perf: disable preserve_parens across all parse paths#10057
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### What
Sets `preserve_parens: false` on every parser rolldown controls, so the oxc parser no longer emits a `ParenthesizedExpression` wrapper node for each `(expr)` in source:
- `EcmaCompiler::parse` — the primary JS/TS module parse
- `EcmaCompiler::parse_expr_as_program` — text / base64 / data-url modules
- `EcmaCompiler::dce_or_minify` — DCE / minify input (DCE already strips these, so this is a micro-opt that avoids allocating nodes that get removed anyway)
- `enhanced_transform` — the oxc transform path
- the vite `transform`, `import-glob`, and `dynamic-import-vars` plugins
Test-only and benchmark parsers (`cjs_export_analyzer` tests, sourcemap tests, side-effect-detector tests) are intentionally left untouched.
### Why
The wrapper nodes carry nothing codegen needs. In oxc, `GenExpr for ParenthesizedExpression` just delegates to the inner expression and re-derives parentheses from operator precedence:
```rust
impl GenExpr for ParenthesizedExpression<'_> {
fn gen_expr(&self, p: &mut Codegen, precedence: Precedence, ctx: Context) {
self.expression.print_expr(p, precedence, ctx);
}
}
```
So emitted code is identical whether or not the wrappers exist — the flag only affects the in-memory AST shape. Dropping them means fewer AST nodes to allocate and traverse in every scanner / finalizer / visitor pass, and removes an AST-shape inconsistency (DCE already stripped these nodes when tree-shaking ran, so the parsed AST previously differed depending on whether tree-shaking was enabled).
### Note
The existing paren-peeling helpers (`ast_scanner`, `generate_lazy_export`, the vite build-import-analysis plugin, `side_effect_detector::get_inner_expression`) are kept: paren nodes can still enter the AST via plugin `transform_ast` hooks that parse with their own options, and via internal synthesis in `rolldown_ecmascript_utils/src/ast_factory.rs`. `get_inner_expression` also peels TS `as` / `satisfies` / `!` wrappers, so it is needed regardless.
### Test
- Rust integration suite (`cargo test -p rolldown --test integration`, 1778 fixtures) with snapshots on: all pass with **zero** snapshot changes — output is byte-for-byte identical.
- Node fixtures for the three vite plugins (`import-glob`, `dynamic-import-vars`, `transform` / `ecma-transform`) and the transform paths all pass.
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## [1.1.4] - 2026-07-01 ### 🚀 Features - disable `experimental.lazyBarrel` by default (#10071) by @shulaoda ### 🐛 Bug Fixes - dev: disable lazy barrel in dev mode (#10060) by @shulaoda - generate: keep full JSON interface under preserveModules namespa… (#10056) by @IWANABETHATGUY - check finalize_other_specifiers in its own Debug attribute (#10032) by @shulaoda - serialize the KeepAssign unused minify option as "keep_assign" (#10031) by @shulaoda - keep fragments after the newline fragment in MagicString::last_line (#10023) by @shulaoda - generate: undeclared JSON named exports under preserveModules (#10020) (#10027) by @IWANABETHATGUY - deconflict: rename CJS-wrapped locals that shadow chunk-root bindings (#9921) by @IWANABETHATGUY - rolldown: keep entry facade when a shared chunk holds another entry's module (#9997) by @hyf0 - treeshake: also bail JSON default split when the object escapes (#9996) by @IWANABETHATGUY - don't classify await in a strict-mode function as top-level await (#9987) by @shulaoda - avoid spurious leading newline in addon hooks (banner/footer/intro/outro) (#9989) by @shulaoda - handle JSON default mutation bailouts (#9972) by @TheAlexLichter - plugin: make lazy hook metadata enumerable (#9991) by @TheAlexLichter - dev: make init errors in lazy-compiled modules catchable (#9981) by @h-a-n-a - treeshake: keep computed-key side effects on namespace member access (#9986) by @shulaoda - binding: validate replace plugin delimiters length instead of panicking (#9984) by @shulaoda - reconstruct nested rest patterns in into_expression (#9980) by @IWANABETHATGUY - reconstruct rest patterns as spread in into_expression (#9976) by @shulaoda - preserve export keyword on multi-declarator exports under keepNames (#9974) by @shulaoda - deterministically keep the shortest name for deduplicated assets (#9948) by @x1024 - treeshake: apply @__NO_SIDE_EFFECTS__ to cross-chunk namespace calls (#9960) by @IWANABETHATGUY ### 🚜 Refactor - drop redundant program scope enter/leave in finalizer (#10049) by @shulaoda - deconflict: extract collect_chunk_scope_captured_names (#10006) by @IWANABETHATGUY - unify pre-scan multi-declarator split into one decision site (#9982) by @IWANABETHATGUY - common: return bool from SymbolRef::is_not_reassigned (#9962) by @IWANABETHATGUY ### 📚 Documentation - rolldown: remove outdated comment for removing parenthesized expression (#10062) by @Dunqing - use GitHub-flavored alert for Etiquette note in contribution guide (#10012) by @IWANABETHATGUY - replace: explain the delimiters left and right boundaries (#9985) by @shulaoda - ast-mutation: remove stale Address Use section after pre-scan refactor (#9983) by @IWANABETHATGUY - remove fathom (#9968) by @mdong1909 - contribution-guide: code-format main branch references (#9966) by @IWANABETHATGUY - contribution-guide: fix stale REPL note and tidy wording (#9957) by @hyf0 - contribution-guide: clarify when to discuss before opening a PR (#9955) by @hyf0 ### ⚡ Performance - disable preserve_parens across all parse paths (#10057) by @Dunqing - common: inline declared_symbols with SmallVec (#9920) by @IWANABETHATGUY - common: pack TaggedSymbolRef into 8 bytes (#9919) by @IWANABETHATGUY - sourcemap: skip newline scan on the no-sourcemap join fast path (#9936) by @Boshen ### 🧪 Testing - dev: error in lazy module should be catchable (#9975) by @sapphi-red - dev: reject unknown lazy compile modules (#9969) by @sapphi-red ### ⚙️ Miscellaneous Tasks - deps: update actions/cache action to v6 (#10001) by @renovate[bot] - trigger vite ecosystem-ci from PR comments (#10058) by @shulaoda - deps: update napi to v3.10.0 (#10063) by @renovate[bot] - remove unused From impl for RolldownLabelSpan (#10055) by @shulaoda - remove dead Diagnostic::with_kind method (#10054) by @shulaoda - remove unused StatementExt methods (#10053) by @shulaoda - remove unused ExpressionExt methods (#10052) by @shulaoda - remove commented-out re_export_all_names field (#10051) by @shulaoda - deps: update pnpm to v11.9.0 (#10047) by @renovate[bot] - remove the unused BindingGenerateHmrPatchReturn napi type (#10034) by @shulaoda - remove the dead inline_entry_chunk_wrapping scaffolding (#10037) by @shulaoda - deps: bump oxc_resolver to 11.22.0 (#10045) by @Boshen - remove never-constructed MatchImportKind::_Ignore variant (#10041) by @shulaoda - remove the unused ScheduledBuild napi struct (#10033) by @shulaoda - remove dead compute_hmr_update_single method (#10040) by @shulaoda - drop the redundant visited.insert in manual code splitting (#10038) by @shulaoda - remove the dead output_assets vector in render_chunk_to_assets (#10036) by @shulaoda - remove the unused From<String>/Display impls for BindingLogLevel (#10035) by @shulaoda - deps: upgrade oxc to 0.138.0 and migrate to per-type AST construction (#10018) by @shulaoda - deps: update rust crates (#9911) by @renovate[bot] - deps: update test262 submodule for tests (#10016) by @rolldown-guard[bot] - deps: update github actions (#9999) by @renovate[bot] - deps: update npm packages (#10000) by @renovate[bot] ###◀️ Revert - "fix(plugin): make lazy hook metadata enumerable (#9991)" (#10005) by @shulaoda ### ❤️ New Contributors * @x1024 made their first contribution in [#9948](#9948) Co-authored-by: shulaoda <165626830+shulaoda@users.noreply.github.com>
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What
Sets
preserve_parens: falseon every parser rolldown controls, so the oxc parser no longer emits aParenthesizedExpressionwrapper node for each(expr)in source:EcmaCompiler::parse— the primary JS/TS module parseEcmaCompiler::parse_expr_as_program— text / base64 / data-url modulesEcmaCompiler::dce_or_minify— DCE / minify input (DCE already strips these, so this is a micro-opt that avoids allocating nodes that get removed anyway)enhanced_transform— the oxc transform pathtransform,import-glob, anddynamic-import-varspluginsTest-only and benchmark parsers (
cjs_export_analyzertests, sourcemap tests, side-effect-detector tests) are intentionally left untouched.Why
The wrapper nodes carry nothing codegen needs. In oxc,
GenExpr for ParenthesizedExpressionjust delegates to the inner expression and re-derives parentheses from operator precedence:So emitted code is identical whether or not the wrappers exist — the flag only affects the in-memory AST shape. Dropping them means fewer AST nodes to allocate and traverse in every scanner / finalizer / visitor pass, and removes an AST-shape inconsistency (DCE already stripped these nodes when tree-shaking ran, so the parsed AST previously differed depending on whether tree-shaking was enabled).
Note
The existing paren-peeling helpers (
ast_scanner,generate_lazy_export, the vite build-import-analysis plugin,side_effect_detector::get_inner_expression) are kept: paren nodes can still enter the AST via plugintransform_asthooks that parse with their own options, and via internal synthesis inrolldown_ecmascript_utils/src/ast_factory.rs.get_inner_expressionalso peels TSas/satisfies/!wrappers, so it is needed regardless.Test
cargo test -p rolldown --test integration, 1778 fixtures) with snapshots on: all pass with zero snapshot changes — output is byte-for-byte identical.import-glob,dynamic-import-vars,transform/ecma-transform) and the transform paths all pass.