docs: rolldown and oxc

This commit is contained in:
Julien Calixte
2026-03-22 01:23:13 +01:00
parent d1bb9fa182
commit 1aef212a36

View File

@@ -52,10 +52,16 @@ var dn=`$ark`,fn=2;for(;dn in globalThis;)dn=`$ark${fn++}`;var pn=dn;
Safari throws: `SyntaxError: Unexpected keyword 'in'. Expected a ';' following a return statement.` Safari throws: `SyntaxError: Unexpected keyword 'in'. Expected a ';' following a return statement.`
Chrome and Firefox appear to tolerate the malformed output. Chrome and Firefox appear to tolerate the malformed output.
## Reproduction attempts
Direct Rolldown calls (even with the full `arktype` + `@better-fetch/fetch` bundle) do **not** reproduce the bug. It only manifests through Vite's full production build pipeline. This strongly suggests the issue is in the interaction between **Vite's module preprocessing** (dependency pre-bundling, plugin transforms, scope-flattening of ESM modules) and Rolldown's minifier `sequences` optimization pass.
Hypothesis: Vite's pipeline produces a flattened scope where multiple `var` declarations from different original modules are consecutive. When the `sequences` optimizer then tries to fold those `var` declarations into the `for` loop init, it incorrectly drops the `for(var ` prefix when the loop condition contains the `in` operator.
## Notes ## Notes
- The bug does **not** reproduce with a minimal isolated input — it is triggered by Rolldown merging multiple module-level `var` declarations across bundled modules before applying the loop optimization.
- Related closed issue: [rolldown/rolldown#8146](https://github.com/rolldown/rolldown/issues/8146) — "Minifier incorrectly merges statements into for-in expression via comma operator" - Related closed issue: [rolldown/rolldown#8146](https://github.com/rolldown/rolldown/issues/8146) — "Minifier incorrectly merges statements into for-in expression via comma operator"
- To reproduce: run `pnpm build` in this project **without** `build.minify: "esbuild"` — the broken chunk is `getAuthor-*.js`
## Workaround ## Workaround