project structure: don't recreate modifiable models during applying changes (IDEA-168208)

Previously if someone tries to access ModuleRootModel after ModuleEditor.apply is called but before the model returned by it is committed (e.g. from myFacetsConfigurator.applyEditors) a new ModifiableRootModel instance will be created from the original ModuleRootModel, thus it won't include changes made in Project Structure dialog and may contain invalid OrderEntry instances.

java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/ModuleEditor.java

@@ -318,24 +318,21 @@ public abstract class ModuleEditor implements Place.Navigator, Disposable {
       myGenericSettingsPanel = null;
     }
     finally {
-      myModifiableRootModel = null;
-      myModifiableRootModelProxy = null;
+      resetModifiableModel();
     }
   }
 
   public ModifiableRootModel apply() throws ConfigurationException {
-    try {
-      for (ModuleConfigurationEditor editor : myEditors) {
-        editor.saveData();
-        editor.apply();
-      }
+    for (ModuleConfigurationEditor editor : myEditors) {
+      editor.saveData();
+      editor.apply();
+    }
+    return myModifiableRootModel;
+  }
 
-      return myModifiableRootModel;
-    }
-    finally {
-      myModifiableRootModel = null;
-      myModifiableRootModelProxy = null;
-    }
+  void resetModifiableModel() {
+    myModifiableRootModel = null;
+    myModifiableRootModelProxy = null;
   }
 
   public void canApply() throws ConfigurationException {

java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/ModulesConfigurator.java

@@ -313,6 +313,9 @@ public class ModulesConfigurator implements ModulesProvider, ModuleEditor.Change
 
       try {
         ModifiableModelCommitter.multiCommit(models, myModuleModel);
+        for (ModuleEditor editor : myModuleEditors.values()) {
+          editor.resetModifiableModel();
+        }
         myModuleModelCommitted = true;
         myFacetsConfigurator.commitFacets();