add check that xcode project configuration is not missing (#31621)

packages/flutter_tools/lib/src/application_package.dart

@@ -319,7 +319,7 @@ abstract class IOSApp extends ApplicationPackage {
       return null;
     }
     if (!project.exists) {
-      // If the project doesn't exist at all the existing hint to run flutter
+      // If the project doesn't exist at all the current hint to run flutter
       // create is accurate.
       return null;
     }
@@ -327,6 +327,10 @@ abstract class IOSApp extends ApplicationPackage {
       printError('Expected ios/Runner.xcodeproj but this file is missing.');
       return null;
     }
+    if (!project.xcodeProjectInfoFile.existsSync()) {
+      printError('Expected ios/Runner.xcodeproj/project.pbxproj but this file is missing.');
+      return null;
+    }
     return BuildableIOSApp(project);
   }
 

packages/flutter_tools/test/application_package_test.dart

@@ -294,6 +294,15 @@ void main() {
 
       expect(iosApp, null);
     }, overrides: overrides);
+
+    testUsingContext('returns null when there is no Runner.xcodeproj/project.pbxproj', () async {
+      fs.file('pubspec.yaml').createSync();
+      fs.file('.packages').createSync();
+      fs.file('ios/Runner.xcodeproj').createSync(recursive: true);
+      final BuildableIOSApp iosApp = IOSApp.fromIosProject((await FlutterProject.fromDirectory(fs.currentDirectory)).ios);
+
+      expect(iosApp, null);
+    }, overrides: overrides);
   });
 }