[iOS][SPM] Stop re-creating library package roots on every sync by chrfalch · Pull Request #58597 · react/react-native

chrfalch · 2026-09-18T17:11:02Z

Summary

Building an app in Xcode fails when it autolinks a library that ships its own Package.swift, with one error per such library:

Missing package product 'reactnativeskia_ReactNativeSkia.ReactNativeSkia'
Missing package product 'reactnativesafeareacontext_ReactNativeSafeAreaContext.ReactNativeSafeAreaContext'

The same project builds fine from the command line. Two problems combine.

The sync destroys package roots Xcode has already loaded. Autolinking writes one symlink per self-managed library into build/generated/autolinking/libs/<Name>, and Xcode treats each as a local Swift package root. The generator deleted that whole directory and recreated it on every run, even when the generated output was byte-for-byte identical. Measured on a real app, across one no-op sync: the libs/ inode changed from 1913513750 to 1913930645, libs/ReactNativeSkia from 1913513937 to 1913930649, while the generated Package.swift kept the same MD5. Recreating a package root that Xcode has already resolved is what produces the error above.

Xcode's own bookkeeping made the sync run every time. The "Sync SPM Autolinking" build phase re-syncs when a watched input looks newer than its stamp, and it checked each library's whole directory with find <dir> -newer <stamp>. Xcode writes its per-user scheme state inside that directory, at <lib>/.swiftpm/xcode/xcuserdata/<user>.xcuserdatad/xcschemes/xcschememanagement.plist. So Xcode's own write marked the next build stale, which triggered the destructive re-sync, which broke that build. xcodebuild does not write that file, which is why command-line builds were never affected.

This change makes the libs/ tree idempotent — unchanged entries keep their inode, and entries that are no longer autolinked are pruned instead of wiped — and makes the staleness check skip .swiftpm.

How to verify

In an app that autolinks a library shipping its own Package.swift, build in Xcode twice in a row. Both builds should succeed. Before this change the second build fails with Missing package product.

Changelog:

[IOS][FIXED] - Stop SwiftPM autolinking from recreating library package roots on every sync, which broke Xcode builds of apps using libraries that ship their own Package.swift

Test Plan

Unit tests. yarn test packages/react-native/scripts/spm — 21 suites, 1009 tests pass.

New tests, written and seen failing before the fix:

Two consecutive generation runs over an unchanged self-managed dependency keep both the libs/ inode and each entry's inode. Failed before the fix with the same inode churn measured on the real app.
A dependency removed between two runs leaves no symlink under libs/.
The emitted staleness snippet is extracted from the generated script and executed under /bin/bash -c with set -euo pipefail against a temporary tree. A write under .swiftpm/ is ignored; a real source change is still detected.

Real app. A React Native 0.87.1 app on Xcode 27 autolinking @shopify/react-native-skia and react-native-safe-area-context, both self-managed. Before: xcodebuild succeeded, Xcode failed in about 5 seconds with the two errors above, on nearly every build.

Not run: the full CI matrix, and no Android-side check — this touches iOS SwiftPM tooling only.

Scope

Deliberately minimal.

One case still re-syncs: the first time Xcode creates .swiftpm inside a library, that bumps the library directory's own mtime, so the build after a fresh checkout reports stale once per library. That is harmless now that the sync is idempotent.

One related item is left alone: the aggregate Package.swift is still rewritten on every sync even when its content is unchanged, which bumps its mtime and can make Xcode re-resolve. That is wasteful but not destructive, and it is no longer reached on an ordinary IDE build now that .swiftpm writes do not mark the sync stale.

Autolinking writes one symlink per self-managed library into build/generated/autolinking/libs/<Name>, and Xcode holds each as a loaded local package root. The generator deleted and re-created that whole tree on every run, even when the generated output was byte-identical, so an Xcode build failed with "Missing package product" for every such library. The sync ran on every IDE build because its staleness check walked each library's directory with `find -newer`, and Xcode writes its own per-user scheme state under <lib>/.swiftpm. That write marked the next build stale, which triggered the destructive re-sync, which broke that build. Keep unchanged entries in place and prune only the ones that are no longer autolinked, and skip .swiftpm when probing for changes. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

meta-codesync · 2026-09-18T19:32:24Z

@shwanton has imported this pull request. If you are a Meta employee, you can view this in D120740029.

meta-codesync · 2026-09-22T14:01:59Z

@shwanton merged this pull request in 97cc934.

Summary: Building an app in Xcode fails when it autolinks a library that ships its own `Package.swift`, with one error per such library: ``` Missing package product 'reactnativeskia_ReactNativeSkia.ReactNativeSkia' Missing package product 'reactnativesafeareacontext_ReactNativeSafeAreaContext.ReactNativeSafeAreaContext' ``` The same project builds fine from the command line. Two problems combine. **The sync destroys package roots Xcode has already loaded.** Autolinking writes one symlink per self-managed library into `build/generated/autolinking/libs/<Name>`, and Xcode treats each as a local Swift package root. The generator deleted that whole directory and recreated it on every run, even when the generated output was byte-for-byte identical. Measured on a real app, across one no-op sync: the `libs/` inode changed from 1913513750 to 1913930645, `libs/ReactNativeSkia` from 1913513937 to 1913930649, while the generated `Package.swift` kept the same MD5. Recreating a package root that Xcode has already resolved is what produces the error above. **Xcode's own bookkeeping made the sync run every time.** The "Sync SPM Autolinking" build phase re-syncs when a watched input looks newer than its stamp, and it checked each library's whole directory with `find <dir> -newer <stamp>`. Xcode writes its per-user scheme state inside that directory, at `<lib>/.swiftpm/xcode/xcuserdata/<user>.xcuserdatad/xcschemes/xcschememanagement.plist`. So Xcode's own write marked the next build stale, which triggered the destructive re-sync, which broke that build. `xcodebuild` does not write that file, which is why command-line builds were never affected. This change makes the `libs/` tree idempotent — unchanged entries keep their inode, and entries that are no longer autolinked are pruned instead of wiped — and makes the staleness check skip `.swiftpm`. ### How to verify In an app that autolinks a library shipping its own `Package.swift`, build in Xcode twice in a row. Both builds should succeed. Before this change the second build fails with `Missing package product`. ## Changelog: [IOS][FIXED] - Stop SwiftPM autolinking from recreating library package roots on every sync, which broke Xcode builds of apps using libraries that ship their own Package.swift Pull Request resolved: #58597 Test Plan: **Unit tests.** `yarn test packages/react-native/scripts/spm` — 21 suites, 1009 tests pass. New tests, written and seen failing before the fix: - Two consecutive generation runs over an unchanged self-managed dependency keep both the `libs/` inode and each entry's inode. Failed before the fix with the same inode churn measured on the real app. - A dependency removed between two runs leaves no symlink under `libs/`. - The emitted staleness snippet is extracted from the generated script and executed under `/bin/bash -c` with `set -euo pipefail` against a temporary tree. A write under `.swiftpm/` is ignored; a real source change is still detected. **Real app.** A React Native 0.87.1 app on Xcode 27 autolinking `shopify/react-native-skia` and `react-native-safe-area-context`, both self-managed. Before: `xcodebuild` succeeded, Xcode failed in about 5 seconds with the two errors above, on nearly every build. **Not run:** the full CI matrix, and no Android-side check — this touches iOS SwiftPM tooling only. ## Scope Deliberately minimal. One case still re-syncs: the first time Xcode creates `.swiftpm` inside a library, that bumps the library directory's own mtime, so the build after a fresh checkout reports stale once per library. That is harmless now that the sync is idempotent. One related item is left alone: the aggregate `Package.swift` is still rewritten on every sync even when its content is unchanged, which bumps its mtime and can make Xcode re-resolve. That is wasteful but not destructive, and it is no longer reached on an ordinary IDE build now that `.swiftpm` writes do not mark the sync stale. Reviewed By: cipolleschi Differential Revision: D120740029 Pulled By: shwanton fbshipit-source-id: 3783d4cee4791ab13517d8f0dcac71f752cb7c1b (cherry picked from commit 97cc934)

Summary: Building an app in Xcode fails when it autolinks a library that ships its own `Package.swift`, with one error per such library: ``` Missing package product 'reactnativeskia_ReactNativeSkia.ReactNativeSkia' Missing package product 'reactnativesafeareacontext_ReactNativeSafeAreaContext.ReactNativeSafeAreaContext' ``` The same project builds fine from the command line. Two problems combine. **The sync destroys package roots Xcode has already loaded.** Autolinking writes one symlink per self-managed library into `build/generated/autolinking/libs/<Name>`, and Xcode treats each as a local Swift package root. The generator deleted that whole directory and recreated it on every run, even when the generated output was byte-for-byte identical. Measured on a real app, across one no-op sync: the `libs/` inode changed from 1913513750 to 1913930645, `libs/ReactNativeSkia` from 1913513937 to 1913930649, while the generated `Package.swift` kept the same MD5. Recreating a package root that Xcode has already resolved is what produces the error above. **Xcode's own bookkeeping made the sync run every time.** The "Sync SPM Autolinking" build phase re-syncs when a watched input looks newer than its stamp, and it checked each library's whole directory with `find <dir> -newer <stamp>`. Xcode writes its per-user scheme state inside that directory, at `<lib>/.swiftpm/xcode/xcuserdata/<user>.xcuserdatad/xcschemes/xcschememanagement.plist`. So Xcode's own write marked the next build stale, which triggered the destructive re-sync, which broke that build. `xcodebuild` does not write that file, which is why command-line builds were never affected. This change makes the `libs/` tree idempotent — unchanged entries keep their inode, and entries that are no longer autolinked are pruned instead of wiped — and makes the staleness check skip `.swiftpm`. ### How to verify In an app that autolinks a library shipping its own `Package.swift`, build in Xcode twice in a row. Both builds should succeed. Before this change the second build fails with `Missing package product`. ## Changelog: [IOS][FIXED] - Stop SwiftPM autolinking from recreating library package roots on every sync, which broke Xcode builds of apps using libraries that ship their own Package.swift Pull Request resolved: react#58597 Test Plan: **Unit tests.** `yarn test packages/react-native/scripts/spm` — 21 suites, 1009 tests pass. New tests, written and seen failing before the fix: - Two consecutive generation runs over an unchanged self-managed dependency keep both the `libs/` inode and each entry's inode. Failed before the fix with the same inode churn measured on the real app. - A dependency removed between two runs leaves no symlink under `libs/`. - The emitted staleness snippet is extracted from the generated script and executed under `/bin/bash -c` with `set -euo pipefail` against a temporary tree. A write under `.swiftpm/` is ignored; a real source change is still detected. **Real app.** A React Native 0.87.1 app on Xcode 27 autolinking `shopify/react-native-skia` and `react-native-safe-area-context`, both self-managed. Before: `xcodebuild` succeeded, Xcode failed in about 5 seconds with the two errors above, on nearly every build. **Not run:** the full CI matrix, and no Android-side check — this touches iOS SwiftPM tooling only. ## Scope Deliberately minimal. One case still re-syncs: the first time Xcode creates `.swiftpm` inside a library, that bumps the library directory's own mtime, so the build after a fresh checkout reports stale once per library. That is harmless now that the sync is idempotent. One related item is left alone: the aggregate `Package.swift` is still rewritten on every sync even when its content is unchanged, which bumps its mtime and can make Xcode re-resolve. That is wasteful but not destructive, and it is no longer reached on an ordinary IDE build now that `.swiftpm` writes do not mark the sync stale. Reviewed By: cipolleschi Differential Revision: D120740029 Pulled By: shwanton fbshipit-source-id: 3783d4cee4791ab13517d8f0dcac71f752cb7c1b (cherry picked from commit 97cc934)

Summary: Recent fixes to the iOS SwiftPM tooling (`scripts/spm`) all fixed bugs that CI did not catch. Adopters found them first. Each fix added a test for its own bug only. The bugs fall into a few classes: output that changes when nothing changed, generated names that collide or do not resolve, values that are hard-coded instead of read from the app, machine-specific paths in files that users commit, and malformed files that Xcode tolerates. This PR adds two test-only tools that look for each class in general. They run in the existing Linux Jest job (`test_js`). No production code changes. 1. **Invariant checker** (`spm-invariants.js`, not a test file itself). It reads the files that the tooling generates and returns a list of violations: - no machine paths (temp dir, `$HOME`, absolute build-setting values) in `project.pbxproj`, `.xcscheme`, or `.spm-injected.json`; - the scheme parses as XML, and the pre-action script keeps its line breaks; - in every generated `Package.swift`, target and product names are unique (also case-insensitive) and valid C99 identifiers, and every dependency resolves, including products of local `.package(path:)` dependencies; - every generated or scaffolded manifest uses the app's iOS deployment target; the codegen manifest, whose template fixes `.iOS(.v15)`, must not be above it; - `project.pbxproj` is balanced, every referenced object ID is defined, and the frameworks in `.spm-injected.json` match the project. Each rule also fails when the file or field it checks is missing, so a check cannot pass by finding nothing. 2. **Lifecycle test** (`spm-lifecycle-test.js` + `spm-fixture-app.js`). It builds a fake app on disk (deployment target 16.4), fake prebuilt artifacts for two React Native versions, and four fake libraries: one with its own `Package.swift`, one podspec-only library with `module_name` different from its npm name, one scoped `acme/…` package, and one autolinking plugin with a flavored framework. It then runs `scaffold → add → sync → sync → update (same version) → update (next version) → deinit` through `setup-apple-spm.js`, and runs the checker after each step. It also asserts: - a second sync changes no byte and replaces no `libs/` entry; - the build-time stale check reacts to the right changes and ignores files that Xcode writes; - a plugin framework mismatch makes sync exit with code 2; - `update` to the same version and `deinit` restore the project and scheme byte for byte. Network access, `plutil`, `otool`, codegen and `pod` are mocked, so the test runs offline on Linux. ## Changelog: [INTERNAL] [ADDED] - Add regression tests for the iOS SwiftPM tooling Pull Request resolved: #59217 Test Plan: ``` yarn jest --no-cache -i packages/react-native/scripts/spm/__tests__ ``` Result: 24 suites, 1124 tests, all passed, about 23 s (on main at dd9b6c5). The two new suites take about 4 s. Each earlier fix was undone one at a time with `git show <sha> -- ':!**/__tests__/**' | git apply -R`, and the new tests failed each time: | Fix reverted | New tests failing | |---|---| | #58826 (scheme pre-action newlines) | 9 | | #58292 (absolute `HERMES_CLI_PATH` in pbxproj) | 9 | | #58597 (`libs/` rewritten on every sync) | 2 | | #58828 (watched path absent at add time) | 1 | `yarn eslint` and `prettier --check` on the new files: clean. Not run: Linux locally. The `test_js` job on this PR is the first Linux run. Reviewed By: cortinico Differential Revision: D126304581 Pulled By: cipolleschi fbshipit-source-id: c1bacf9ef2c6955a262cac0053491d69535375e9

Summary: Recent fixes to the iOS SwiftPM tooling (`scripts/spm`) all fixed bugs that CI did not catch. Adopters found them first. Each fix added a test for its own bug only. The bugs fall into a few classes: output that changes when nothing changed, generated names that collide or do not resolve, values that are hard-coded instead of read from the app, machine-specific paths in files that users commit, and malformed files that Xcode tolerates. This PR adds two test-only tools that look for each class in general. They run in the existing Linux Jest job (`test_js`). No production code changes. 1. **Invariant checker** (`spm-invariants.js`, not a test file itself). It reads the files that the tooling generates and returns a list of violations: - no machine paths (temp dir, `$HOME`, absolute build-setting values) in `project.pbxproj`, `.xcscheme`, or `.spm-injected.json`; - the scheme parses as XML, and the pre-action script keeps its line breaks; - in every generated `Package.swift`, target and product names are unique (also case-insensitive) and valid C99 identifiers, and every dependency resolves, including products of local `.package(path:)` dependencies; - every generated or scaffolded manifest uses the app's iOS deployment target; the codegen manifest, whose template fixes `.iOS(.v15)`, must not be above it; - `project.pbxproj` is balanced, every referenced object ID is defined, and the frameworks in `.spm-injected.json` match the project. Each rule also fails when the file or field it checks is missing, so a check cannot pass by finding nothing. 2. **Lifecycle test** (`spm-lifecycle-test.js` + `spm-fixture-app.js`). It builds a fake app on disk (deployment target 16.4), fake prebuilt artifacts for two React Native versions, and four fake libraries: one with its own `Package.swift`, one podspec-only library with `module_name` different from its npm name, one scoped `acme/…` package, and one autolinking plugin with a flavored framework. It then runs `scaffold → add → sync → sync → update (same version) → update (next version) → deinit` through `setup-apple-spm.js`, and runs the checker after each step. It also asserts: - a second sync changes no byte and replaces no `libs/` entry; - the build-time stale check reacts to the right changes and ignores files that Xcode writes; - a plugin framework mismatch makes sync exit with code 2; - `update` to the same version and `deinit` restore the project and scheme byte for byte. Network access, `plutil`, `otool`, codegen and `pod` are mocked, so the test runs offline on Linux. ## Changelog: [INTERNAL] [ADDED] - Add regression tests for the iOS SwiftPM tooling Pull Request resolved: #59217 Test Plan: ``` yarn jest --no-cache -i packages/react-native/scripts/spm/__tests__ ``` Result: 24 suites, 1124 tests, all passed, about 23 s (on main at dd9b6c5). The two new suites take about 4 s. Each earlier fix was undone one at a time with `git show <sha> -- ':!**/__tests__/**' | git apply -R`, and the new tests failed each time: | Fix reverted | New tests failing | |---|---| | #58826 (scheme pre-action newlines) | 9 | | #58292 (absolute `HERMES_CLI_PATH` in pbxproj) | 9 | | #58597 (`libs/` rewritten on every sync) | 2 | | #58828 (watched path absent at add time) | 1 | `yarn eslint` and `prettier --check` on the new files: clean. Not run: Linux locally. The `test_js` job on this PR is the first Linux run. Reviewed By: cortinico Differential Revision: D126304581 Pulled By: cipolleschi fbshipit-source-id: c1bacf9ef2c6955a262cac0053491d69535375e9 (cherry picked from commit fba55e2)

Summary: Recent fixes to the iOS SwiftPM tooling (`scripts/spm`) all fixed bugs that CI did not catch. Adopters found them first. Each fix added a test for its own bug only. The bugs fall into a few classes: output that changes when nothing changed, generated names that collide or do not resolve, values that are hard-coded instead of read from the app, machine-specific paths in files that users commit, and malformed files that Xcode tolerates. This PR adds two test-only tools that look for each class in general. They run in the existing Linux Jest job (`test_js`). No production code changes. 1. **Invariant checker** (`spm-invariants.js`, not a test file itself). It reads the files that the tooling generates and returns a list of violations: - no machine paths (temp dir, `$HOME`, absolute build-setting values) in `project.pbxproj`, `.xcscheme`, or `.spm-injected.json`; - the scheme parses as XML, and the pre-action script keeps its line breaks; - in every generated `Package.swift`, target and product names are unique (also case-insensitive) and valid C99 identifiers, and every dependency resolves, including products of local `.package(path:)` dependencies; - every generated or scaffolded manifest uses the app's iOS deployment target; the codegen manifest, whose template fixes `.iOS(.v15)`, must not be above it; - `project.pbxproj` is balanced, every referenced object ID is defined, and the frameworks in `.spm-injected.json` match the project. Each rule also fails when the file or field it checks is missing, so a check cannot pass by finding nothing. 2. **Lifecycle test** (`spm-lifecycle-test.js` + `spm-fixture-app.js`). It builds a fake app on disk (deployment target 16.4), fake prebuilt artifacts for two React Native versions, and four fake libraries: one with its own `Package.swift`, one podspec-only library with `module_name` different from its npm name, one scoped `acme/…` package, and one autolinking plugin with a flavored framework. It then runs `scaffold → add → sync → sync → update (same version) → update (next version) → deinit` through `setup-apple-spm.js`, and runs the checker after each step. It also asserts: - a second sync changes no byte and replaces no `libs/` entry; - the build-time stale check reacts to the right changes and ignores files that Xcode writes; - a plugin framework mismatch makes sync exit with code 2; - `update` to the same version and `deinit` restore the project and scheme byte for byte. Network access, `plutil`, `otool`, codegen and `pod` are mocked, so the test runs offline on Linux. ## Changelog: [INTERNAL] [ADDED] - Add regression tests for the iOS SwiftPM tooling Pull Request resolved: react#59217 Test Plan: ``` yarn jest --no-cache -i packages/react-native/scripts/spm/__tests__ ``` Result: 24 suites, 1124 tests, all passed, about 23 s (on main at dd9b6c5). The two new suites take about 4 s. Each earlier fix was undone one at a time with `git show <sha> -- ':!**/__tests__/**' | git apply -R`, and the new tests failed each time: | Fix reverted | New tests failing | |---|---| | react#58826 (scheme pre-action newlines) | 9 | | react#58292 (absolute `HERMES_CLI_PATH` in pbxproj) | 9 | | react#58597 (`libs/` rewritten on every sync) | 2 | | react#58828 (watched path absent at add time) | 1 | `yarn eslint` and `prettier --check` on the new files: clean. Not run: Linux locally. The `test_js` job on this PR is the first Linux run. Reviewed By: cortinico Differential Revision: D126304581 Pulled By: cipolleschi fbshipit-source-id: c1bacf9ef2c6955a262cac0053491d69535375e9 (cherry picked from commit fba55e2)

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chrfalch requested a review from cipolleschi September 18, 2026 17:25

meta-codesync Bot closed this in 97cc934 Sep 22, 2026

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chrfalch mentioned this pull request Sep 22, 2026

[0.88] Stop re-creating library package roots on every sync reactwg/react-native-releases#1421

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chrfalch mentioned this pull request Oct 20, 2026

Add regression tests for the iOS SwiftPM tooling #59217

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This was referenced Oct 26, 2026

[0.87] Stop re-creating library package roots on every sync #59500

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[0.87] Encode line breaks in SwiftPM scheme pre-action scriptText #59501

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[0.87] Re-sync SwiftPM autolinking when a watched path appears #59502

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[iOS][SPM] Stop re-creating library package roots on every sync - #58597

[iOS][SPM] Stop re-creating library package roots on every sync#58597
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