refactor: move chunk merging code out of code_splitting.rs by IWANABETHATGUY · Pull Request #7285 · rolldown/rolldown

IWANABETHATGUY · 2025-12-01T07:56:49Z

IWANABETHATGUY · 2025-12-01T07:57:04Z

refactor: move chunk merging code out of code_splitting.rs #7285 👈 (View in Graphite)
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IWANABETHATGUY · 2025-12-01T08:12:09Z

The chunk optimizer is already opt-in

rolldown/crates/rolldown/src/stages/generate_stage/code_splitting.rs

Lines 797 to 806 in 1a4a8b2

    
           if allow_extension_optimize { 
        
             self.try_insert_common_module_to_exist_chunk( 
        
               chunk_graph, 
        
               bits_to_chunk, 
        
               input_base, 
        
               pending_common_chunks, 
        
               &self.link_output.module_table, 
        
             ); 
        
           } 
        
           Ok(())

Copilot

Pull request overview

This PR refactors chunk merging optimization logic by extracting it from code_splitting.rs into a dedicated chunk_optimizer.rs module. The refactoring improves code organization by separating chunk optimization concerns from the main code splitting logic, making the codebase more modular and easier to maintain.

Key Changes:

Created new chunk_optimizer.rs module containing chunk merging optimization functions
Moved try_insert_into_exists_chunk, collect_entry_modules, and find_merge_target from GenerateStage methods to standalone functions
Updated imports and function calls in code_splitting.rs to use the new module

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
`crates/rolldown/src/stages/generate_stage/mod.rs`	Added module declaration for the new `chunk_optimizer` module
`crates/rolldown/src/stages/generate_stage/code_splitting.rs`	Removed chunk merging methods and added import for the extracted functionality
`crates/rolldown/src/stages/generate_stage/chunk_optimizer.rs`	New module containing chunk optimization logic with public `try_insert_into_exists_chunk` function and helper functions

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crates/rolldown/src/stages/generate_stage/chunk_optimizer.rs

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Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

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crates/rolldown/src/stages/generate_stage/code_splitting.rs

crates/rolldown/src/stages/generate_stage/chunk_optimizer.rs

crates/rolldown/src/stages/generate_stage/code_splitting.rs

github-actions · 2025-12-01T08:34:45Z

Benchmarks Rust

target: main(5ef49ad)
pr: 12-01-refactor_move_chunk_merging_code_out_of_code_splitting.rs(0ce4a17)

group                                                        pr                                     target
-----                                                        --                                     ------
bundle/bundle@multi-duplicated-top-level-symbol              1.06     65.7±2.10ms        ? ?/sec    1.00     62.1±1.55ms        ? ?/sec
bundle/bundle@multi-duplicated-top-level-symbol-sourcemap    1.06     73.3±2.91ms        ? ?/sec    1.00     69.2±2.61ms        ? ?/sec
bundle/bundle@rome_ts                                        1.02    107.6±3.13ms        ? ?/sec    1.00    105.4±1.82ms        ? ?/sec
bundle/bundle@rome_ts-sourcemap                              1.02    120.7±2.31ms        ? ?/sec    1.00    118.1±1.80ms        ? ?/sec
bundle/bundle@threejs                                        1.01     38.9±0.66ms        ? ?/sec    1.00     38.7±1.48ms        ? ?/sec
bundle/bundle@threejs-sourcemap                              1.02     43.2±1.08ms        ? ?/sec    1.00     42.4±1.05ms        ? ?/sec
bundle/bundle@threejs10x                                     1.01    390.8±5.36ms        ? ?/sec    1.00    385.5±5.01ms        ? ?/sec
bundle/bundle@threejs10x-sourcemap                           1.01    448.9±5.30ms        ? ?/sec    1.00    445.2±4.00ms        ? ?/sec
scan/scan@rome_ts                                            1.00     84.4±1.88ms        ? ?/sec    1.00     84.4±1.75ms        ? ?/sec
scan/scan@threejs                                            1.02     29.0±1.59ms        ? ?/sec    1.00     28.5±0.49ms        ? ?/sec
scan/scan@threejs10x                                         1.01    295.8±4.15ms        ? ?/sec    1.00    294.3±3.80ms        ? ?/sec

graphite-app · 2025-12-01T13:04:45Z

Merge activity

Dec 1, 1:04 PM UTC: IWANABETHATGUY added this pull request to the Graphite merge queue.
Dec 1, 1:20 PM UTC: Merged by the Graphite merge queue.

Closed #7282

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@sapphi-red

## [1.0.0-beta.53] - 2025-12-03 💥 Breaking Changes - Drop `i686-pc-windows-msvc` target support 🚀 Chunk Merging Optimization - Rolldown now automatically merges shared chunks when entries import each other (when `preserveEntrySignature` is not `strict`) ```shell Before: entry.js → imports → shared.js (common chunk) entry2.js → imports → shared.js Output: 3 chunks (entry.js, entry2.js, shared.js) After: entry.js → contains shared code entry2.js → imports → entry.js Output: 2 chunks (entry.js, entry2.js) ``` ### 💥 BREAKING CHANGES - drop `i686-pc-windows-msvc` target support (#7230) by @sapphi-red ### 🚀 Features - rolldown_plugin_vite_manifest: pass normalized options to `isLegacy` callback (#7321) by @shulaoda - plugin/vite-resolve: add `disableCache` option (#6763) by @sapphi-red - rolldown: export `createTokioRuntime` for tsdown (#7264) by @shulaoda - rolldown_plugin_vite_html: sync `moduleSideEffects` for already loaded modules (#7254) by @shulaoda - rolldown_plugin_vite_html: load module scripts with side effects to prevent tree-shaking (#7244) by @shulaoda - rolldown_plugin_vite_css_post: implement `cssScopeTo` for scoped CSS tree-shaking (#7240) by @shulaoda ### 🐛 Bug Fixes - export default class decl __name runtime insertion (#7316) by @IWANABETHATGUY - chunk side effects calculation (#7273) by @IWANABETHATGUY - node: `output.generateCode.preset: 'es2015'` should set `output.generateCode.symbols: true` by default (#7314) by @sapphi-red - skip name helper for classes with static name property (#7312) by @IWANABETHATGUY - preserve chunk imports relationship after chunk merging (#7303) by @shulaoda - dev: make `register_modules` async (#7289) by @hyf0 - preserve computed property in object destructuring (#7288) by @IWANABETHATGUY - support dynamic imports with shared dependencies (#7261) by @IWANABETHATGUY - call `defer_sync_scan_data` in non-incremental build mode (#7255) by @shulaoda - optimize chunk merging for shared entry points (#7194) by @IWANABETHATGUY - add indentation for UMD format output (#7263) by @IWANABETHATGUY - rolldown_plugin_vite_css_post: pass options to `isLegacy` callback for proper legacy detection (#7260) by @shulaoda - rolldown_plugin_vite_css_post: also detect `?inline=true` query for inlined CSS (#7245) by @shulaoda - rolldown_plugin_vite_css_post: distinguish empty CSS from no CSS (#7241) by @shulaoda - add Windows support for t-run command (#7242) by @IWANABETHATGUY - cjs: prevent duplicate require declarations for external modules with preserveModules (#7234) by @logaretm - rolldown_plugin_vite_resolve: resolve from root for virtual modules (#7236) by @sapphi-red - include entry level external modules in chunk exports (#7218) by @IWANABETHATGUY ### 🚜 Refactor - dev: make `removeClient` async (#7313) by @hyf0 - move chunk merging code out of code_splitting.rs (#7285) by @IWANABETHATGUY - extract common function util for chunk merging (#7271) by @IWANABETHATGUY - use iterative method to merge chunks (#7256) by @IWANABETHATGUY - use concat_string! instead of string replace for generating chunk level exports (#7247) by @IWANABETHATGUY ### 📚 Documentation - add warning to experimental.resolveNewUrlToAsset about JS/TS files (#7300) by @Copilot - add sequential hook execution difference in plugin-api.md (#7308) by @Copilot - add migration example from onwarn to onLog (#7299) by @Copilot - add migration example for manualChunks to advancedChunks (#7298) by @Copilot - deps: bump vitepress to fix build (#7307) by @sapphi-red - examples & text for experimental.resolveNewUrlToAsset (#7259) by @TheAlexLichter ### ⚡ Performance - rolldown_plugin_vite_css_post: lazily load `cssScopeTo` from JS module options (#7253) by @shulaoda - rolldown_plugin_vite_css_post: avoid unnecessary string clones in `resolve_asset_urls_in_css` (#7250) by @shulaoda ### 🧪 Testing - generate relative path like name in advanced chunks (#7267) by @IWANABETHATGUY - add test case for preserveEntrySignatures with re-exports (#7279) by @IWANABETHATGUY - add test262 integration tests (#7196) by @sapphi-red ### ⚙️ Miscellaneous Tasks - deps: update dependency rolldown-plugin-dts to v0.18.1 (#7304) by @renovate[bot] - enable tracing feature for napi (#7322) by @sapphi-red - deps: update napi (#7320) by @renovate[bot] - deps: update oxc (#7318) by @renovate[bot] - deps: update napi (#7317) by @renovate[bot] - deps: update oxc to v0.100.0 (#7301) by @renovate[bot] - deps: downgrade pnpm to 10.23.0 to fix Netlify build (#7306) by @shulaoda - add `trustPolicyExclude` for chokidar and semver (#7302) by @sapphi-red - update pnpm lockfile (#7291) by @IWANABETHATGUY - deps: update npm packages (#7272) by @renovate[bot] - deps: update rust crates (#7270) by @renovate[bot] - deps: update oxc (#7262) by @renovate[bot] - deps: update github-actions (#7269) by @renovate[bot] - deps: update dependency dprint-typescript to v0.95.13 (#7268) by @renovate[bot] - deps: update `html5gum` to 0.8.1 (#7265) by @shulaoda - rolldown: remove unused `getModuleOptions` from `PluginContext` (#7266) by @shulaoda - remove unnecessary justfile ignore (#7243) by @IWANABETHATGUY - deps: update oxc apps (#7238) by @renovate[bot] - add `nul` to workaround https://github.com/anthropics/claude-c… (#7237) by @IWANABETHATGUY - deps: update dependency valibot to v1.2.0 [security] (#7231) by @renovate[bot] - deps: update crate-ci/typos action to v1.40.0 (#7232) by @renovate[bot] ### ❤️ New Contributors * @logaretm made their first contribution in [#7234](#7234) Co-authored-by: shulaoda <[email protected]>

github-actions bot assigned IWANABETHATGUY Dec 1, 2025

IWANABETHATGUY marked this pull request as ready for review December 1, 2025 08:10

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IWANABETHATGUY force-pushed the 12-01-refactor_move_chunk_merging_code_out_of_code_splitting.rs branch from 32ec90d to 1a4a8b2 Compare December 1, 2025 08:10

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IWANABETHATGUY force-pushed the 12-01-refactor_move_chunk_merging_code_out_of_code_splitting.rs branch from fc0ad25 to dcbcde4 Compare December 1, 2025 08:19

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fix: preserve computed property in object destructuring #7288

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refactor: move chunk merging code out of code_splitting.rs (#7285)

0ce4a17

Closed #7282

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graphite-app bot deleted the 12-01-refactor_move_chunk_merging_code_out_of_code_splitting.rs branch December 1, 2025 13:20

This was referenced Dec 3, 2025

release: v1.0.0-beta.53 #7319

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release: v1.0.0-beta.53 #7324

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