[1.0.0-rc.2] - 2026-01-28

⚡ Lazy Barrel Optimization

• Skips compilation of unused re-export modules in side-effect-free barrel modules
• Particularly beneficial for projects importing from large component libraries

For large component libraries like Ant Design, when you import just one component:

import { Button } from 'antd';
Button;

By enabling lazy barrel, Rolldown reduces the number of compiled modules by 90% and speeds up the build by 2-4x.

Enable it in your config:

export default {
  experimental: {
    lazyBarrel: true,
  },
};

For more details, see the https://rolldown.rs/in-depth/lazy-barrel-optimization

💥 BREAKING CHANGES

• expose \0rolldown/runtime in transform hook (refactor!: expose \0rolldown/runtime in transform hook #8068) by @hyf0
• rename rolldown:runtime to \0rolldown/runtime.js (refactor!: rename rolldown:runtime to \0rolldown/runtime.js #8067) by @hyf0

🚀 Features

• remove inlined constants in smart mode (feat: remove inlined constants in smart mode #8085) by @sapphi-red
• allow more options for this.emitFile with type: 'prebuilt-chunk' (feat: allow more options for this.emitFile with type: 'prebuilt-chunk' #8062) by @sapphi-red
• warn when both code and postBanner contain shebang (feat: warn when both code and postBanner contain shebang #8039) by @copilot

🐛 Bug Fixes

• update the links to Rolldown docs in the error messages (fix: update the links to Rolldown docs in the error messages #8103) by @sapphi-red
• handle tsconfig.json load errors (fix: handle tsconfig.json load errors #8105) by @sapphi-red
• include inlined constants in namespace object (fix: include inlined constants in namespace object #8099) by @sapphi-red
• vite test ci (fix: vite test ci #8084) by @IWANABETHATGUY
• renamer: nested binding shadowing external module namespace in UMD/IIFE formats (fix(renamer): nested binding shadowing external module namespace in UMD/IIFE formats #8083) by @Dunqing
• deduplicate ESM chunk imports by canonical symbol (fix: deduplicate ESM chunk imports by canonical symbol #8059) by @IWANABETHATGUY
• refine side-effect detection for BigInt and RegExp (fix: refine side-effect detection for BigInt and RegExp #8060) by @IWANABETHATGUY
• rust: use string literal span for new URL error diagnostic (fix: use string literal span for new URL error diagnostic #8043) by @valadaptive
• rust: use ModuleType::Asset for new URL imports (fix(rust): use ModuleType::Asset for new URL imports #8035) by @valadaptive
• CJS-ESM interop - property assignment on CJS module exports (fix: CJS-ESM interop - property assignment on CJS module exports #8006) by @IWANABETHATGUY
• eliminate the facade chunk if the dynamic entry module has been merged into common chunk (fix: eliminate the facade chunk if the dynamic entry module has been merged into common chunk #8046) by @IWANABETHATGUY
• Inlining dynamic imports broken with multiple entry points (fix: Inlining dynamic imports broken with multiple entry points #8037) by @IWANABETHATGUY
• devtools: revert Chunk#id to Chunk#chunk_id (fix(devtools): revert Chunk#id to Chunk#chunk_id #8040) by @hyf0
• invert __exportAll parameter logic to reduce default output size (fix: invert __exportAll parameter logic to reduce default output size #8036) by @copilot
• </script tag search should be case insensitive (fix: </script tag search should be case insensitive #8033) by @IWANABETHATGUY
• use directory name as-is for the variable name even if the name contained . (fix: use directory name as-is for the variable name even if the name contained . #8029) by @copilot
• dev/lazy: remove unnecessary rewrite from top level this to undefined (fix(dev/lazy): remove unnecessary rewrite from top level this to undefined #8020) by @hyf0
• dev/lazy: should keep lazy entries imports for patch file (fix(dev/lazy): should keep lazy entries imports for patch file #8019) by @hyf0
• output.generatedCode.preset: 'es2015' was not set by default (fix: output.generatedCode.preset: 'es2015' was not set by default #8026) by @sapphi-red
• node: align option validator to types (fix(node): align option validator to types #8023) by @sapphi-red
• node: allow output.strictExecutionOrder by the option validator (fix(node): allow output.strictExecutionOrder by the option validator #8022) by @sapphi-red
• types: return this from on / off methods of RolldownWatcher (fix(types): return this from on / off methods of RolldownWatcher #8015) by @sapphi-red

🚜 Refactor

• rolldown_plugin_vite_dynamic_import_vars: remove v1 implementation (refactor(rolldown_plugin_vite_dynamic_import_vars): remove v1 implementation #8096) by @shulaoda
• rolldown_plugin_vite_import_glob: remove v1 implementation (refactor(rolldown_plugin_vite_import_glob): remove v1 implementation #8095) by @shulaoda
• lazy-barrel: restructure lazy barrel implementation (refactor(lazy-barrel): restructure lazy barrel implementation #8070) by @shulaoda
• remove use_built_ins and use_spread from internal JSX options (refactor: remove use_built_ins and use_spread from internal JSX options #8079) by @sapphi-red
• remove experimental.transformHiresSourcemap (refactor: remove experimental.transformHiresSourcemap #8055) by @copilot
• rust: use is_data_url more consistently (refactor(rust): use is_data_url more consistently #8042) by @valadaptive
• use FxIndexMap to store EntryPoint (refactor: use FxIndexMap to store EntryPoint #8032) by @IWANABETHATGUY
• node: add type checks that ensures validator schema is up to date with types (refactor(node): add type checks that ensures validator schema is up to date with types #8024) by @sapphi-red

📚 Documentation

• link to vite plugin registry (docs: link to vite plugin registry #8086) by @sapphi-red
• lazy-barrel: improve documentation and enable in sidebar (docs(lazy-barrel): improve documentation and enable in sidebar #8072) by @shulaoda
• add more examples and details (docs: add more examples and details #8054) by @sapphi-red
• in-depth: add dead code elimination page (docs(in-depth): add dead code elimination page #8007) by @sapphi-red
• update status from beta to release candidate (docs: update status from beta to release candidate #8012) by @shulaoda

⚡ Performance

• run inline-const pass for modules that are affected by inlining (perf: run inline-const pass for modules that are affected by inlining #8064) by @sapphi-red

🧪 Testing

• lazy-barrel: use package.json sideEffects instead of plugin hook (test(lazy-barrel): use package.json sideEffects instead of plugin hook #8077) by @shulaoda
• lazy-barrel: enable tests and add treeshake-behavior cases (test(lazy-barrel): enable tests and add treeshake-behavior cases #8071) by @shulaoda

⚙️ Miscellaneous Tasks

• deps: update crate-ci/typos action to v1.42.3 (chore(deps): update crate-ci/typos action to v1.42.3 #8087) by @renovate[bot]
• deps: update rollup submodule for tests to v4.56.0 (chore(deps): update rollup submodule for tests to v4.56.0 #8073) by @sapphi-red
• deps: update oxc to v0.111.0 (chore(deps): update oxc to v0.111.0 #8063) by @renovate[bot]
• deps: update dependency rolldown-plugin-dts to v0.21.6 (chore(deps): update dependency rolldown-plugin-dts to v0.21.6 #8076) by @renovate[bot]
• deps: update test262 submodule for tests (chore(deps): update test262 submodule for tests #8074) by @sapphi-red
• deps: update crate-ci/typos action to v1.42.2 (chore(deps): update crate-ci/typos action to v1.42.2 #8069) by @renovate[bot]
• deps: update oxc apps (chore(deps): update oxc apps #8066) by @renovate[bot]
• remove {@include ./foo.md} from d.ts files (chore: remove {@include ./foo.md} from d.ts files #8056) by @sapphi-red
• deps: update dependency oxlint-tsgolint to v0.11.2 (chore(deps): update dependency oxlint-tsgolint to v0.11.2 #8057) by @renovate[bot]
• deps: update github-actions (chore(deps): update github-actions #8050) by @renovate[bot]
• deps: update npm packages (chore(deps): update npm packages #8051) by @renovate[bot]
• deps: update rust crates (chore(deps): update rust crates #8049) by @renovate[bot]
• debug: add IdxExt debug trait for human-readable index debugging (chore(debug): add IdxExt debug trait for human-readable index debugging #8045) by @IWANABETHATGUY
• deps: update dependency rolldown-plugin-dts to v0.21.5 (chore(deps): update dependency rolldown-plugin-dts to v0.21.5 #8034) by @renovate[bot]
• deps: update oxc resolver to v11.16.4 (chore(deps): update oxc resolver to v11.16.4 #8031) by @renovate[bot]
• deps: update dependency rolldown-plugin-dts to v0.21.4 (chore(deps): update dependency rolldown-plugin-dts to v0.21.4 #8030) by @renovate[bot]
• deps: update dependency rust to v1.93.0 (chore(deps): update dependency rust to v1.93.0 #8018) by @renovate[bot]
• archive 2025 beta changelog (chore: archive 2025 beta changelog #8014) by @shulaoda
• update release workflow version pattern from beta to rc (ci: update release workflow version pattern from beta to rc #8013) by @shulaoda

❤️ New Contributors

• @valadaptive made their first contribution in #8043