Create script to automatically set CLANG_CXX_LANGUAGE_STANDARD on the client project

React-Core.podspec

@@ -47,7 +47,7 @@ Pod::Spec.new do |s|
   s.compiler_flags         = folly_compiler_flags + ' ' + boost_compiler_flags
   s.header_dir             = "React"
   s.framework              = "JavaScriptCore"
-  s.pod_target_xcconfig    = { "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)/ReactCommon\" \"$(PODS_ROOT)/boost\" \"$(PODS_ROOT)/DoubleConversion\" \"$(PODS_ROOT)/RCT-Folly\" \"${PODS_ROOT}/Headers/Public/React-hermes\" \"${PODS_ROOT}/Headers/Public/hermes-engine\" \"${PODS_ROOT}/Headers/Public/FlipperKit\" \"$(PODS_ROOT)/Headers/Public/ReactCommon\" \"$(PODS_ROOT)/Headers/Public/React-RCTFabric\"", "DEFINES_MODULE" => "YES", "GCC_PREPROCESSOR_DEFINITIONS" => "RCT_METRO_PORT=${RCT_METRO_PORT}" }
+  s.pod_target_xcconfig    = { "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)/ReactCommon\" \"$(PODS_ROOT)/boost\" \"$(PODS_ROOT)/DoubleConversion\" \"$(PODS_ROOT)/RCT-Folly\" \"${PODS_ROOT}/Headers/Public/React-hermes\" \"${PODS_ROOT}/Headers/Public/hermes-engine\" \"${PODS_ROOT}/Headers/Public/FlipperKit\" \"$(PODS_ROOT)/Headers/Public/ReactCommon\" \"$(PODS_ROOT)/Headers/Public/React-RCTFabric\"", "DEFINES_MODULE" => "YES", "GCC_PREPROCESSOR_DEFINITIONS" => "RCT_METRO_PORT=${RCT_METRO_PORT}", "CLANG_CXX_LANGUAGE_STANDARD" => "c++17" }
   s.user_target_xcconfig   = { "HEADER_SEARCH_PATHS" => "\"$(PODS_ROOT)/Headers/Private/React-Core\""}
   s.default_subspec        = "Default"
 

package.json

@@ -56,6 +56,7 @@
     "scripts/cocoapods/codegen.rb",
     "scripts/cocoapods/fabric.rb",
     "scripts/cocoapods/flipper.rb",
+    "scripts/cocoapods/new_architecture.rb",
     "scripts/react-native-xcode.sh",
     "sdks/hermes-engine",
     "sdks/hermesc",

packages/rn-tester/Podfile

@@ -1,4 +1,5 @@
 require_relative '../../scripts/react_native_pods'
+require_relative '../../scripts/cocoapods/new_architecture'
 
 source 'https://cdn.cocoapods.org/'
 platform :ios, '12.4'
@@ -65,4 +66,5 @@ end
 post_install do |installer|
   react_native_post_install(installer, @prefix_path)
   __apply_Xcode_12_5_M1_post_install_workaround(installer)
+  set_clang_cxx_language_standard_if_needed(installer)
 end

packages/rn-tester/RNTesterPods.xcodeproj/project.pbxproj

@@ -843,7 +843,7 @@
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
-				CLANG_CXX_LANGUAGE_STANDARD = "gnu++17";
+				CLANG_CXX_LANGUAGE_STANDARD = "c++17";
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
@@ -913,6 +913,7 @@
 					"-ObjC",
 					"-lc++",
 				);
+				REACT_NATIVE_PATH = "${PODS_ROOT}/../../..";
 				SDKROOT = iphoneos;
 				WARNING_CFLAGS = (
 					"-Wextra",
@@ -927,7 +928,7 @@
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
-				CLANG_CXX_LANGUAGE_STANDARD = "gnu++17";
+				CLANG_CXX_LANGUAGE_STANDARD = "c++17";
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
@@ -989,6 +990,7 @@
 					"-ObjC",
 					"-lc++",
 				);
+				REACT_NATIVE_PATH = "${PODS_ROOT}/../../..";
 				SDKROOT = iphoneos;
 				VALIDATE_PRODUCT = YES;
 				WARNING_CFLAGS = (

scripts/cocoapods/__tests__/new_architecture-test.rb

@@ -0,0 +1,133 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+require "test/unit"
+require_relative "../new_architecture.rb"
+require_relative "./test_utils/InstallerMock.rb"
+require_relative "./test_utils/PodMock.rb"
+
+class NewArchitectureTests < Test::Unit::TestCase
+    def setup
+        File.enable_testing_mode!
+    end
+
+    def teardown
+        Pod::UI.reset()
+    end
+
+
+    def test_setClangCxxLanguageStandardIfNeeded_whenReactCoreIsPresent
+        installer = prepare_mocked_installer_with_react_core
+        set_clang_cxx_language_standard_if_needed(installer)
+
+        assert_equal(installer.aggregate_targets[0].user_project.build_configurations[0].build_settings["CLANG_CXX_LANGUAGE_STANDARD"], "c++17")
+        assert_equal(installer.aggregate_targets[1].user_project.build_configurations[0].build_settings["CLANG_CXX_LANGUAGE_STANDARD"], "c++17")
+        assert_equal(installer.pods_project.targets[1].received_resolved_build_setting_parameters, [ReceivedCommonResolvedBuildSettings.new("CLANG_CXX_LANGUAGE_STANDARD", true)])
+        assert_equal(Pod::UI.collected_messages, ["Setting CLANG_CXX_LANGUAGE_STANDARD to c++17 on /test/path.xcproj", "Setting CLANG_CXX_LANGUAGE_STANDARD to c++17 on /test/path2.xcproj"])
+    end
+
+    def test_setClangCxxLanguageStandardIfNeeded_whenReactCoreIsNotPresent
+        installer = prepare_mocked_installer_without_react_core
+        set_clang_cxx_language_standard_if_needed(installer)
+
+        assert_equal(installer.aggregate_targets[0].user_project.build_configurations[0].build_settings["CLANG_CXX_LANGUAGE_STANDARD"], nil)
+        assert_equal(installer.aggregate_targets[1].user_project.build_configurations[0].build_settings["CLANG_CXX_LANGUAGE_STANDARD"], nil)
+        assert_equal(installer.pods_project.targets[0].received_resolved_build_setting_parameters, [])
+        assert_equal(Pod::UI.collected_messages, [])
+    end
+
+    def test_setClangCxxLanguageStandardIfNeeded_whenThereAreDifferentValuesForLanguageStandard_takesTheFirstValue
+        installer = prepare_mocked_installer_with_react_core_and_different_language_standards
+        set_clang_cxx_language_standard_if_needed(installer)
+
+        assert_equal(installer.aggregate_targets[0].user_project.build_configurations[0].build_settings["CLANG_CXX_LANGUAGE_STANDARD"], "c++17")
+        assert_equal(installer.aggregate_targets[1].user_project.build_configurations[0].build_settings["CLANG_CXX_LANGUAGE_STANDARD"], "c++17")
+        assert_equal(installer.pods_project.targets[1].received_resolved_build_setting_parameters, [ReceivedCommonResolvedBuildSettings.new("CLANG_CXX_LANGUAGE_STANDARD", true)])
+        assert_equal(Pod::UI.collected_messages, ["Setting CLANG_CXX_LANGUAGE_STANDARD to c++17 on /test/path.xcproj", "Setting CLANG_CXX_LANGUAGE_STANDARD to c++17 on /test/path2.xcproj"])
+    end
+end
+
+def prepare_mocked_installer_with_react_core
+    return InstallerMock.new(
+        PodsProjectMock.new([
+                TargetMock.new(
+                    "YogaKit",
+                    [
+                        BuildConfigurationMock.new("Debug"),
+                        BuildConfigurationMock.new("Release"),
+                    ]
+                ),
+                TargetMock.new(
+                    "React-Core",
+                    [
+                        BuildConfigurationMock.new("Debug", { "CLANG_CXX_LANGUAGE_STANDARD" => "c++17" }),
+                        BuildConfigurationMock.new("Release", { "CLANG_CXX_LANGUAGE_STANDARD" => "c++17" }),
+                    ]
+                )
+            ]
+        ),
+        [
+            AggregatedProjectMock.new(
+                UserProjectMock.new("/test/path.xcproj", [BuildConfigurationMock.new("Debug")])
+            ),
+            AggregatedProjectMock.new(
+                UserProjectMock.new("/test/path2.xcproj", [BuildConfigurationMock.new("Debug")])
+            ),
+        ]
+    )
+end
+
+def prepare_mocked_installer_with_react_core_and_different_language_standards
+    return InstallerMock.new(
+        PodsProjectMock.new([
+                TargetMock.new(
+                    "YogaKit",
+                    [
+                        BuildConfigurationMock.new("Debug"),
+                        BuildConfigurationMock.new("Release"),
+                    ]
+                ),
+                TargetMock.new(
+                    "React-Core",
+                    [
+                        BuildConfigurationMock.new("Debug", { "CLANG_CXX_LANGUAGE_STANDARD" => "c++17" }),
+                        BuildConfigurationMock.new("Release", { "CLANG_CXX_LANGUAGE_STANDARD" => "new" }),
+                    ]
+                )
+            ]
+        ),
+        [
+            AggregatedProjectMock.new(
+                UserProjectMock.new("/test/path.xcproj", [BuildConfigurationMock.new("Debug")])
+            ),
+            AggregatedProjectMock.new(
+                UserProjectMock.new("/test/path2.xcproj", [BuildConfigurationMock.new("Debug")])
+            ),
+        ]
+    )
+end
+
+def prepare_mocked_installer_without_react_core
+    return InstallerMock.new(
+        PodsProjectMock.new([
+                TargetMock.new(
+                    "YogaKit",
+                    [
+                        BuildConfigurationMock.new("Debug"),
+                        BuildConfigurationMock.new("Release"),
+                    ]
+                )
+            ]
+        ),
+        [
+            AggregatedProjectMock.new(
+                UserProjectMock.new("/test/path.xcproj", [BuildConfigurationMock.new("Debug")])
+            ),
+            AggregatedProjectMock.new(
+                UserProjectMock.new("/test/path2.xcproj", [BuildConfigurationMock.new("Debug")])
+            ),
+        ]
+    )
+end

scripts/cocoapods/__tests__/test_utils/InstallerMock.rb

@@ -38,9 +38,11 @@
 
 class InstallerMock
     attr_reader :pods_project
+    attr_reader :aggregate_targets
 
-    def initialize(pods_project = PodsProjectMock.new)
+    def initialize(pods_project = PodsProjectMock.new, aggregate_targets = [AggregatedProjectMock.new])
         @pods_project = pods_project
+        @aggregate_targets = aggregate_targets
     end
 
     def target_with_name(name)
@@ -58,13 +60,45 @@ def initialize(targets = [])
     end
 end
 
+class AggregatedProjectMock
+    attr_reader :user_project
+
+    def initialize(user_project = UserProjectMock.new)
+        @user_project = user_project
+    end
+end
+
+class UserProjectMock
+    attr_reader :path
+    attr_reader :build_configurations
+
+    def initialize(path = "/test/path.xcproj", build_configurations = [])
+        @path = path
+        @build_configurations = build_configurations
+    end
+
+    def save()
+    end
+end
+
+ReceivedCommonResolvedBuildSettings = Struct.new(:key, :resolve_against_xcconfig)
+
 class TargetMock
     attr_reader :name
     attr_reader :build_configurations
 
+    attr_reader :received_resolved_build_setting_parameters
+
     def initialize(name, build_configurations = [])
         @name = name
         @build_configurations = build_configurations
+        @received_resolved_build_setting_parameters = []
+    end
+
+    def resolved_build_setting(key, resolve_against_xcconfig: false)
+        received_resolved_build_setting_parameters.append(ReceivedCommonResolvedBuildSettings.new(key, resolve_against_xcconfig))
+
+        return {name: build_configurations[0].build_settings[key]}
     end
 end
 

scripts/cocoapods/new_architecture.rb

@@ -0,0 +1,30 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+def set_clang_cxx_language_standard_if_needed(installer)
+    language_standard = nil
+
+    installer.pods_project.targets.each do |target|
+        if target.name == 'React-Core'
+            language_standard = target.resolved_build_setting("CLANG_CXX_LANGUAGE_STANDARD", resolve_against_xcconfig: true).values[0]
+        end
+    end
+
+    unless language_standard.nil?
+        projects = installer.aggregate_targets
+            .map{ |t| t.user_project }
+            .uniq{ |p| p.path }
+
+        projects.each do |project|
+            Pod::UI.puts("Setting CLANG_CXX_LANGUAGE_STANDARD to #{ language_standard } on #{ project.path }")
+
+            project.build_configurations.each do |config|
+                config.build_settings["CLANG_CXX_LANGUAGE_STANDARD"] = language_standard
+            end
+
+            project.save()
+        end
+    end
+end