Preserve Platform write targets during inlining - #1890
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A second pass found that the original ancestor walk classified every expression nested anywhere under an assignment LHS as a write. That incorrectly prevented inlining reads such as |
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@vzaidman has imported this pull request. If you are a Meta employee, you can view this in D118440964. |
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Summary: Publish Metro 0.87.1 from `main`. Changelog: [Internal] Pull Request resolved: #1926 Test Plan: ``` node scripts/updateVersion.js 0.87.1 sl diff --stat ``` Only the 17 `packages/*/package.json` manifests change, and every `0.87.0` reference is replaced. Draft release notes (from the 91 commits in v0.87.0...main - reverted and internal-only changes omitted): ``` - **[Feature]**: Add `resolver.schemeResolvers` to resolve URI-scheme-prefixed specifiers (eg `foo:bar`) with custom resolvers (#1804 by robhogan) - **[Feature]**: Resolve `metro:babel-runtime/<path>` imports to Metro's own `babel/runtime` dependency (8388f71 by robhogan) - **[Feature]**: `metro-file-map`: Add `crawlerFactory` to optionally replace the built-in Watchman / Node crawlers (68022f0 by vzaidman) - **[Feature]**: `metro-babel-transformer`: Pass `inlinePlatform` to Babel presets via `caller` (6bbe095 by robhogan) - **[Fix]**: Replace `image-size` dependency with vendored parsers, fix CVE alerts (#1860 by robhogan) - **[Fix]**: Include `charset=utf-8` in the `Content-Type` of text assets and source files served by the dev server (#1888 by robhogan) - **[Fix]**: Preserve `Platform.OS` write targets during constant inlining (#1890 by OskarEichler) - **[Fix]**: Inline the last duplicate key from static `Platform.select` object literals (#1889 by OskarEichler) - **[Fix]**: `FallbackWatcher` no longer misses files written to a directory while it is being crawled (#1907 by robhogan) - **[Fix]**: `HttpStore`: Handle socket errors during writes, so they're retried rather than crashing the process (fad3b88) - **[Fix]**: Treat `CI=false` and `CI=0` as not-CI when defaulting `watch`. CI is now detected from `process.env.CI` only, dropping the `ci-info` dependency (61e4592 by robhogan) - **[Fix]**: Fix Fast Refresh hitting undefined modules when using lazy (segmented) bundles in dev (c70d0ae by robhogan) - **[Performance]**: `FallbackWatcher`: Drop `walker` dependency, reduce crawl RSS by ~34% and peak heap by ~41% (#1906 by robhogan) - **[Performance]**: Don't emit redundant empty dependency map arrays for modules with no dependencies (#1858 by robhogan) - **[Types]**: Restore publishing of private (underscore-prefixed) fields in TypeScript declarations (#1876 by robhogan) - **[Types]**: Fix async functions being inferred as returning `void` (not `Promise<void>`), eg `MetroServer#end` (#1909 by robhogan) - **[Types]**: Tidy up generated types, allow nullable props to be omitted in more places (#1885 by robhogan) > NOTE: Experimental features are not covered by semver and can change at any time. - **[Experimental]**: Add `serializer.unstable_inlineDependencyMap` to inline module IDs at serialisation time (#1786 by robhogan) - **[Experimental]**: Add `serializer.unstable_getAsyncDependencyPath` to supply custom `paths` to framework-defined `__loadBundleAsync` (#1855 by robhogan) - **[Experimental]**: Remove `transformer.unstable_renameRequire` - `require` is never renamed (42577f7 by robhogan) - **[Experimental]**: `experimentalImportSupport`: Fix `export * from` re-exporting the source module's default export (#1777 by robhogan) **Full Changelog**: v0.87.0...v0.87.1 ``` Reviewed By: zeyap Differential Revision: D119675927 Pulled By: GijsWeterings fbshipit-source-id: daf17f3501b4725c21c39b4dfd5c82b95e01dca5
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Summary
Metro replaces
Platform.OSwith a string literal unless it is the direct left side of an assignment. Update/delete expressions, destructuring assignment targets, and direct or nestedfor...in/for...oftargets can therefore be changed semantically or make Babel abort with an invalid literal assignment target.Walk the member expression's ancestors and preserve it whenever the containing expression is the left side of an assignment or loop, or the argument of an update/delete operation. The React Native Babel preset has a parallel transform; companion React Native PR #58252 applies the same guard there.
Changelog:
Test plan
for...inandfor...oftargets.for...oftarget; the fixed suite preserves all eight forms.metro-transform-pluginssuites pass: 6/6 suites, 160/160 tests, 41 snapshots.git diff --checkpass.No public API or intended read-transform behavior changes.