feat(option): add experimental option to control chunk optimization by IWANABETHATGUY · Pull Request #7738 · rolldown/rolldown

IWANABETHATGUY · 2026-01-03T05:48:01Z

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IWANABETHATGUY · 2026-01-03T05:48:27Z

feat(option): add experimental option to control chunk optimization #7738 👈 (View in Graphite)
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Copilot

Pull request overview

This PR adds an experimental option optimizeChunks to control chunk optimization behavior in rolldown. The option allows disabling an optimization where entry chunks can have different exports than the underlying entry module, which helps reduce the number of generated chunks when enabled.

Key changes:

Adds optimizeChunks experimental option with a default value of true (enabled by default)
Implements the option across TypeScript/JavaScript and Rust layers
Updates chunk generation logic to respect this option when determining whether to optimize chunks
Adds test coverage with a config variant to test the behavior when the optimization is disabled

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 5 comments.

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File	Description
`packages/rolldown/src/options/input-options.ts`	Adds TypeScript interface and comprehensive documentation for the `optimizeChunks` option
`packages/rolldown/src/utils/validator.ts`	Adds validation schema for the new experimental option
`packages/rolldown/src/utils/bindingify-input-options.ts`	Passes the option from TypeScript to Rust binding layer
`packages/rolldown/src/binding.d.cts`	Adds TypeScript type definition for the binding interface
`crates/rolldown_common/src/inner_bundler_options/types/experimental_options.rs`	Defines the Rust option field and helper method with default value
`crates/rolldown_binding/src/options/binding_input_options/binding_experimental_options.rs`	Implements conversion from binding layer to internal Rust types
`crates/rolldown/src/stages/generate_stage/code_splitting.rs`	Integrates the option into chunk optimization logic, gating both common chunk insertion and facade optimization
`crates/rolldown_testing_config/src/config_variant.rs`	Adds test configuration support for the option (with naming inconsistency)
`crates/rolldown_testing/_config.schema.json`	Updates JSON schema for test configurations (with naming inconsistency)
`crates/rolldown/tests/rolldown/code_splitting/issue_5276/_config.json`	Adds test variant to verify behavior when optimization is disabled (with naming inconsistency)
`crates/rolldown/tests/rolldown/code_splitting/issue_5276/main.js`	Updates test assertions to handle facade chunk module exports correctly
`crates/rolldown/tests/rolldown/code_splitting/issue_5276/artifacts.snap`	Updates snapshot with new test variant output
`crates/rolldown/tests/snapshots/integration_rolldown__filename_with_hash.snap`	Updates hash snapshot due to code changes

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crates/rolldown_testing_config/src/config_variant.rs

crates/rolldown_testing/_config.schema.json

crates/rolldown_testing_config/src/config_variant.rs

crates/rolldown/tests/rolldown/code_splitting/issue_5276/_config.json

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commit: d53a538

github-actions · 2026-01-03T06:19:24Z

Benchmarks Rust

target: main(2ee2b1c)
pr: 01-03-add_new_option_to_opt_out_chunk_optimization(d2a77eb)

group                                                        pr                                     target
-----                                                        --                                     ------
bundle/bundle@multi-duplicated-top-level-symbol              1.00     62.3±1.53ms        ? ?/sec    1.02     63.5±2.08ms        ? ?/sec
bundle/bundle@multi-duplicated-top-level-symbol-sourcemap    1.00     68.7±1.70ms        ? ?/sec    1.01     69.4±1.82ms        ? ?/sec
bundle/bundle@rome_ts                                        1.00    106.8±2.87ms        ? ?/sec    1.00    106.8±1.71ms        ? ?/sec
bundle/bundle@rome_ts-sourcemap                              1.00    117.3±1.69ms        ? ?/sec    1.00    117.7±1.64ms        ? ?/sec
bundle/bundle@threejs                                        1.00     38.2±2.08ms        ? ?/sec    1.00     38.4±2.16ms        ? ?/sec
bundle/bundle@threejs-sourcemap                              1.01     43.1±1.07ms        ? ?/sec    1.00     42.6±0.65ms        ? ?/sec
bundle/bundle@threejs10x                                     1.00    386.9±3.50ms        ? ?/sec    1.01    390.7±7.16ms        ? ?/sec
bundle/bundle@threejs10x-sourcemap                           1.00    446.8±4.44ms        ? ?/sec    1.02    453.9±7.34ms        ? ?/sec
scan/scan@rome_ts                                            1.00     85.4±2.11ms        ? ?/sec    1.01     85.9±1.92ms        ? ?/sec
scan/scan@threejs                                            1.00     29.2±1.60ms        ? ?/sec    1.03     30.2±2.36ms        ? ?/sec
scan/scan@threejs10x                                         1.00    296.4±4.83ms        ? ?/sec    1.00    297.8±5.57ms        ? ?/sec

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

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

graphite-app · 2026-01-03T16:29:01Z

Merge activity

Jan 3, 4:29 PM UTC: IWANABETHATGUY added this pull request to the Graphite merge queue.
Jan 3, 4:39 PM UTC: Merged by the Graphite merge queue.

…7738)

@shulaoda

## [1.0.0-beta.59] - 2026-01-07 ⚡ Inline Dynamic Imports for Statically Imported Modules - When a module is already statically imported, dynamic imports to that same module are now inlined instead of creating a separate chunk ### 🚀 Features - plugin_timings: add 3s threshold and doc link to warning message (#7741) by @shulaoda - improve treeshaking logic to handle empty parameter list in dynamic import .then() callbacks (#7781) by @Copilot - dev/lazy: don't include already executed modules (#7745) by @hyf0 - dev/lazy: support dynamic `import(..)` (#7726) by @hyf0 - inline dynamic imports that imports statically imported modules (#7742) by @IWANABETHATGUY - option: add experimental option to control chunk optimization (#7738) by @IWANABETHATGUY ### 🐛 Bug Fixes - inline dynamic entry to user defined entry with esm wrap kind (#7783) by @IWANABETHATGUY - use canonical namespace reference for property access (#7777) by @IWANABETHATGUY - dynamic entry merged into common chunk with cjs and esm wrap kind (#7771) by @IWANABETHATGUY - tla: should not await non-tla-related modules (#7768) by @hyf0 - dynamic entry captured by common chunk with CJS format (#7757) by @IWANABETHATGUY - module_loader: mark emitted chunks as user-defined entry when already loaded (#7765) by @shulaoda - normalize preserveModulesRoot path (#7737) by @IWANABETHATGUY - linker: resolve race condition in side effects computation for export-star (#7728) by @camc314 ### 🚜 Refactor - plugin_timings: filter out plugins with duration < 1s from timing warnings (#7785) by @shulaoda - module_loader: remove unnecessary collect before extend (#7769) by @shulaoda - rename _id suffixes to _idx for oxc_index types (#7767) by @IWANABETHATGUY - remove duplicate `preserve_entry_signatures` from `AddEntryModuleMsg` (#7762) by @shulaoda - module_loader: pass `user_defined_entries` by reference (#7756) by @shulaoda - dev/lazy: get proxy entry's `ResolvedId` correctly (#7746) by @hyf0 - simplify try_rewrite_import_expression control flow (#7753) by @IWANABETHATGUY - module_loader: remove unnecessary dynamic import handling for runtime module (#7754) by @shulaoda - inline __toDynamicImportESM (#7747) by @IWANABETHATGUY - use From impl for ModuleLoaderOutput conversion (#7732) by @shulaoda - remove duplicate fields from `ModuleLoader` (#7731) by @shulaoda - tweak `resolve_user_defined_entries` (#7727) by @shulaoda ### 📚 Documentation - add rolldown-string reference to native MagicString compatibility section (#7778) by @Copilot - improve comments for export star side effects handling (#7730) by @IWANABETHATGUY ### 🧪 Testing - use assertion instead of console.log for some testcase (#7744) by @IWANABETHATGUY ### ⚙️ Miscellaneous Tasks - tweak some `output.dynamicImportInCjs` related rollup test results (#7776) by @sapphi-red - mark esbuild/dce/dce_of_symbol_ctor_call as passed (#7775) by @sapphi-red - deps: update oxc apps (#7772) by @renovate[bot] - vite-tests: allow running on PRs with `test: vite-tests` label (#7770) by @shulaoda - deps: update oxc apps (#7760) by @renovate[bot] - deps: update rollup submodule for tests to v4.55.1 (#7763) by @sapphi-red - deps: update test262 submodule for tests (#7764) by @sapphi-red - deps: update oxc to v0.107.0 (#7758) by @camc314 - deps: update taiki-e/install-action action to v2.65.13 (#7751) by @renovate[bot] - deps: update rust crates (#7750) by @renovate[bot] - deps: update npm packages (#7749) by @renovate[bot] - deps: update github-actions (#7748) by @renovate[bot] - deps: update dependency oxlint-tsgolint to v0.10.1 (#7729) by @renovate[bot] - deps: update crate-ci/typos action to v1.41.0 (#7725) by @renovate[bot] Co-authored-by: shulaoda <[email protected]>

github-actions bot assigned IWANABETHATGUY Jan 3, 2026

IWANABETHATGUY changed the title ~~add new option to opt out chunk optimization~~ feat: add experimental option to control chunk optimization Jan 3, 2026

IWANABETHATGUY marked this pull request as ready for review January 3, 2026 06:03

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IWANABETHATGUY changed the title ~~feat: add experimental option to control chunk optimization~~ feat(option): add experimental option to control chunk optimization Jan 3, 2026

feat(option): add experimental option to control chunk optimization (#…

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…7738)

graphite-app bot force-pushed the 01-03-add_new_option_to_opt_out_chunk_optimization branch from 0840413 to d2a77eb Compare January 3, 2026 16:29

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release: v1.0.0-beta.59 #7774

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release: v1.0.0-beta.59 #7786

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feat(option): add experimental option to control chunk optimization#7738

feat(option): add experimental option to control chunk optimization#7738
graphite-app[bot] merged 1 commit intomainfrom
01-03-add_new_option_to_opt_out_chunk_optimization

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