Let spm deinit take an app back to CocoaPods

.github/workflows/test-ios-spm-helloworld.yml

@@ -94,11 +94,11 @@ jobs:
             echo "::error::spm add did not inject SwiftPM: $XCODE_PROJECT/.spm-injected.json is missing"
             exit 1
           fi
-          if [[ -f Podfile ]] && grep -q 'use_react_native!' Podfile; then
-            echo "::error::spm add --deintegrate left use_react_native! in the Podfile"
+          if grep -q 'Pods-' "$XCODE_PROJECT/project.pbxproj"; then
+            echo "::error::spm add --deintegrate left CocoaPods references in $XCODE_PROJECT"
             exit 1
           fi
-          echo "SwiftPM injected in place; Podfile de-integrated."
+          echo "SwiftPM injected in place; CocoaPods de-integrated."
       - name: Build ${{ env.XCODE_SCHEME }} (${{ matrix.flavor }})
         shell: bash
         working-directory: ${{ env.APP_IOS_DIR }}

.github/workflows/test-ios-spm-newapp.yml

@@ -105,11 +105,11 @@ jobs:
             echo "::error::spm add did not inject SwiftPM: $XCODE_PROJECT/.spm-injected.json is missing"
             exit 1
           fi
-          if [[ -f Podfile ]] && grep -q 'use_react_native!' Podfile; then
-            echo "::error::spm add --deintegrate left use_react_native! in the Podfile"
+          if grep -q 'Pods-' "$XCODE_PROJECT/project.pbxproj"; then
+            echo "::error::spm add --deintegrate left CocoaPods references in $XCODE_PROJECT"
             exit 1
           fi
-          echo "SwiftPM injected in place; Podfile de-integrated."
+          echo "SwiftPM injected in place; CocoaPods de-integrated."
       - name: Build ${{ env.XCODE_SCHEME }} (${{ matrix.flavor }})
         shell: bash
         working-directory: ${{ env.APP_IOS_DIR }}

.github/workflows/test-ios-spm-rntester.yml

@@ -94,11 +94,11 @@ jobs:
             echo "::error::spm add did not inject SwiftPM: $XCODE_PROJECT/.spm-injected.json is missing"
             exit 1
           fi
-          if [[ -f Podfile ]] && grep -q 'use_react_native!' Podfile; then
-            echo "::error::spm add --deintegrate left use_react_native! in the Podfile"
+          if grep -q 'Pods-' "$XCODE_PROJECT/project.pbxproj"; then
+            echo "::error::spm add --deintegrate left CocoaPods references in $XCODE_PROJECT"
             exit 1
           fi
-          echo "SwiftPM injected in place; Podfile de-integrated."
+          echo "SwiftPM injected in place; CocoaPods de-integrated."
       - name: Build ${{ env.XCODE_SCHEME }} (${{ matrix.flavor }})
         shell: bash
         working-directory: ${{ env.APP_IOS_DIR }}

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

@@ -208,5 +208,6 @@ def link_native_modules!(config)
 # - config_command: the command to run to get the application's current config, e.g. ['npx', '@react-native-community/cli', 'config'],
 #                   you can override this if you'd like to avoid the dependency. e.g. ['cat', 'your_config.json']
 def use_native_modules!(config_command = $default_command)
+  ReactNativePodsUtils.error_if_spm_injected
   return link_native_modules!(list_native_modules!(config_command))
 end

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

@@ -316,6 +316,24 @@ def self.create_xcode_env_if_missing(file_manager: File)
         end
     end
 
+    # Stops `pod install` on an app that `npx react-native spm add` converted to
+    # Swift Package Manager. Codegen would rewrite the app's generated
+    # Package.swift, and Xcode resolves packages before any build phase can
+    # report it, so this has to run before React Native writes any file.
+    # prepare_react_native_project!, use_native_modules! and use_react_native!
+    # all call it, because a Podfile need not call the first.
+    def self.error_if_spm_injected
+        podfile_dir = Pod::Config.instance.installation_root.to_s
+        xcodeproj = Dir.glob('*.xcodeproj', base: podfile_dir).sort.find do |name|
+            File.exist?(File.join(podfile_dir, name, '.spm-injected.json'))
+        end
+        return if xcodeproj.nil?
+
+        raise Pod::Informative, "This app uses Swift Package Manager for React Native " +
+            "(#{xcodeproj} has .spm-injected.json), so `pod install` would break the Xcode project. " +
+            "To go back to CocoaPods, run `npx react-native spm deinit` first, then `pod install`."
+    end
+
     # It examines the target_definition property and sets the appropriate value for
     # ENV['USE_FRAMEWORKS'] variable.
     #

packages/react-native/scripts/react_native_pods.rb

@@ -47,6 +47,8 @@ def min_supported_versions
 # This function prepares the project for React Native, before processing
 # all the target exposed by the framework.
 def prepare_react_native_project!
+  ReactNativePodsUtils.error_if_spm_injected
+
   # Temporary solution to suppress duplicated GUID error & master specs repo warning.
   # Can be removed once we move to generate files outside pod install.
   install! 'cocoapods', :deterministic_uuids => false, :warn_for_unused_master_specs_repo => false
@@ -96,6 +98,7 @@ def use_react_native! (
   config_file_dir: '',
   privacy_file_aggregation_enabled: true
 )
+  ReactNativePodsUtils.error_if_spm_injected
   error_if_try_to_use_jsc_from_core()
   warn_if_new_arch_disabled()