feat: restructure react refresh support for rspack 2 by dannyhw · Pull Request #1402 · callstack/repack

dannyhw · 2026-07-06T18:35:11Z

Part of the Rspack 2 support stack (reference implementation: #1393, design doc: agent_context/rspackv2-jul2026/design.md).

Restructures React Refresh so DevelopmentPlugin works under both Rspack majors and webpack. This is the only PR in the stack that touches packages/repack/package.json's dependency surface.

Design: split on the rspack major

@rspack/plugin-react-refresh@1 cannot stay: its module-load-time deprecated_runtimePaths access hard-crashes when v2 of the plugin is installed, and depending on v1 while needing ^2 as a peer is unresolvable (same package name). Per the design doc's React Refresh decision (maintainer-validated in the #1393 review — vendoring the client files is fine, deprecated_runtimePaths was only ever a convenience):

Rspack >= 2: apply the official @rspack/plugin-react-refresh v2 with its integrator options — injectEntry: false (Re.Pack controls entry placement per entrypoint), forceEnable: true (DevelopmentPlugin already gates on devServer.hot), and reactRefreshLoader pointed at Re.Pack's React Native-aware react-refresh-loader. The package is ESM-only (named export only), so it is require()d lazily inside the rspack-2 branch — it is never evaluated for webpack/Rspack 1 users — and resolved from the project context with an actionable error when missing.
webpack + Rspack 1: keep the existing manual wiring, now pointed at client runtime files vendored from @rspack/plugin-react-refresh@2.0.2 (MIT) instead of the removed v1 dependency.

The behavioral fork is a single ternary on getRspackMajorVersionFromCompiler(compiler); everything else is extraction. A per-bundler plugin split (floated in the #1393 review) is not warranted for one ~10-line fork.

Vendor directory placement (review feedback)

The vendored files live at package-root packages/repack/vendor/react-refresh/ — outside src/, per the review ask. They are plain JS client-runtime modules bundled by the user's compiler, so they ship as-is via package.json#files (no babel processing) and are excluded from biome. LICENSE in the directory carries the upstream MIT license plus a provenance note: the files are verbatim upstream v2.0.2 apart from provenance headers and repo formatting (no functional edits; re-derivation instructions for future bumps included).

Footprint check (review feedback: minimize the DevelopmentPlugin diff)

Verified with git diff --color-moved=dimmed-zebra --color-moved-ws=allow-indentation-change origin/main...HEAD -- packages/repack/src/plugins/DevelopmentPlugin.ts: the manual wiring (setupManualReactRefresh) registers as a move of the old inline block (193 moved lines). The only non-moved lines inside it are the three intentional deltas:

Runtime-file source: ReactRefreshPlugin.deprecated_runtimePaths destructure → require.resolve('../../vendor/react-refresh/*.js') (resolves identically from src/plugins and dist/plugins).
Define-flag swap: __react_refresh_error_overlay__: false + __react_refresh_socket__: false → __reload_on_runtime_errors__: false — the v2.0.2 client files dropped the overlay/socket knobs and read the new flag instead. Value semantics unchanged: all web-oriented behaviors stay off; RN surfaces errors via LogBox.
Loader rule matcher: include: → test: with the same regex (both match the resource path here; test is the semantically correct key).

Two non-substantive accompaniments, listed for completeness rather than hidden: the loader-rule regexes are hoisted into module constants (REACT_REFRESH_LOADER_TEST / REACT_REFRESH_LOADER_EXCLUDE, identical literal values) because both branches now share them, and comments were updated around the moved block. Everything else in the file diff is genuinely new code for the rspack-2 branch (resolveReactRefreshPluginRequest, setupOfficialReactRefresh).

Dependency changes

Package	Before	After	Notes
`@rspack/plugin-react-refresh`	dependency `1.0.0`	optional peerDependency `^2.0.0`	Rspack 2 users install it in their project; webpack/Rspack 1 users need nothing
`@rspack/plugin-react-refresh` (devDep)	—	`^2.0.2`	so the workspace/tests exercise the official-plugin path
`package.json#files`	—	+ `"vendor"`	ships the vendored client runtime

What users must do:

Rspack 2: install @rspack/plugin-react-refresh@^2 and react-refresh (pnpm-strict layouts don't hoist Re.Pack's react-refresh copy into the official plugin's resolution scope).
Rspack 1 / webpack: nothing. Runtime behavior is preserved via the vendored upstream v2.0.2 client files (MIT, LICENSE + provenance included) — same wiring shape (ProvidePlugin ×2 + DefinePlugin + loader rule + entry), same values modulo the enumerated define-flag rename that the v2.0.2 client files require.

Stack position

Parallel set, based on #1398 (types + dual-major test infra) ← #1397 (Node guard) ← #1394 (version helpers). No shared files with the other parallel-set PRs (#1399, #1400, #1401) apart from uniquely-named changesets; this is the only one touching packages/repack/package.json and the lockfile.

Validation

pnpm turbo run typecheck test --force: 17/17 tasks green (includes tester-app bundle/start tests, which exercise the dev server under both the rspack and webpack lanes).
packages/repack: pnpm test (v2 lane) and pnpm test:rspack1 (v1 lane) — 282/282 each.
pnpm lint:ci: clean (vendored files excluded as intended).
Webpack-path evidence (review feedback: test both bundler paths): started tester-app with USE_WEBPACK=1 and fetched the served dev bundle — it contains all three vendored runtime modules (vendor/react-refresh/reactRefresh.js ×90 refs, reactRefreshEntry.js ×3, refreshUtils.js ×3) and zero references to @rspack/plugin-react-refresh.
Vendored files diffed against the actual @rspack/plugin-react-refresh@2.0.2 client/ files from the registry: identical apart from provenance headers and formatting (no functional deltas).
On the reference branch, this exact code was device-validated (Pixel 7 + iPhone 17 simulator): live React Refresh edit+revert under Rspack 2 (official plugin) and Rspack 1 (vendored runtime).

Pending manual verification: a device HMR pass on this branch under Rspack 1, Rspack 2, and webpack. The reference branch (#1393) passed the Rspack 1 + Rspack 2 device HMR checks with identical code, but this branch has not yet had its own on-device pass — flagging so it can happen before/at merge.

DevelopmentPlugin now splits on the detected rspack major: - rspack >= 2 applies the official @rspack/plugin-react-refresh (v2) with injectEntry: false (Re.Pack controls entry placement per entrypoint), forceEnable: true, and Re.Pack's own react-refresh-loader. The package is ESM-only, so it is loaded lazily inside the rspack-2 branch and resolved from the project context with an actionable error when missing. - webpack and rspack 1 keep the existing manual wiring, now pointed at client runtime files vendored from @rspack/plugin-react-refresh@2.0.2 (MIT) into the package-root vendor/react-refresh/ directory, shipped as-is via package.json#files and excluded from biome. The @rspack/plugin-react-refresh@1.0.0 dependency is removed (its module-load-time deprecated_runtimePaths access crashes under the v2 plugin); the v2 plugin becomes an optional peer dependency instead, so rspack 2 users install it (plus react-refresh) in their project.

vercel · 2026-07-06T18:35:23Z

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Project	Deployment	Actions	Updated (UTC)
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changeset-bot · 2026-07-06T18:35:24Z

🦋 Changeset detected

Latest commit: 05b9027

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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Click here if you're a maintainer who wants to add another changeset to this PR

…oader rule The manual React Refresh rule only excluded node_modules, so in workspace (symlinked) installs the vendored runtime files under packages/repack/vendor/react-refresh matched the rule and were processed by the react-refresh loader themselves. Mirror the upstream plugin's self-exclusion by also excluding the three vendored file paths. The official plugin path (Rspack 2) already appends these exclusions internally.

dannyhw

codex review: Posting the actionable findings from the latest re-review.

dannyhw · 2026-07-07T13:33:19Z

+    // where require() of an ESM module is supported
+    const { ReactRefreshRspackPlugin } = require(pluginPath);
+
+    new ReactRefreshRspackPlugin({


codex review: Superseded by the corrected reply below; the first version lost inline identifiers during shell quoting.

codex review: Correction to the previous comment: the stripped identifiers were ReactRefreshRspackPlugin and @rspack/plugin-react-refresh. The requested coverage should prove that the Rspack 2 branch applies ReactRefreshRspackPlugin with Re.Pack's loader and injected entry path; webpack/Rspack 1 use the vendored runtime without evaluating @rspack/plugin-react-refresh; and Rspack 2 reports the intended actionable error when that optional peer is absent.

dannyhw · 2026-07-07T13:33:19Z

  "peerDependencies": {
    "@module-federation/enhanced": ">=0.6.10",
    "@rspack/core": ">=1",
+    "@rspack/plugin-react-refresh": "^2.0.0",


codex review: Superseded by the corrected reply below; the first version lost the package name during shell quoting.

codex review: Correction to the previous comment: the stripped package name was @rspack/plugin-react-refresh. This PR makes @rspack/plugin-react-refresh an optional peer, but the current latest docs still say the plugin is shipped with Re.Pack and configured automatically. Please update the user-facing docs/install guidance in this PR or in the same stack so the package contract and docs agree.

This was referenced Jul 6, 2026

chore: per-major tester apps for the rspack 2 dual-support window #1403

Open

test: add dual-major rspack compatibility smoke suite #1404

Open

feat: support Rspack 2 alongside Rspack 1 - reference implementation (to be broken down) #1393

Closed

dannyhw commented Jul 6, 2026

View reviewed changes

Comment thread packages/repack/src/plugins/DevelopmentPlugin.ts

vercel Bot deployed to Preview July 6, 2026 19:23 View deployment

This was referenced Jul 6, 2026

feat: check module federation runtime-tools availability under rspack 2 #1400

Closed

docs: sync the rspack 2 design doc with review-round changes #1405

Merged

dannyhw commented Jul 7, 2026

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feat: restructure react refresh support for rspack 2#1402

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dannyhw commented Jul 6, 2026

Design: split on the rspack major

Vendor directory placement (review feedback)

Footprint check (review feedback: minimize the DevelopmentPlugin diff)

Dependency changes

Stack position

Validation

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