fix: keep source map source names as emitted in maps and stack frames

[dannyhw]

Fixes #1468.

This fixes both bugs from the issue, using the corrected root cause from the follow-up comment. Checking further showed the scope is wider than the issue describes, in three ways:

• Bug 1 also affects Rspack. Rspack only drops sourceRoot for swc output. When Babel writes the map (@callstack/repack/babel-loader, or babel-swc-loader without swc), Rspack names files src/<dir>/<absolute path> too. Workspace packages in a monorepo get the same doubled name.
• Bug 2 is not only about ^. source-map passes every source name through new URL(). That encodes spaces and non-ASCII characters (Home Screen.tsx, Écran.tsx), so standalone apps are affected too, not just files outside the project root.
• The %5E comes from source-map, not parseUrl, as the follow-up showed. Decoding only in parseUrl brings back the code frame, but the response file stays encoded, so tapping a frame in LogBox still does nothing.

Changes

1. Loaders: removed sourceRoot: this.context from babelLoader and both transforms in babelSwcLoader. Upstream babel-loader doesn't set it either. It can still be set through babelOverrides / swcOverrides.
2. Symbolicator: prepareSourceMap (renamed from normalizeInvalidWebpackSourceUrls) escapes % in every source name before SourceMapConsumer reads the map. decodeURIComponent is then an exact inverse of the consumer's encoding, so lookup.source comes back exactly as the bundler emitted it. A file name that really contains % is not decoded twice. The embedded-content lookup re-escapes the name, so sourceContentFor still matches. That one change fixes the /symbolicate response, /open-stack-frame and the Symbolicated stack frame log line.
3. parseUrl: returns the decoded pathname, falling back to the raw path if the escape sequence is malformed. symbolicator.getSource passes it raw file names, and the asset route passes a param Fastify has already decoded. new URL() was encoding both again.

The 5.4 canary changes are all kept. #1434 (remote source URLs): __repack_source__ URLs still come out encoded, and getRemoteSource and getPrintableFile decode them as before (there's a test for this). #1446 (getSource with absolute paths) is untouched and now actually gets used for nosources-* maps.

Tests

• tests/integration/src/loaders/source-map-sources.test.ts (new). It compiles a small on-disk project with webpack and Rspack, through both babel-loader and babel-swc-loader, and checks that every file is named once by its absolute path in the source map. The project has app files, a space in a path, a local node_modules dependency, a hoisted node_modules dependency and a workspace package. On main, 3 of 4 cases fail; only Rspack + swc passes. With the fix, all 4 pass, in about 0.4s. @swc/core is linked into the fixture so webpack exercises the swc path too, and hermes-parser is added as a test dev dependency. The project is written to a temp directory, as NativeEntryPlugin.srcLayout.test.ts already does.
• Symbolicator.test.ts: covers [projectRoot^2], a space, non-ASCII, a literal %25 and an absolute path with a space. For each it checks the frame file, the code frame from embedded content, and the no-sources fallback, where getSource must receive the raw name. It also checks that remote __repack_source__ URLs stay encoded, and that the log line strips a [projectRoot^N] placeholder. On main, 11 of these fail.
• parseUrl.test.ts / resolveProjectPath.test.ts: decoded paths, malformed escapes, and parseUrl → resolveProjectPath composed the way the dev server does it.

Manual verification

apps/tester-app with devtool: 'nosources-source-map' on both bundlers. I symbolicated a frame from src/App.tsx and one from react-native/.../ActionSheetIOS.js with curl, then posted each result to /open-stack-frame with REACT_EDITOR pointing at a stub script that records its arguments:

	webpack	Rspack
[projectRoot]/ sources / doubled	32 / 0	32 / 0
src/App.tsx frame file	[projectRoot]/src/App.tsx	[projectRoot]/src/App.tsx
node_modules frame file	[projectRoot^2]/node_modules/...	[projectRoot^2]/node_modules/...
code frame (from disk)	both frames	both frames
path the editor received	exists, both frames	exists, both frames

Known limitation

A literal %XX sequence in a directory name is now decoded by parseUrl, so symbolicator.getSource or an asset request for it would look up the decoded name. Asset file names are already sanitised to [a-z0-9_], and the Symbolicator keeps literal % exact. In return, paths with spaces, non-ASCII characters or ^ now work, which is far more common.

[changeset-bot]

🦋 Changeset detected

Latest commit: 5c8f026

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 6 packages

Name	Type
@callstack/repack	Patch
@callstack/repack-dev-server	Patch
@callstack/repack-plugin-expo-modules	Patch
@callstack/repack-plugin-nativewind	Patch
@callstack/repack-plugin-reanimated	Patch
@callstack/repack-init	Patch

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Project	Deployment	Actions	Updated
repack-website	Ready	Preview	Sep 26, 2026 12:21pm UTC