Fix Android Studio 2025.2 project open hang by using StartupActivity (projects with missing .idea directories)

The custom `FlutterStudioProjectOpenProcessor` was causing hangs and crashes due to threading issues when delegating to the Platform's project opener in newer Android Studio versions.
This change:
- Removes `FlutterStudioProjectOpenProcessor` entirely, allowing the robust standard Platform processor to handle project opening.
- Moves the necessary Flutter configuration (setting module type, enabling Dart SDK) to FlutterStudioStartupActivity, ensuring it runs safely after startup.

Fixes #8661

Author: jwren

CHANGELOG.md

@@ -9,6 +9,7 @@
 ### Fixed
 
 - DtdUtils static field retaining disposed Project (#8658)
+- Fixed project open hang in Android Studio 2025.2 by removing legacy `FlutterStudioProjectOpenProcessor` and migrating configuration logic to `FlutterStudioStartupActivity`. (#8661)
 
 ## 88.2.0
 

resources/META-INF/studio-contribs.xml

@@ -9,7 +9,6 @@
   <extensions defaultExtensionNs="com.intellij">
     <externalSystemTaskNotificationListener implementation="io.flutter.utils.FlutterExternalSystemTaskNotificationListener"/>
     <postStartupActivity implementation="io.flutter.FlutterStudioStartupActivity"/>
-    <projectOpenProcessor implementation="io.flutter.editor.FlutterStudioProjectOpenProcessor" order="after flutter"/>
     <library.type implementation="io.flutter.android.AndroidModuleLibraryType"/>
     <projectService serviceImplementation="io.flutter.android.AndroidModuleLibraryManager"/>
 

src/io/flutter/FlutterStudioStartupActivity.java

@@ -7,6 +7,7 @@
 
 import com.intellij.ide.projectView.ProjectView;
 import com.intellij.ide.util.PropertiesComponent;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.application.ReadAction;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.project.Project;
@@ -22,6 +23,8 @@
 import io.flutter.utils.OpenApiUtils;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Objects;
+
 public class FlutterStudioStartupActivity extends FlutterProjectActivity {
   private static @NotNull Logger LOG = PluginLogger.createLogger(FlutterStudioStartupActivity.class);
   private static final String IS_FIRST_OPEN_KEY = "io.flutter.project.isFirstOpen";
@@ -58,6 +61,21 @@ public void executeProjectStartup(@NotNull Project project) {
       return;
     }
 
+    // Ensure Flutter project configuration is applied.
+    // This logic was previously in FlutterStudioProjectOpenProcessor. However, that processor
+    // caused hangs and crashes due to threading issues when delegating to the Platform processor (AS 2025.2).
+    // Instead, we let the Platform open the project normally, and then apply our configuration here.
+    // This includes ensuring the module type is set to 'flutter' (for icons/facets) and enabling the Dart SDK.
+    // See https://github.com/flutter/flutter-intellij/issues/8661
+    for (com.intellij.openapi.module.Module module : FlutterModuleUtils.getModules(project)) {
+      if (FlutterModuleUtils.declaresFlutter(module) && !FlutterModuleUtils.isFlutterModule(module)) {
+        Objects.requireNonNull(ApplicationManager.getApplication()).runWriteAction(() -> {
+          FlutterModuleUtils.setFlutterModuleType(module);
+        });
+        FlutterModuleUtils.enableDartSDK(module);
+      }
+    }
+
     // Set project tool window to show the project on first open (Android Studio sometimes opens android view instead).
     // See https://github.com/flutter/flutter-intellij/issues/8556.
     // Note: After showing the project view, subsequent opens should go to the project view also. However, if the android subdirectory is