[build-tools] - support Xcode DerivedData pod products caching for iOS builds by AbbanMustafa · Pull Request #3491 · expo/eas-cli

AbbanMustafa · 2026-03-10T19:14:36Z

Why

iOS builds currently recompile all CocoaPods from scratch on every build. Unlike local development where Xcode's DerivedData persists compiled products between builds, CI builds start with a clean DerivedData every time.

The xcodebuild step spends the majority of its time rebuilding pod dependencies that haven't changed between builds. This adds Xcode build product caching to skip that redundant recompilation. Gated behind EAS_XCODE_CACHE=1.

How

Cache pre-built pod products (.a l ibraries, .modulemap files, headers) from DerivedData after a successful build, keyed by lockfile hash. On subsequent builds, restore the cached products and patch the Xcodeproject to skip pod recompilation.

Restore (RESTORE_CACHE): Extract cached products to /tmp/pods-cache/ and rewrite absolute paths in .modulemap files. Products live outside DerivedData because xcodebuild archive wipes ArchiveIntermediates/ at the start of each run.

Patch (INSTALL_PODS, after pod install): Placing pre-built products on disk isn't enough. Xcode still sees pod targets in Pods.xcodeproj and will rebuild them. Provide a Ruby script removes non-umbrella pod targets from
the project entirely, then patches PODS_CONFIGURATION_BUILD_DIR in the xcconfig files to point at /tmp/pods-cache/ so the linker resolves to cached .a files instead of empty DerivedData.

Save (SAVE_CACHE): Locate build products in ArchiveIntermediates/.../BuildProductsPath/Release-* (archive) or Build/Products/Release-* (simulator) and upload. derived_data_path is set to ./build in the Gymfile so
products land in a known location. Each save replaces the entire cache, so stale products from removed pods are naturally pruned.

Cache key is ios-xcode-cache-{device|sim}-{lockfile_hash} — separate keys for device (Release-iphoneos, arm64) and simulator (Debug-iphonesimulator, x86_64/arm64) builds to prevent architecture mismatches.

Performance: Archive builds go from 🙌~3 min to ~30 sec on cache hit (6x speedup)🙌

Test Plan

Ran iOS archive build with XCODE_CACHE=1 — first build misses, saves cache after completion
Ran second build — cache hit, pod targets removed from xcodeproj, xcodebuild skips recompilation
Ran simulator build — uses separate sim cache key, no architecture mismatch with device cache
Ran without XCODE_CACHE=1 — all cache phases no-op
Verified modulemap paths are correctly rewritten to /tmp/pods-cache/

github-actions · 2026-03-17T07:04:11Z

Subscribed to pull request

File Patterns	Mentions
*/	@douglowder

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codecov · 2026-03-17T07:11:41Z

Codecov Report

❌ Patch coverage is 12.75168% with 130 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.44%. Comparing base (f3fd05d) to head (fef31f7).
⚠️ Report is 17 commits behind head on main.

Files with missing lines	Patch %	Lines
...ild-tools/src/steps/functions/restoreBuildCache.ts	10.98%	73 Missing ⚠️
.../build-tools/src/steps/functions/saveBuildCache.ts	7.70%	48 Missing ⚠️
packages/build-tools/src/utils/xcodeCacheKey.ts	42.86%	8 Missing ⚠️
...ages/build-tools/src/steps/functionGroups/build.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3491      +/-   ##
==========================================
+ Coverage   53.39%   53.44%   +0.06%     
==========================================
  Files         813      816       +3     
  Lines       34438    34783     +345     
  Branches     7151     7217      +66     
==========================================
+ Hits        18384    18587     +203     
- Misses      15972    16115     +143     
+ Partials       82       81       -1

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github-actions · 2026-03-18T06:17:07Z

⏩ The changelog entry check has been skipped since the "no changelog" label is present.

AbbanMustafa · 2026-03-18T06:20:45Z

sjchmiela

Did you see / try:

Can you please add comments explaining the logic / subjects / actions the code is doing? There's a lot to understand here and magic prefixes and everything and making it clearer will also maybe make it clearer to review

sjchmiela · 2026-03-18T15:13:08Z

packages/build-tools/src/utils/xcodeCacheKey.ts

+
+export async function generateXcodeCacheKeyAsync(
+  workingDirectory: string,
+  simulator?: boolean


Is simulator cache helpful for device build and/or vice versa? It seems it's not based on PR descirption. Let's make the parameter required and an inline enumerator "simulator" | "device" or sth like that.

sjchmiela · 2026-03-18T15:14:47Z

packages/build-tools/src/utils/xcodeCacheKey.ts

+
+import { findPackagerRootDir } from './packageManager';
+
+export const XCODE_CACHE_KEY_PREFIX = 'ios-xcode-cache-';


Let's not export it like that if it should never restore "just" ios-xcode-cache- cache?

sjchmiela · 2026-03-18T15:23:24Z

packages/build-tools/src/steps/functions/restoreBuildCache.ts

+  logger.info(`Rewrote paths in ${patchCount} modulemap files`);
+}
+
+const PATCH_RUBY_SCRIPT = `


Is this achievable using Expo config plugins code?

sjchmiela · 2026-03-18T15:40:53Z

I'll also let myself add @lukmccall as a reviewer — he has much more experience in the area.

I also wonder how does https://github.com/software-mansion/rnrepo do it for the recently added iOS support. If this pull request's main thing is to cache Pod artifacts and they do build Pod artifacts for reuse…

lukmccall

Are we sure that we're not leaking any personal information by caching DerivedData? I'm not sure if this directory was intended to be cached.

lukmccall · 2026-03-19T13:11:19Z

packages/build-tools/src/utils/xcodeCacheKey.ts

+  const variant = simulator ? 'sim' : 'device';
+
+  try {
+    return `${XCODE_CACHE_KEY_PREFIX}${variant}-${hashFiles([lockPath])}`;


The lockfile probably doesn't change if we change the XCode version. So, we probably need to include it in the key.

lukmccall · 2026-03-19T13:13:37Z

packages/build-tools/src/steps/functions/restoreBuildCache.ts

+const PATCH_RUBY_SCRIPT = `
+require 'xcodeproj'
+
+project = Xcodeproj::Project.open('ios/Pods/Pods.xcodeproj')


Consider searching for the xcodeproj rather than relying on the hardcoded path.

sjchmiela · 2026-03-19T15:36:49Z

Are we sure that we're not leaking any personal information by caching DerivedData? I'm not sure if this directory was intended to be cached.

Oh so this is not going to be public, this cache is scoped per-app

AbbanMustafa added 6 commits March 10, 2026 14:13

derived data cache

10c148a

run build phases

6090749

proper path

b6450b2

proper path

d68a7fa

derived_data_path to the archive Gymfile template

9aeaba4

archive & simulator build support

8671d26

AbbanMustafa added the no changelog PR that doesn't require a changelog entry label Mar 16, 2026

AbbanMustafa added 2 commits March 17, 2026 01:31

cleanup

94bf1ca

cleanup

8a9bc57

AbbanMustafa changed the title ~~derived data cache~~ [build-tools] - support Xcode DerivedData pod products caching for iOS builds Mar 17, 2026

AbbanMustafa added 2 commits March 17, 2026 01:51

snapshots

c5a12d9

cleanup

aa77ef6

AbbanMustafa marked this pull request as ready for review March 17, 2026 07:03

fold into existing restore/save_build_cache

fef31f7

AbbanMustafa requested a review from sjchmiela March 18, 2026 06:48

sjchmiela reviewed Mar 18, 2026

View reviewed changes

sjchmiela requested a review from lukmccall March 18, 2026 15:40

lukmccall reviewed Mar 19, 2026

View reviewed changes


		import { findPackagerRootDir } from './packageManager';

		export const XCODE_CACHE_KEY_PREFIX = 'ios-xcode-cache-';

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Why

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Performance: Archive builds go from 🙌~3 min to ~30 sec on cache hit (6x speedup)🙌

Test Plan

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AbbanMustafa commented Mar 10, 2026 •

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