Write the prebuilt module-map flag to OTHER_CPLUSPLUSFLAGS too - #57742
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`ReactNativeCoreUtils.add_prebuilt_header_search_paths` activates the prebuilt ReactNativeHeaders module map by injecting `-fmodule-map-file=...` into `OTHER_CFLAGS` and `OTHER_SWIFT_FLAGS`, but not `OTHER_CPLUSPLUSFLAGS`. C++ and ObjC++ translation units therefore lose modular resolution of the relocated `react/`, `yoga/` and `RCTDeprecation/` namespaces. This is a regression against the VFS implementation this replaced (0.86's `add_vfs_overlay_flags`), which wrote all three compiler-flag keys. Xcode's `OTHER_CPLUSPLUSFLAGS = $(OTHER_CFLAGS)` default does not cover for it, because React Native sets that key explicitly at several sites (`new_architecture.rb`, plus `pod_target_xcconfig` in ReactCodegen, React-RCTAppDelegate and React-RCTAnimatedModuleProvider) and an explicit value replaces the C-flags default for every C++ TU. Co-Authored-By: Claude Opus 5 <[email protected]>
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Summary:
add_prebuilt_header_search_paths(scripts/cocoapods/rncore.rb) injects the prebuilt ReactNativeHeaders module map intoOTHER_CFLAGSandOTHER_SWIFT_FLAGS, but notOTHER_CPLUSPLUSFLAGS. C++ and ObjC++ translation units therefore lose modular resolution of the relocatedreact/,yoga/andRCTDeprecation/namespaces.This is a regression: 0.86's VFS implementation (
add_vfs_overlay_flags) wrote all three compiler-flag keys, the modular rewrite writes two. This adds the third back, reusing the existing quotedmodule_map_flag.Xcode's
OTHER_CPLUSPLUSFLAGS = $(OTHER_CFLAGS)default doesn't cover for it, because an explicit value replaces the C flags instead of merging — and React Native sets the key explicitly, both innew_architecture.rband in thepod_target_xcconfigof ReactCodegen, React-RCTAppDelegate and React-RCTAnimatedModuleProvider.To be clear about what this is: a correctness fix, not a bug fix. No build fails today, because
HEADER_SEARCH_PATHSis injected unconditionally and the includes still resolve textually. What is lost is modular resolution.Changelog:
[IOS] [FIXED] - Write the prebuilt module-map flag to
OTHER_CPLUSPLUSFLAGSso C++/ObjC++ sources resolve the relocated namespaces modularlyTest Plan:
On an app using the prebuilt RNCore (
RCT_USE_PREBUILT_RNCORE=1, artifacts from Maven), counting pods whose xcconfig carries the module-map flag per key:OTHER_CFLAGSOTHER_CPLUSPLUSFLAGSOTHER_SWIFT_FLAGSxcodebuildsucceeds after the change (** BUILD SUCCEEDED **, 0 errors), so the flag is accepted byScanDependenciesand the explicit-module precompile. This was a static-library build; framework linkage was not exercised.🤖 Generated with Claude Code