Restore RCT_NEW_ARCH_ENABLED semantics for backward compatibility

packages/react-native-codegen/src/generators/components/GenerateThirdPartyFabricComponentsProviderH.js

@@ -35,11 +35,12 @@ extern "C" {
 #endif
 
 Class<RCTComponentViewProtocol> RCTThirdPartyFabricComponentsProvider(const char *name);
-
+#if RCT_NEW_ARCH_ENABLED
 #ifndef RCT_DYNAMIC_FRAMEWORKS
 
 ${lookupFuncs}
 
+#endif
 #endif
 
 #ifdef __cplusplus

packages/react-native-codegen/src/generators/components/GenerateThirdPartyFabricComponentsProviderObjCpp.js

@@ -34,9 +34,11 @@ const FileTemplate = ({lookupMap}: {lookupMap: string}) => `
 
 Class<RCTComponentViewProtocol> RCTThirdPartyFabricComponentsProvider(const char *name) {
   static std::unordered_map<std::string, Class (*)(void)> sFabricComponentsClassMap = {
+    #if RCT_NEW_ARCH_ENABLED
     #ifndef RCT_DYNAMIC_FRAMEWORKS
 ${lookupMap}
     #endif
+    #endif
   };
 
   auto p = sFabricComponentsClassMap.find(name);

packages/react-native-codegen/src/generators/components/__tests__/__snapshots__/GenerateThirdPartyFabricComponentsProviderH-test.js.snap

@@ -22,7 +22,7 @@ extern \\"C\\" {
 #endif
 
 Class<RCTComponentViewProtocol> RCTThirdPartyFabricComponentsProvider(const char *name);
-
+#if RCT_NEW_ARCH_ENABLED
 #ifndef RCT_DYNAMIC_FRAMEWORKS
 
 Class<RCTComponentViewProtocol> NoPropsNoEventsComponentCls(void) __attribute__((used)); // NO_PROPS_NO_EVENTS
@@ -57,6 +57,7 @@ Class<RCTComponentViewProtocol> ExcludedAndroidComponentCls(void) __attribute__(
 
 Class<RCTComponentViewProtocol> MultiFileIncludedNativeComponentCls(void) __attribute__((used)); // EXCLUDE_IOS_TWO_COMPONENTS_DIFFERENT_FILES
 
+#endif
 #endif
 
 #ifdef __cplusplus

packages/react-native-codegen/src/generators/components/__tests__/__snapshots__/GenerateThirdPartyFabricComponentsProviderObjCpp-test.js.snap

@@ -21,6 +21,7 @@ Map {
 
 Class<RCTComponentViewProtocol> RCTThirdPartyFabricComponentsProvider(const char *name) {
   static std::unordered_map<std::string, Class (*)(void)> sFabricComponentsClassMap = {
+    #if RCT_NEW_ARCH_ENABLED
     #ifndef RCT_DYNAMIC_FRAMEWORKS
 
     {\\"NoPropsNoEventsComponent\\", NoPropsNoEventsComponentCls}, // NO_PROPS_NO_EVENTS
@@ -82,6 +83,7 @@ Class<RCTComponentViewProtocol> RCTThirdPartyFabricComponentsProvider(const char
 
     {\\"MultiFileIncludedNativeComponent\\", MultiFileIncludedNativeComponentCls}, // EXCLUDE_IOS_TWO_COMPONENTS_DIFFERENT_FILES
     #endif
+    #endif
   };
 
   auto p = sFabricComponentsClassMap.find(name);

packages/react-native/Libraries/AppDelegate/RCTAppDelegate.mm

@@ -232,7 +232,7 @@ - (void)windowScene:(UIWindowScene *)windowScene
 
 - (BOOL)newArchEnabled
 {
-#if USE_NEW_ARCH
+#if RCT_NEW_ARCH_ENABLED
   return YES;
 #else
   return NO;

packages/react-native/Libraries/AppDelegate/React-RCTAppDelegate.podspec

@@ -19,11 +19,11 @@ end
 folly_flags = ' -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_CFG_NO_COROUTINES=1 -DFOLLY_HAVE_CLOCK_GETTIME=1'
 folly_compiler_flags = folly_flags + ' ' + '-Wno-comma -Wno-shorten-64-to-32'
 
-is_new_arch_enabled = ENV["USE_NEW_ARCH"] == "1"
+is_new_arch_enabled = ENV["RCT_NEW_ARCH_ENABLED"] == "1"
 use_hermes =  ENV['USE_HERMES'] == nil || ENV['USE_HERMES'] == '1'
 
-new_arch_enabled_flag = (is_new_arch_enabled ? " -DUSE_NEW_ARCH" : "")
-is_fabric_enabled = is_new_arch_enabled || ENV["RCT_FABRIC_ENABLED"]
+new_arch_enabled_flag = (is_new_arch_enabled ? " -DRCT_NEW_ARCH_ENABLED" : "")
+is_fabric_enabled = true #is_new_arch_enabled || ENV["RCT_FABRIC_ENABLED"]
 hermes_flag = (use_hermes ? " -DUSE_HERMES" : "")
 other_cflags = "$(inherited)" + folly_flags + new_arch_enabled_flag + hermes_flag
 

packages/react-native/scripts/cocoapods/__tests__/new_architecture-test.rb

@@ -87,12 +87,12 @@ def test_modifyFlagsForNewArch_whenOnOldArch_doNothing
         NewArchitectureHelper.modify_flags_for_new_architecture(installer, false)
 
         # Assert
-        assert_equal(first_xcconfig.attributes["OTHER_CPLUSPLUSFLAGS"], "$(inherited)")
-        assert_equal(first_xcconfig.save_as_invocation, [])
-        assert_equal(second_xcconfig.attributes["OTHER_CPLUSPLUSFLAGS"], "$(inherited)")
-        assert_equal(second_xcconfig.save_as_invocation, [])
-        assert_equal(react_core_debug_config.build_settings["OTHER_CPLUSPLUSFLAGS"], "$(inherited)")
-        assert_equal(react_core_release_config.build_settings["OTHER_CPLUSPLUSFLAGS"], "$(inherited)")
+        assert_equal(first_xcconfig.attributes["OTHER_CPLUSPLUSFLAGS"], "$(inherited) -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_CFG_NO_COROUTINES=1 -DFOLLY_HAVE_CLOCK_GETTIME=1 -Wno-comma -Wno-shorten-64-to-32")
+        assert_equal(first_xcconfig.save_as_invocation, ["a/path/First.xcconfig"])
+        assert_equal(second_xcconfig.attributes["OTHER_CPLUSPLUSFLAGS"], "$(inherited) -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_CFG_NO_COROUTINES=1 -DFOLLY_HAVE_CLOCK_GETTIME=1 -Wno-comma -Wno-shorten-64-to-32")
+        assert_equal(second_xcconfig.save_as_invocation, ["a/path/Second.xcconfig"])
+        assert_equal(react_core_debug_config.build_settings["OTHER_CPLUSPLUSFLAGS"], "$(inherited) -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_CFG_NO_COROUTINES=1 -DFOLLY_HAVE_CLOCK_GETTIME=1 -Wno-comma -Wno-shorten-64-to-32")
+        assert_equal(react_core_release_config.build_settings["OTHER_CPLUSPLUSFLAGS"], "$(inherited) -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_CFG_NO_COROUTINES=1 -DFOLLY_HAVE_CLOCK_GETTIME=1 -Wno-comma -Wno-shorten-64-to-32")
         assert_equal(yoga_debug_config.build_settings["OTHER_CPLUSPLUSFLAGS"], "$(inherited)")
         assert_equal(yoga_release_config.build_settings["OTHER_CPLUSPLUSFLAGS"], "$(inherited)")
     end

packages/react-native/scripts/cocoapods/codegen_utils.rb

@@ -72,7 +72,6 @@ def generate_react_codegen_podspec!(spec, codegen_output_dir, file_manager: File
     def get_react_codegen_spec(package_json_file, folly_version: get_folly_config()[:version], hermes_enabled: true, script_phases: nil, file_manager: File)
         package = JSON.parse(file_manager.read(package_json_file))
         version = package['version']
-        new_arch_disabled = ENV['RCT_NEW_ARCH_ENABLED'] != "1"
         use_frameworks = ENV['USE_FRAMEWORKS'] != nil
         folly_compiler_flags = '-DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_CFG_NO_COROUTINES=1 -DFOLLY_HAVE_CLOCK_GETTIME=1 -Wno-comma -Wno-shorten-64-to-32'
         boost_compiler_flags = '-Wno-documentation'

packages/react-native/scripts/cocoapods/new_architecture.rb

@@ -9,8 +9,6 @@
 require_relative "./helpers.rb"
 \
 class NewArchitectureHelper
-    @@new_arch_cpp_flags = " -DRCT_NEW_ARCH_ENABLED=1 #{Helpers::Constants.folly_config()[:compiler_flags]}"
-
     @@cplusplus_version = "c++20"
 
     @@NewArchWarningEmitted = false # Used not to spam warnings to the user.
@@ -42,26 +40,28 @@ def self.set_clang_cxx_language_standard_if_needed(installer)
         end
     end
 
+    def self.computeFlags(is_new_arch_enabled)
+        new_arch_flag = is_new_arch_enabled ? "-DRCT_NEW_ARCH_ENABLED=1 " : ""
+        return " #{new_arch_flag}#{Helpers::Constants.folly_config()[:compiler_flags]}"
+    end
+
     def self.modify_flags_for_new_architecture(installer, is_new_arch_enabled)
-        unless is_new_arch_enabled
-            return
-        end
-        # Add RCT_NEW_ARCH_ENABLED to Target pods xcconfig
+        # Add flags to Target pods xcconfig
         installer.aggregate_targets.each do |aggregate_target|
             aggregate_target.xcconfigs.each do |config_name, config_file|
-                ReactNativePodsUtils.add_flag_to_map_with_inheritance(config_file.attributes, "OTHER_CPLUSPLUSFLAGS", @@new_arch_cpp_flags)
+                ReactNativePodsUtils.add_flag_to_map_with_inheritance(config_file.attributes, "OTHER_CPLUSPLUSFLAGS", self.computeFlags(is_new_arch_enabled))
 
                 xcconfig_path = aggregate_target.xcconfig_path(config_name)
                 config_file.save_as(xcconfig_path)
             end
         end
 
-        # Add RCT_NEW_ARCH_ENABLED to generated pod target projects
+        # Add flags to Target pods xcconfig
         installer.target_installation_results.pod_target_installation_results.each do |pod_name, target_installation_result|
             # The React-Core pod may have a suffix added by Cocoapods, so we test whether 'React-Core' is a substring, and do not require exact match
             if pod_name.include? 'React-Core'
                 target_installation_result.native_target.build_configurations.each do |config|
-                    ReactNativePodsUtils.add_flag_to_map_with_inheritance(config.build_settings, "OTHER_CPLUSPLUSFLAGS", @@new_arch_cpp_flags)
+                    ReactNativePodsUtils.add_flag_to_map_with_inheritance(config.build_settings, "OTHER_CPLUSPLUSFLAGS", self.computeFlags(is_new_arch_enabled))
                 end
             end
         end
@@ -109,9 +109,8 @@ def self.install_modules_dependencies(spec, new_arch_enabled, folly_version = ge
         spec.dependency "RCT-Folly", folly_version
         spec.dependency "glog"
 
-        if new_arch_enabled
-            ReactNativePodsUtils.add_flag_to_map_with_inheritance(current_config, "OTHER_CPLUSPLUSFLAGS", @@new_arch_cpp_flags)
-        end
+
+        ReactNativePodsUtils.add_flag_to_map_with_inheritance(current_config, "OTHER_CPLUSPLUSFLAGS", self.computeFlags(new_arch_enabled))
 
         spec.dependency "React-RCTFabric" # This is for Fabric Component
         spec.dependency "React-Codegen"

packages/react-native/scripts/react_native_pods.rb

@@ -90,10 +90,9 @@ def use_react_native! (
   # Better to rely and enable this environment flag if the new architecture is turned on using flags.
   relative_path_from_current = Pod::Config.instance.installation_root.relative_path_from(Pathname.pwd)
   react_native_version = NewArchitectureHelper.extract_react_native_version(File.join(relative_path_from_current, path))
-  ENV['USE_NEW_ARCH'] = NewArchitectureHelper.compute_new_arch_enabled(new_arch_enabled, react_native_version)
+  ENV['RCT_NEW_ARCH_ENABLED'] = NewArchitectureHelper.compute_new_arch_enabled(new_arch_enabled, react_native_version)
   fabric_enabled = fabric_enabled || NewArchitectureHelper.new_arch_enabled
 
-  ENV['RCT_NEW_ARCH_ENABLED'] = "1"
   ENV['RCT_FABRIC_ENABLED'] = fabric_enabled ? "1" : "0"
   ENV['USE_HERMES'] = hermes_enabled ? "1" : "0"