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Dunqing
4eb074e69d
Adds `MangleOptions::reserved` — equivalent to terser / uglify-js / swc `mangle.reserved`: names in the set are never used as mangled names, and bindings that already carry them keep them. Default empty; default output is byte-identical to main (minsize snapshot unchanged). ## Motivation Node's cjs-module-lexer detects a CommonJS module's named exports by **lexically** scanning for `exports.<name> =` / `module.exports` token patterns — no scope analysis ([its README documents renamed identifiers as "DETECTS: NO EXPORTS"](https://github.com/nodejs/cjs-module-lexer)). UMD / CommonJS wrappers bind `exports` / `module` as ordinary function parameters, and the mangler renames them, erasing every named export the lexer can see. Surfaced by the monitor-oxc mangler runtime test ([failing run](https://github.com/oxc-project/monitor-oxc/actions/runs/28569108563/job/84702922472), previously masked by #24033 / #24036): `archiver` does `import { queue } from "async"`, and `async`'s dist is a UMD bundle — mangled, the factory parameter `exports` became `e` and node fails with `Named export 'queue' not found`. With `reserved: ["exports", "module"]` the output imports correctly (verified end-to-end in node, including running a queue task). ## Why an opt-in list instead of always keeping these names Renaming them is ecosystem-standard. Verified empirically — minifying the same UMD sample and importing it in node: | minifier | renames `exports` param? | `import { queue }` from its output | escape hatch | | --- | --- | --- | --- | | terser 5.48 | yes | fails | `mangle.reserved` (verified working) | | uglify-js 3.19 | yes | fails | `reserved` (verified working) | | esbuild 0.28 `--minify` | yes | fails | none for identifier mangling | | swc | yes | fails | terser-style `mangle.reserved` ([swc#3424](https://github.com/swc-project/swc/issues/3424)) | An earlier revision of this PR kept `exports` / `module` unconditionally; the Minification Size check showed the real cost: ~1% minified on UMD-heavy files (d3: +3.3 kB from ~590 `exports` references, flipping it to *larger than esbuild*), because the point is keeping the literal 7-char token at every export site. No other minifier pays this by default — and rolldown bundles bind `exports` / `module` in every CJS interop wrapper, where node's lexer never looks. So oxc gets the same escape hatch as terser/swc, with the same name. `MangleOptions` loses `Copy` (it now holds the set); construction sites switch to `..MangleOptions::default()` / `clone()`. Exposed in `oxc-minify` NAPI options (`mangle.reserved: string[]`) and the mangler example (`--reserve-exports`). monitor-oxc will pass `["exports", "module"]` for its mangler runtime test (its corpus imports prebuilt CJS/UMD dists directly). For reference, esbuild solves this for its *own* node-platform CJS bundles differently — a dead-code annotation `0 && (module.exports = { a, b })` that cjs-module-lexer recognizes ([esbuild#960](https://github.com/evanw/esbuild/issues/960), [cjs-module-lexer#44](https://github.com/nodejs/cjs-module-lexer/issues/44)); verified that pattern also works appended to fully-mangled output. That could be a future zero-size-cost alternative at the minifier level.