Avoid duplicating Pods-Runner xcconfig #includes (#75822)

packages/flutter_tools/lib/src/macos/cocoapods.dart

@@ -274,9 +274,10 @@ class CocoaPods {
     final File file = xcodeProject.xcodeConfigFor(mode);
     if (file.existsSync()) {
       final String content = file.readAsStringSync();
-      final String include = '#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.${mode
-          .toLowerCase()}.xcconfig"';
-      if (!content.contains(include)) {
+      final String includeFile = 'Pods/Target Support Files/Pods-Runner/Pods-Runner.${mode
+          .toLowerCase()}.xcconfig';
+      final String include = '#include? "$includeFile"';
+      if (!content.contains(includeFile)) {
         file.writeAsStringSync('$include\n$content', flush: true);
       }
     }

packages/flutter_tools/test/general.shard/macos/cocoapods_test.dart

@@ -260,6 +260,34 @@ void main() {
       FileSystem: () => fileSystem,
       ProcessManager: () => FakeProcessManager.any(),
     });
+
+    testUsingContext('does not include Pod config in xcconfig files, if legacy non-option include present', () async {
+      projectUnderTest.ios.podfile..createSync()..writeAsStringSync('Existing Podfile');
+
+      const String legacyDebugInclude = '#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig';
+      projectUnderTest.ios.xcodeConfigFor('Debug')
+        ..createSync(recursive: true)
+        ..writeAsStringSync(legacyDebugInclude);
+      const String legacyReleaseInclude = '#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig';
+      projectUnderTest.ios.xcodeConfigFor('Release')
+        ..createSync(recursive: true)
+        ..writeAsStringSync(legacyReleaseInclude);
+
+      final FlutterProject project = FlutterProject.fromPath('project');
+      await cocoaPodsUnderTest.setupPodfile(project.ios);
+
+      final String debugContents = projectUnderTest.ios.xcodeConfigFor('Debug').readAsStringSync();
+      // Redundant contains check, but this documents what we're testing--that the optional
+      // #include? doesn't get written in addition to the previous style #include.
+      expect(debugContents, isNot(contains('#include?')));
+      expect(debugContents, equals(legacyDebugInclude));
+      final String releaseContents = projectUnderTest.ios.xcodeConfigFor('Release').readAsStringSync();
+      expect(releaseContents, isNot(contains('#include?')));
+      expect(releaseContents, equals(legacyReleaseInclude));
+    }, overrides: <Type, Generator>{
+      FileSystem: () => fileSystem,
+      ProcessManager: () => FakeProcessManager.any(),
+    });
   });
 
   group('Update xcconfig', () {