feat(mcs): support `entriesAware` by hyf0 · Pull Request #8274 · rolldown/rolldown

hyf0 · 2026-02-11T08:36:53Z

Fixes [AdvancedChunks] Compute module groups with considering the import relationships #7117 in a rolldown-style, which means considering the fact that rolldown enforcing esm and singleton.
MCS -> Manual Code Splitting

What `entriesAware` does

Without entriesAware (default false):
All modules matching a group are merged into one chunk. Every entry that imports any of these modules must load the entire chunk — even modules it doesn't need.

With entriesAware: true:
Modules are sub-grouped by their entry-point reachability (which entries can reach them). Modules shared by the same set of entries go into the same chunk; modules shared by a different set go into a separate chunk.

Concrete example

Three entries: entry-a, entry-b, entry-c. One group: { name: "vendor", test: "shared-by", entriesAware: true }.

Modules:

shared-by-abc — imported by A, B, C
shared-by-ab — imported by A, B only
shared-by-a — imported by A only

entriesAware: false → 1 chunk:

vendor.js contains all three modules. All three entries import vendor.js, so entry-c loads shared-by-ab and shared-by-a unnecessarily.

entriesAware: true → 3 chunks:

vendor.js (shared-by-abc, reachable by A+B+C) — loaded by all entries
vendor2.js (shared-by-ab, reachable by A+B) — loaded by entry-a and entry-b only
vendor3.js (shared-by-a, reachable by A) — loaded by entry-a only

Each entry only loads exactly the code it needs.

Interaction with `maxSize`

maxSize splitting happens after entriesAware grouping. The pipeline is:

Group modules by match pattern + (if entriesAware) entry-reachability bits
Filter groups by minSize / minShareCount
Split any group exceeding maxSize into smaller sub-chunks using a two-pointer greedy algorithm (sorted by module size, split so both halves satisfy minSize)
Create final chunks

So with entriesAware: true, maxSize applies to each reachability-based sub-group independently. A group that was already split by entry reachability may be further split if it still exceeds maxSize.

Interaction with `minShareCount`

When combined with entriesAware: true, minShareCount filters based on how many entries reach each individual module. Example from tests:

Group { name: "utils", test: "utils", minShareCount: 2, entriesAware: true }
formatDate (shared by A, B → count=2) → goes into utils.js
deepClone (shared by B, C → count=2) → goes into utils2.js (different reachability set)
debounce (only used by A → count=1) → not captured by the group, stays inlined in entry-a

hyf0 · 2026-02-11T08:37:08Z

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Copilot

Pull request overview

This PR adds support for the entriesAware option in manual code splitting (also known as advanced chunks), which enables more granular chunk splitting based on which entry points actually import specific modules. This addresses issue #7117 regarding computation of module groups with import relationships.

Changes:

Added entriesAware boolean option to CodeSplittingGroup configuration, allowing modules to be split by entry-point reachability
Updated chunk creation debug info to display which entries reference each chunk when entriesAware is enabled
Added comprehensive test coverage with three test scenarios demonstrating different behaviors

Reviewed changes

Copilot reviewed 35 out of 35 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/rolldown/src/utils/validator.ts	Added schema validation for new `entriesAware` field
packages/rolldown/src/options/output-options.ts	Added comprehensive documentation and type definition for `entriesAware` option
packages/rolldown/src/binding.d.cts	Updated TypeScript binding interface to include `entriesAware`
crates/rolldown_utils/src/bitset.rs	Minor formatting improvement (added blank line)
crates/rolldown_testing/_config.schema.json	Added JSON schema for `entriesAware` in test configs
crates/rolldown_common/src/inner_bundler_options/types/manual_code_splitting_options.rs	Added `entries_aware` field to `MatchGroup` struct
crates/rolldown_binding/src/utils/normalize_binding_options.rs	Forwarded `entries_aware` from binding to internal options
crates/rolldown_binding/src/options/binding_output_options/binding_manual_code_splitting_options.rs	Added `entries_aware` field to binding struct
crates/rolldown/tests/snapshots/integration_rolldown__filename_with_hash.snap	Updated snapshot with new test outputs
crates/rolldown/tests/rolldown/function/advanced_chunks/entries_aware_true/*	Test case demonstrating `entriesAware: true` with multiple vendor chunks
crates/rolldown/tests/rolldown/function/advanced_chunks/entries_aware_min_share_count/*	Test case combining `entriesAware: true` with `minShareCount`
crates/rolldown/tests/rolldown/function/advanced_chunks/entries_aware_false/*	Test case demonstrating default behavior (`entriesAware: false`)
crates/rolldown/src/stages/generate_stage/manual_code_splitting.rs	Core implementation using BitSet as part of unique key when `entriesAware` is enabled
crates/rolldown/src/stages/generate_stage/chunk_ext.rs	Refactored `ChunkCreationReason` to include entry information and extracted helper function

github-actions · 2026-02-11T08:53:30Z

Benchmarks Rust

target: main(179df16)
pr: 02-11-feat_mcs_support_entriesaware_(9fa5363)

group                                                        pr                                     target
-----                                                        --                                     ------
bundle/bundle@multi-duplicated-top-level-symbol              1.00     74.8±2.48ms        ? ?/sec    1.01     75.5±1.97ms        ? ?/sec
bundle/bundle@multi-duplicated-top-level-symbol-sourcemap    1.00     80.6±2.27ms        ? ?/sec    1.02     82.2±1.87ms        ? ?/sec
bundle/bundle@rome_ts                                        1.00    104.3±3.08ms        ? ?/sec    1.00    103.9±1.88ms        ? ?/sec
bundle/bundle@rome_ts-sourcemap                              1.00    115.0±1.64ms        ? ?/sec    1.01    116.5±2.01ms        ? ?/sec
bundle/bundle@threejs                                        1.02     38.2±2.39ms        ? ?/sec    1.00     37.6±2.00ms        ? ?/sec
bundle/bundle@threejs-sourcemap                              1.00     42.4±0.70ms        ? ?/sec    1.00     42.6±0.67ms        ? ?/sec
bundle/bundle@threejs10x                                     1.00    376.5±5.11ms        ? ?/sec    1.01    380.1±3.92ms        ? ?/sec
bundle/bundle@threejs10x-sourcemap                           1.00    432.8±6.17ms        ? ?/sec    1.01    436.7±9.12ms        ? ?/sec
scan/scan@rome_ts                                            1.02     82.0±1.65ms        ? ?/sec    1.00     80.8±1.79ms        ? ?/sec
scan/scan@threejs                                            1.03     28.7±1.81ms        ? ?/sec    1.00     27.8±0.43ms        ? ?/sec
scan/scan@threejs10x                                         1.00    287.3±4.70ms        ? ?/sec    1.00    286.5±5.03ms        ? ?/sec

graphite-app · 2026-02-11T12:24:39Z

Merge activity

Feb 11, 12:24 PM UTC: hyf0 added this pull request to the Graphite merge queue.
Feb 11, 12:36 PM UTC: Merged by the Graphite merge queue.

- Fixes #7117 in a rolldown-style, which means considering the fact that rolldown enforcing esm and singleton. - MCS -> Manual Code Splitting --- ## What `entriesAware` does **Without `entriesAware` (default `false`):** All modules matching a group are merged into one chunk. Every entry that imports any of these modules must load the entire chunk — even modules it doesn't need. **With `entriesAware: true`:** Modules are sub-grouped by their entry-point reachability (which entries can reach them). Modules shared by the **same set** of entries go into the same chunk; modules shared by a **different set** go into a separate chunk. ## Concrete example Three entries: `entry-a`, `entry-b`, `entry-c`. One group: `{ name: "vendor", test: "shared-by", entriesAware: true }`. Modules: - `shared-by-abc` — imported by A, B, C - `shared-by-ab` — imported by A, B only - `shared-by-a` — imported by A only **`entriesAware: false`** → 1 chunk: - `vendor.js` contains all three modules. All three entries import `vendor.js`, so entry-c loads `shared-by-ab` and `shared-by-a` unnecessarily. **`entriesAware: true`** → 3 chunks: - `vendor.js` (`shared-by-abc`, reachable by A+B+C) — loaded by all entries - `vendor2.js` (`shared-by-ab`, reachable by A+B) — loaded by entry-a and entry-b only - `vendor3.js` (`shared-by-a`, reachable by A) — loaded by entry-a only Each entry only loads exactly the code it needs. ## Interaction with `maxSize` `maxSize` splitting happens **after** `entriesAware` grouping. The pipeline is: 1. **Group** modules by match pattern + (if `entriesAware`) entry-reachability bits 2. **Filter** groups by `minSize` / `minShareCount` 3. **Split** any group exceeding `maxSize` into smaller sub-chunks using a two-pointer greedy algorithm (sorted by module size, split so both halves satisfy `minSize`) 4. **Create** final chunks So with `entriesAware: true`, `maxSize` applies to each reachability-based sub-group independently. A group that was already split by entry reachability may be further split if it still exceeds `maxSize`. ## Interaction with `minShareCount` When combined with `entriesAware: true`, `minShareCount` filters based on how many entries reach each individual module. Example from tests: - Group `{ name: "utils", test: "utils", minShareCount: 2, entriesAware: true }` - `formatDate` (shared by A, B → count=2) → goes into `utils.js` - `deepClone` (shared by B, C → count=2) → goes into `utils2.js` (different reachability set) - `debounce` (only used by A → count=1) → **not captured** by the group, stays inlined in entry-a

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@sapphi-red

## [1.0.0-rc.5] - 2026-02-18 💡 Smarter `entriesAware` Manual Code Splitting New `entriesAware` and `entriesAwareMergeThreshold` options for `manualCodeSplitting.groups[]` enable entry-reachability-based chunk splitting with automatic small chunk merging. - `entriesAware: true` splits matched modules by entry reachability — modules reached by the same set of entries are grouped together, providing the most precise loading behavior with less over-fetching - Chunks now get more readable names reflecting their entry associations (e.g. `vendor-entry-a-entry-b.js`) instead of opaque hashes - `entriesAwareMergeThreshold` sets a byte-size threshold to merge tiny subgroups into the closest sibling with the fewest extra entries, reducing micro-chunk fragmentation while preserving precision - Recommended to use together with `maxSize`: merge tiny chunks first to reduce request overhead, then cap large chunks to control payload size ```js manualCodeSplitting: { groups: [{ name: 'vendor', test: /node_modules/, entriesAware: true, entriesAwareMergeThreshold: 28000, // bytes }] } ``` ### 🚀 Features - add `Visitor` to `rolldown/utils` (#8373) by @sapphi-red - module-info: add `inputFormat` property to `ModuleInfo` (#8329) by @shulaoda - default `treeshake.invalid_import_side_effects` to `false` (#8357) by @sapphi-red - rolldown_utils: add `IndexBitSet` (#8343) by @sapphi-red - rolldown_utils: add more methods and trait impls to BitSet (#8342) by @sapphi-red - rolldown_plugin_vite_build_import_analysis: add support for `await import().then((m) => m.prop)` (#8328) by @sapphi-red - rolldown_plugin_vite_reporter: support custom logger for build infos (#7652) by @shulaoda - rust/mcs: support `entriesAwareMergeThreshold` (#8312) by @hyf0 - mcs: `maxSize` will split the oversized chunk with taking file relevance into account (#8277) by @hyf0 - rolldown_plugin_vite_import_glob: support template literal in glob import patterns (#8298) by @shulaoda - rolldown_plugin_chunk_import_map: output importmap without spaces (#8297) by @sapphi-red - add INEFFECTIVE_DYNAMIC_IMPORT warning in core (#8284) by @shulaoda - mcs: generate more readable name for `entriesAware` chunks (#8275) by @hyf0 - mcs: support `entriesAware` (#8274) by @hyf0 ### 🐛 Bug Fixes - improve circular dependency detection in chunk optimizer (#8371) by @IWANABETHATGUY - align `minify.compress: true` and `minify.mangle: true` with `minify: true` (#8367) by @sapphi-red - rolldown_plugin_esm_external_require: apply conversion to UMD and IIFE outputs (#8359) by @sapphi-red - cjs: bailout treeshaking on cjs modules that have multiple re-exports (#8348) by @hyf0 - handle member expression and this expression in JSX element name rewriting (#8323) by @IWANABETHATGUY - pad `encode_hash_with_base` output to fixed length to prevent slice panics (#8320) by @shulaoda - `xxhash_with_base` skips hashing when input is exactly 16 bytes (#8319) by @shulaoda - complete `ImportKind::try_from` with missing variants and correct `url-import` to `url-token` (#8310) by @shulaoda - mark Node.js builtin modules as side-effect-free when resolved via `external` config (#8304) by @IWANABETHATGUY - mcs: `maxSize` should split chunks correctly based on sizes (#8289) by @hyf0 ### 🚜 Refactor - introduce `RawMangleOptions` and `RawCompressOptions` (#8366) by @sapphi-red - mcs: refactor `apply_manual_code_splitting` into `ManualSplitter` (#8346) by @hyf0 - rolldown_plugin_vite_reporter: simplify hook registration and remove redundant state (#8322) by @shulaoda - use set to store user defined entry modules (#8315) by @IWANABETHATGUY - rust/mcs: collect groups into map at first for having clean and performant operations (#8313) by @hyf0 - mcs: introduce newtype `ModuleGroupOrigin` and `ModuleGroupId` (#8311) by @hyf0 - remove unnecessary `FinalizerMutableState` struct (#8303) by @shulaoda - move module finalization into `finalize_modules` (#8302) by @shulaoda - extract `apply_transfer_parts_mutation` into its own module (#8301) by @shulaoda - move ESM format check into `determine_export_mode` (#8294) by @shulaoda - remove `warnings` field from `GenerateContext` (#8293) by @shulaoda - extract util function remove clippy supression (#8290) by @IWANABETHATGUY - move `is_in_node_modules` to `PathExt` trait in `rolldown_std_utils` (#8286) by @shulaoda - rolldown_plugin_vite_reporter: remove unnecessary ineffective dynamic import detection logic (#8285) by @shulaoda - dev: inject hmr runtime to `\0rolldown/runtime.js` (#8234) by @hyf0 - improve naming in chunk_optimizer (#8287) by @IWANABETHATGUY - simplify PostChunkOptimizationOperation from bitflags to enum (#8283) by @IWANABETHATGUY - optimize BitSet.index_of_one to return iterator instead of Vec (#8282) by @IWANABETHATGUY ### 📚 Documentation - change default value in `format` JSDoc from `'esm'` to `'es'` (#8372) by @shulaoda - in-depth: remove `invalidImportSideEffects` option mention from lazy barrel optimization doc (#8355) by @sapphi-red - mcs: clarify `minSize` constraints (#8279) by @ShroXd ### ⚡ Performance - use IndexVec for chunk TLA detection (#8341) by @sapphi-red - only invoke single resolve call for the same specifier and import kind (#8332) by @sapphi-red - rolldown_plugin_vite_reporter: skip gzip computation when `report_compressed_size` is disabled (#8321) by @shulaoda ### 🧪 Testing - use `vi.waitFor` and `expect.poll` instead of custom `waitUtil` function (#8369) by @sapphi-red - rolldown_plugin_esm_external_require_plugin: add tests (#8358) by @sapphi-red - add watch file tests (#8330) by @sapphi-red - rolldown_plugin_vite_build_import_analysis: add test for dynamic import treeshaking (#8327) by @sapphi-red ### ⚙️ Miscellaneous Tasks - prepare-release: skip workflow on forked repositories (#8368) by @shulaoda - format more files (#8360) by @sapphi-red - deps: update oxc to v0.114.0 (#8347) by @camc314 - deps: update test262 submodule for tests (#8354) by @sapphi-red - deps: update crate-ci/typos action to v1.43.5 (#8350) by @renovate[bot] - deps: update oxc apps (#8351) by @renovate[bot] - rolldown_plugin_vite_reporter: remove unnecessary README.md (#8334) by @shulaoda - deps: update npm packages (#8338) by @renovate[bot] - deps: update rust crates (#8339) by @renovate[bot] - deps: update dependency oxlint-tsgolint to v0.13.0 (#8337) by @renovate[bot] - deps: update github-actions (#8336) by @renovate[bot] - deps: update napi to v3.8.3 (#8331) by @renovate[bot] - deps: update dependency oxlint-tsgolint to v0.12.2 (#8325) by @renovate[bot] - remove unnecessary transform.decorator (#8314) by @IWANABETHATGUY - deps: update dependency rust to v1.93.1 (#8305) by @renovate[bot] - deps: update dependency oxlint-tsgolint to v0.12.1 (#8300) by @renovate[bot] - deps: update oxc apps (#8296) by @renovate[bot] - docs: don't skip for build runs without cache (#8281) by @sapphi-red

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feat(mcs): generate more readable name for entriesAware chunks #8275

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hyf0 force-pushed the 02-11-feat_mcs_support_entriesaware_ branch from b6861b0 to 94aa580 Compare February 11, 2026 10:31

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feat(mcs): maxSize will split the oversized chunk with taking file relevance into account #8277

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feat(mcs): support `entriesAware`#8274

feat(mcs): support `entriesAware`#8274
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What entriesAware does

Concrete example

Interaction with maxSize

Interaction with minShareCount

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hyf0 commented Feb 11, 2026 •

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What `entriesAware` does

Interaction with `maxSize`

Interaction with `minShareCount`

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