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chore: support Yarn's pnpm nodeLinker#3010

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Saadnajmi merged 10 commits into
microsoft:mainfrom
Saadnajmi:saadnajmi/yarn-pnpm-mode
Jul 8, 2026
Merged

chore: support Yarn's pnpm nodeLinker#3010
Saadnajmi merged 10 commits into
microsoft:mainfrom
Saadnajmi:saadnajmi/yarn-pnpm-mode

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@Saadnajmi Saadnajmi commented Jul 7, 2026 •
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Summary

Switch Yarn's nodeLinker from node-modules to pnpm and make the monorepo build, lint, type-check, and bundle under the pnpm linker's strict (non-hoisted) node_modules layout. That layout surfaces phantom dependencies that previously resolved only via hoisting; this PR declares them, keeping upstream-tracked manifests as pristine as possible.

RNTester bundles for macOS (dev + production), and the fork's PR workflow is green: yarn install --immutable, constraints, test-ci (Jest), flow-check, lint, format-check, and Build RNTester.

Changed files (audited for minimal divergence)

File Why [macOS] tag
.yarnrc.yml nodeLinker: pnpm + a packageExtensions block declaring the per-package phantom deps in one fork-only place (so upstream manifests stay pristine) yes
.flowconfig module.name_mappers so @react-native/fantom / @react-native/core-cli-utils self-references resolve under pnpm yes
packages/rn-tester/metro.config.js one-line extraNodeModules alias for the react-native → react-native-macos redirect (not self-resolvable under pnpm) yes
docsite/.yarnrc.yml pin the standalone docsite to node-modules so the root pnpm setting doesn't break its Docusaurus build n/a (config)
.prettierrc list prettier-plugin-hermes-parser explicitly; Prettier 2.x auto-loaded it from a hoisted node_modules, which pnpm doesn't provide n/a (JSON)
package.json declare root dev-tooling deps (eslint config/plugins, @babel/* for scripts/build-types, metro/metro-config, yargs, etc.) that root configs/scripts use directly n/a (JSON)
yarn.lock mechanical n/a (generated)

Design notes

  • packageExtensions for per-package shims. The per-package phantom deps (metro, metro-config, metro-babel-transformer, invariant, hermes-estree, jest-docblock, jest-message-util, source-map, @babel/parser, @babel/plugin-syntax-flow) are declared centrally in .yarnrc.yml rather than editing seven individual manifests — verified that packageExtensions applies to workspace packages in Yarn 4.12.
  • Only third-party deps go in packageExtensions. The fork's yarn.config.cjs constraints inspect manifest deps and don't see packageExtensions entries; on release branches they pin @react-native/* deps to the release version. So no @react-native/* deps belong in packageExtensions — they'd escape that governance. (Verified via an A/B test on a simulated 0.83-stable tree.)
  • Scoped to what the fork actually runs. Changes that only served the upstream Test All workflow (the yarn-install composite action, code-analysis-bot, the ReactNativeApi.d.ts API snapshot) were intentionally left untouched — the fork's PR workflow doesn't use them.

Upstreamable subset

A few are genuine undeclared direct dependencies upstream too (masked there by Yarn 1 hoisting) and could be separate PRs to facebook/react-native — most cleanly @react-native/metro-babel-transformer declaring metro-babel-transformer. @react-native/codegen's @babel/parser is already declared upstream.

Test plan

yarn install
cd packages/rn-tester
node ../react-native/cli.js bundle --platform macos --dev true \
  --entry-file js/RNTesterApp.macos.js --bundle-output /tmp/RNTesterApp.macos.jsbundle
# plus: yarn constraints && yarn flow-check && yarn lint && yarn format-check && yarn test-ci

🤖 Generated with Copilot CLI

@Saadnajmi Saadnajmi requested a review from a team as a code owner July 7, 2026 07:52
@Saadnajmi Saadnajmi force-pushed the saadnajmi/yarn-pnpm-mode branch 3 times, most recently from 3ef3eb8 to eef9a9a Compare July 7, 2026 09:03
@Saadnajmi Saadnajmi force-pushed the saadnajmi/yarn-pnpm-mode branch 4 times, most recently from e17d24f to 88a7cd3 Compare July 7, 2026 10:18
Saadnajmi and others added 5 commits July 7, 2026 10:23
@Saadnajmi
chore: switch Yarn nodeLinker to pnpm
7506f83 
Switch the monorepo to Yarn's pnpm linker (strict, non-hoisted node_modules).
Pin the standalone docsite to nodeLinker: node-modules so this setting does not
leak into its Docusaurus build, which relies on hoisted resolution.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi
fix(metro): resolve deps and self-reference so RNTester bundles under…
595f10d 
… pnpm

Under the pnpm linker's strict layout, previously-hoisted dependencies must be
declared explicitly:

- rn-tester metro config imports mergeConfig from @react-native/metro-config
  instead of requiring metro-config directly, and maps the react-native-macos
  self-reference to the workspace via extraNodeModules (the react-native ->
  react-native-macos redirect is not self-resolvable under pnpm).
- Declare @react-native/babel-preset and @babel/runtime at the monorepo root.
- Declare @babel/parser in @react-native/codegen, which its built lib requires.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi
fix(lint,flow): declare eslint/flow/prettier phantom deps for pnpm
35306aa 
The pnpm linker's strict layout requires declaring dependencies that the JS
toolchain previously resolved through a hoisted node_modules.

ESLint:
- Declare @react-native/eslint-config and the plugins @react-native/eslint-plugin,
  @react-native/eslint-plugin-monorepo, @react-native/eslint-plugin-specs, plus
  @typescript-eslint/eslint-plugin, eslint-plugin-react-hooks and the
  jsonc-eslint-parser referenced by the root .eslintrc.
- Declare hermes-estree in @react-native/eslint-plugin-monorepo, which its
  rules require.

Prettier:
- List prettier-plugin-hermes-parser explicitly in .prettierrc plugins; Prettier
  2.x auto-loaded it from a hoisted node_modules, which pnpm does not provide.

Flow:
- Declare @babel/parser, @babel/traverse, @babel/types, hermes-estree, yargs,
  metro and metro-config at the root (used by scripts/build-types and helloworld).
- Declare the direct dependencies each package imports: @babel/plugin-syntax-flow
  (babel-plugin-codegen), metro (core-cli-utils), metro-babel-transformer
  (metro-babel-transformer), invariant (compatibility-check), and metro/
  metro-config/jest-docblock/jest-message-util/source-map (fantom).
- Add Flow module.name_mapper entries so @react-native/fantom and
  @react-native/core-cli-utils (including self-references) resolve under pnpm.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi
fix(build-types): normalize resolved import paths and refresh API sna…
aa0bcc9 
…pshot

Under the pnpm linker, API Extractor emitted module specifiers via their on-disk
(symlinked) path, e.g. .../node_modules/@react-native-macos/virtualized-lists.
Normalize these back to a bare package name in the generated snapshot so it is
deterministic regardless of linker, and regenerate the (previously stale)
ReactNativeApi.d.ts.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi
ci: make yarn-install and code-analysis-bot pnpm-compatible
1487d1d 
- yarn-install action uses 'yarn install --immutable' instead of the deprecated
  '--non-interactive --frozen-lockfile'. The --non-interactive flag silently
  exits 1 under the pnpm linker; --immutable is Yarn's recommended replacement
  and works with both linkers.
- code-analysis-bot filters blank lines so stray output under the pnpm linker
  does not shift its converter/JSON stream pairing and break parsing.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi Saadnajmi force-pushed the saadnajmi/yarn-pnpm-mode branch from 88a7cd3 to 1487d1d Compare July 7, 2026 17:25
Saadnajmi
Saadnajmi commented Jul 7, 2026
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Comment thread .github/actions/yarn-install/action.yml Outdated
Saadnajmi
Saadnajmi commented Jul 7, 2026
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Saadnajmi and others added 3 commits July 7, 2026 14:26
@Saadnajmi
refactor(deps): centralize per-package pnpm shims in packageExtensions
2a41152 
Move the per-package phantom-dependency declarations out of individual
package.json manifests and into a single packageExtensions block in .yarnrc.yml.
This reverts seven upstream-tracked manifests to pristine, confining the
pnpm-compat shims to the fork-only .yarnrc.yml so upstream merges stay clean.

Only third-party deps are moved. The fork's yarn.config.cjs constraints inspect
manifest deps and do not see packageExtensions entries; on release branches they
pin @react-native/* deps to the release version, so any @react-native/* dep must
remain in a manifest to stay governed. None of the moved deps are @react-native/*.

Moved:
- @react-native/codegen -> @babel/parser
- @react-native/babel-plugin-codegen -> @babel/plugin-syntax-flow
- @react-native/core-cli-utils -> metro
- @react-native/metro-babel-transformer -> metro-babel-transformer
- @react-native/compatibility-check -> invariant
- @react-native/eslint-plugin-monorepo -> hermes-estree
- @react-native/fantom -> jest-docblock, jest-message-util, metro, metro-config, source-map

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi
chore: address review feedback on pnpm PR
3435cb5 
- Revert the upstream-inherited yarn-install action and code-analysis-bot
  changes. Those files only serve the upstream Test All workflow, which the
  fork does not use for gating; the fork's PR workflow installs with
  'yarn install --immutable' and runs yarn lint/flow-check/format-check
  directly, so no changes to the upstream CI flow are needed.
- Trim the verbose docsite/.yarnrc.yml comment to a single line.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi
chore: minimize fork diff and tag [macOS] carve-outs
48ada00 
Audit of the pnpm branch to reduce divergence from upstream:

- Drop the ReactNativeApi.d.ts regeneration and the BuildApiSnapshot.js import-
  path normalization. The API snapshot is only validated by the upstream
  Test All workflow, which the fork does not use; its PR workflow never runs
  build-types --validate. Reverting them returns two files to pristine (-893).
- Shrink packages/rn-tester/metro.config.js to a single [macOS]-tagged line:
  keep upstream's 'metro-config' require and instead declare metro-config for
  @react-native/tester via packageExtensions, dropping the mergeConfig import
  rewrite.
- Tag the fork-only nodeLinker line with [macOS].
- Drop the [macOS] tag from the docsite .yarnrc.yml comment (config-only file).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi Saadnajmi changed the title chore: make the monorepo bundle under Yarn's pnpm linker chore: support Yarn's pnpm nodeLinker Jul 7, 2026
Saadnajmi
Saadnajmi commented Jul 7, 2026
View reviewed changes
Comment thread packages/rn-tester/metro.config.js Outdated
Saadnajmi
Saadnajmi commented Jul 7, 2026
View reviewed changes
Comment thread .flowconfig Outdated
@Saadnajmi
chore: address review - [macOS] start/end fence tags and yarn pnpm mo…
a8290e9 
…de wording

- Fence the .flowconfig name_mapper block and the .yarnrc.yml packageExtensions
  block with [macOS] / macOS] start/end tags per the fork convention.
- Reword the metro.config.js alias comment to use 'yarn pnpm mode' terminology.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi Saadnajmi mentioned this pull request Jul 7, 2026
Open
@Saadnajmi
fix: pin source-map to ^0.6.1 for fantom in yarn pnpm mode
c371d34 
Fantom uses the synchronous SourceMapConsumer constructor (the 0.6.x API);
source-map 0.7+ returns a Promise. The ^0.7.4 shim resolved fantom to 0.7.6,
which would break its stack-trace symbolication at runtime.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@Saadnajmi Saadnajmi merged commit 269455f into microsoft:main Jul 8, 2026
31 checks passed
@Saadnajmi Saadnajmi deleted the saadnajmi/yarn-pnpm-mode branch July 8, 2026 06:46
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