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feat(transform): run React Compiler as a pre-transform pass#9671

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feat/react-compiler-transform
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feat(transform): run React Compiler as a pre-transform pass#9671
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feat/react-compiler-transform

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@Boshen

@Boshen Boshen commented Jun 8, 2026 •
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Run the React Compiler as a standalone pre-transform pass, before any other transform (define, TS/JSX lowering, DCE) runs, on the pristine AST.

Enabled via transform: { reactCompiler: true | ReactCompilerOptions }.

Where it runs

The compiler runs in the same position (first, before JSX lowering) across all three entry points, so bundled and unbundled (Vite dev) builds behave identically:

  • rolldown bundler — crates/rolldown/src/utils/pre_process_ecma_ast.rs (Step 1.5), rebuilding scoping for the downstream transformer.
  • Vite unbundled dev — crates/rolldown_plugin_vite_transform/src/lib.rs, between semantic build and the Transformer.
  • rolldown_common — react_compiler is threaded through BundlerTransformOptions so it is exposed to the Vite transform plugin.

Notes

  • The React Compiler is not part of the per-file oxc::transformer::TransformOptions; it is a separate pass, so it is threaded through separately and pulled out before the per-file options are consumed.
  • The standalone transform() API (EnhancedTransformOptions) does not expose React Compiler yet.
  • In the Vite plugin, jsx only accepts preserve as a string preset (Vite passes a resolved jsx options object); the bundler additionally accepts the react-jsx string shorthand.

Tests

  • transform/react-compiler — bundler path
  • builtin-plugin/ecma-transform/react-compiler — Vite transform plugin path

🤖 Generated with Claude Code

@Boshen Boshen mentioned this pull request Jun 8, 2026
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Boshen commented Jun 8, 2026

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@graphite-app graphite-app Bot changed the base branch from chore/upgrade-oxc-0.135.0 to graphite-base/9671 June 8, 2026 16:07
@graphite-app graphite-app Bot force-pushed the feat/react-compiler-transform branch from 7eed539 to 8371021 Compare June 8, 2026 16:14
@graphite-app graphite-app Bot force-pushed the graphite-base/9671 branch from 04849da to 5cfff49 Compare June 8, 2026 16:14
@graphite-app graphite-app Bot changed the base branch from graphite-base/9671 to main June 8, 2026 16:15
@graphite-app graphite-app Bot force-pushed the feat/react-compiler-transform branch from 8371021 to fdc4298 Compare June 8, 2026 16:15
@netlify

netlify Bot commented Jun 8, 2026 •
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✅ Deploy Preview for rolldown-rs canceled.

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🔨 Latest commit 1137df7
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@Boshen Boshen force-pushed the feat/react-compiler-transform branch 3 times, most recently from c3a5bf0 to eb4729c Compare June 9, 2026 14:12
@Boshen Boshen force-pushed the feat/react-compiler-transform branch from eb4729c to 1137df7 Compare June 9, 2026 15:02
@shulaoda

shulaoda commented Jun 10, 2026 •
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rolldown/crates/rolldown_binding/src/transform.rs

Lines 42 to 48 in 1137df7

fn enhanced_transform_internal(
filename: &str,
source_text: &str,
options: Option<BindingEnhancedTransformOptions>,
cache: Option<&TsconfigCache>,
yarn_pnp: bool,
) -> napi::Result<BindingEnhancedTransformResult> {

rolldown/crates/rolldown_common/src/utils/enhanced_transform.rs

Lines 261 to 266 in 1137df7

pub fn enhanced_transform(
filename: &str,
source_text: &str,
transform_options: EnhancedTransformOptions,
yarn_pnp: bool,
) -> EnhancedTransformResult {

rolldown/crates/rolldown_common/src/utils/enhanced_transform.rs

Lines 393 to 400 in 1137df7

let transform_ret = Transformer::new(&allocator, Path::new(filename), &oxc_transform_options)
.build_with_scoping(scoping, &mut program);
if !transform_ret.errors.is_empty() {
append_oxc_diagnostics(transform_ret.errors, &source, filename, &mut warnings, &mut errors);
if !errors.is_empty() {
return EnhancedTransformResult::new_for_error(errors, warnings, tsconfig_file_paths);
}
}

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@Boshen @shulaoda