fix(ios): make Podfile.lock SPEC CHECKSUMS deterministic across machines

[IsaacIsrael]

Summary

Two sources of non-determinism cause Podfile.lock SPEC CHECKSUMS to differ between machines, breaking pod install --deployment in CI and creating unnecessary churn in PRs.

Fix 1: Sort Dir.glob results in Yoga.podspec

Dir.glob returns files in filesystem-dependent order (varies across macOS APFS volumes, case sensitivity settings, and Linux ext4/xfs). Since CocoaPods evaluates the podspec at install time, the resulting array order differs between machines, producing different spec checksums.

# Before
spec.private_header_files = Dir.glob(all_header_files) - Dir.glob(public_header_files)

# After
spec.private_header_files = Dir.glob(all_header_files).sort - Dir.glob(public_header_files).sort

Fix 2: Use Pods-relative path in hermes-engine.podspec

require.resolve with __dir__ resolves to an absolute path containing the developer's home directory (e.g., /Users/alice/project/node_modules/...). This absolute path gets baked into user_target_xcconfig, which differs per machine.

Replaced with $(PODS_ROOT)/../../node_modules/hermes-compiler/hermesc/osx-bin/hermesc — a Pods-relative Xcode build variable that resolves at build time instead of pod install time.

Changelog:

[IOS] [FIXED] - Make Podfile.lock SPEC CHECKSUMS deterministic across machines by sorting Dir.glob results in Yoga.podspec and using a Pods-relative path in hermes-engine.podspec

Test Plan

1. Run pod install on machine A, record Podfile.lock
2. Run pod install on machine B (different username/home directory)
3. Verify SPEC CHECKSUMS are identical between both runs

We have verified this fix in our production app — after patching, running pod install consecutively produces zero diff in Podfile.lock.

Fixes #56975

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[meta-codesync]

@fabriziocucci has imported this pull request. If you are a Meta employee, you can view this in D106499747.

[cipolleschi]

his won't work with RNTester because RNTester doesn't have an iOS folder. This assumes that the structure is always:

app
|-> node_modules
|-> ios
    |-> Pods

But many apps might have different setups and layouts.