under strict execution order, correctness must win over the small byte saving, so we keep each importer's own call site (the CJS wrapper memoizes, so the module still evaluates exactly once). The addedcjs_ns_merge_skippedfixture shows the contrast directly: the default variant shares oneimport_cjs, while the strict variant giveslib.jsandmain.jstheir own bindings materialized at their own use sites.Validation.
cargo test -p rolldown --test integration: passing (same 5 pre-existing environment-only failures as the rest of the stack).cargo clippy -p rolldown --all-targets -- -D warningsis clean andcargo fmt --allproduces no diff. Flag-off output is byte-identical — no non-strict snapshot changed. Exactly one existing strict-only snapshot changed,react-like: the sharedimport_commonjs = __toESM(require_commonjs())is now split solib.jsdoes a barerequire_commonjs()andmain.jsmaterializes the namespace at its own use site. That is the intended strict-only correctness improvement.Stack. Top of a three-layer stack slicing the
output.strictExecutionOrderwork; builds on (1) wrap-kind / chunk-graph cleanup and (2) the interop init-target view. The strict analysis and code generation that consume the deferred bookkeeping come in later layers.