fix(react-native-host): fix community JSC support#3854
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Fix compile error in `ReactNativeHost.mm` when Hermes is not being used. `fatal error: 'ReactCommon/RCTHermesInstance.h' file not found` The `USE_HERMES` preprocessor definition was only being set in `GCC_PREPROCESSOR_DEFINITIONS` (for C and Objective-C files), but NOT in `CPP_PREPROCESSOR_DEFINITIONS` (for [Objective] C++) files. This caused `ReactNativeHost.mm` to NOT receive the `USE_HERMES=0` flag, making it incorrectly import Hermes symbols that aren't resolved at link time.
tido64
requested review from
JasonVMo,
Saadnajmi and
acoates-ms
as code owners
JasonVMo
approved these changes
Nov 12, 2025
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Description
Fix compile error in
ReactNativeHost.mmwhen Hermes is not being used.fatal error: 'ReactCommon/RCTHermesInstance.h' file not foundThe
USE_HERMESpreprocessor definition was only being set inGCC_PREPROCESSOR_DEFINITIONS(for C and Objective-C files), but NOT inCPP_PREPROCESSOR_DEFINITIONS(for [Objective] C++) files. This causedReactNativeHost.mmto NOT receive theUSE_HERMES=0flag, making it incorrectly import Hermes symbols that aren't resolved at link time.Supersedes #3845.
Test plan
See #3845.