fix: resolve absolute stack frame paths in the webpack compiler

[giaBaoJS]

Summary

• guard the webpack compiler's getSource with path.isAbsolute, matching the Rspack compiler
• add getSource unit tests covering both the absolute and the relative case

Why

start.ts runs every symbolicator request through resolveProjectPath before handing it to the compiler:

repack/packages/repack/src/commands/start.ts

Lines 210 to 214 in b7a8611

	getSource: (url) => {
	let { resourcePath, platform } = parseUrl(url, platforms);
	resourcePath = resolveProjectPath(resourcePath, cliConfig.root);
	return compiler.getSource(resourcePath, platform);
	},

resolveProjectPath ends in path.resolve, so the compiler receives an absolute path. rspack/Compiler.ts:353 handles that:

const filePath = path.isAbsolute(filename)
  ? filename
  : path.join(this.rootDir, filename);

webpack/Compiler.ts:279 did not:

const filePath = path.join(this.rootDir, filename);

so the root was prepended a second time. With rootDir /project, a frame at /outside/project/file.js was read from /project/outside/project/file.js, which does not exist. getSource threw, and the redbox rendered the frame with no code frame.

This is not limited to files outside the project root. SourceMapPlugin emits [projectRoot]/... for every in-project module, resolveProjectPath turns that into an absolute path, and path.join('/project', '/project/src/App.tsx') is /project/project/src/App.tsx. So on webpack every symbolicated frame lost its source, while Rspack was fine.

It looks like an oversight rather than a deliberate difference. git log -S "path.isAbsolute(filename)" returns exactly one commit:

b15b7d77 fix: sourcemaps handling in dev & prod (#1172)

That commit is the one that introduced resolveProjectPath and wired it into both start commands, including packages/repack/src/commands/webpack/start.ts. It added the path.isAbsolute guard only to rspack/Compiler.ts. The webpack producer was updated, the webpack consumer was not.

This is the getSource bullet from the v6 list in #1421. It is an independent v5 bug that stands on its own, so I am not marking #1421 as closed. Happy to have it folded into the unification work instead if you would rather handle it there.

Validation

• pnpm --filter @callstack/repack test: 33 suites, 301 tests passed (299 before)
• pnpm test: 10 tasks successful
• pnpm typecheck: 11 tasks successful. biome check: 481 files, clean
• counterfactual: reverting only Compiler.ts while keeping the tests turns reads an absolute filename as-is red on the assertion, Rejected to value: [CLIError: File /outside/project/file.js not found], not on an import or compile error. Instrumenting the spy shows readFile receiving /project/outside/project/file.js
• non-vacuity in the other direction: replacing the change with const filePath = filename (dropping the join entirely) turns resolves a relative filename against the project root red, so neither test passes both ways

[changeset-bot]

🦋 Changeset detected

Latest commit: 6ae4f65

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

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