prohibit scheduling startup activities in default project

they won't be run anyway

platform/lang-impl/src/com/intellij/openapi/roots/impl/ProjectRootManagerComponent.java

@@ -91,7 +91,9 @@ public class ProjectRootManagerComponent extends ProjectRootManagerImpl implemen
       }
     }, project);
 
-    startupManager.registerStartupActivity(() -> myStartupActivityPerformed = true);
+    if (!myProject.isDefault()) {
+      startupManager.registerStartupActivity(() -> myStartupActivityPerformed = true);
+    }
 
     myHandler = new BatchUpdateListener() {
       @Override

platform/platform-impl/src/com/intellij/ide/startup/impl/StartupManagerImpl.java

@@ -77,20 +77,27 @@ public class StartupManagerImpl extends StartupManagerEx {
     myProject = project;
   }
 
+  private void checkNonDefaultProject() {
+    LOG.assertTrue(!myProject.isDefault(), "Please don't register startup activities for the default project: they won't ever be run");
+  }
+
   @Override
   public void registerPreStartupActivity(@NotNull Runnable runnable) {
+    checkNonDefaultProject();
     LOG.assertTrue(!myPreStartupActivitiesPassed, "Registering pre startup activity that will never be run");
     myPreStartupActivities.add(runnable);
   }
 
   @Override
   public void registerStartupActivity(@NotNull Runnable runnable) {
+    checkNonDefaultProject();
     LOG.assertTrue(!myStartupActivitiesPassed, "Registering startup activity that will never be run");
     myStartupActivities.add(runnable);
   }
 
   @Override
   public synchronized void registerPostStartupActivity(@NotNull Runnable runnable) {
+    checkNonDefaultProject();
     LOG.assertTrue(!myPostStartupActivitiesPassed, "Registering post-startup activity that will never be run:" +
                                                    " disposed=" + myProject.isDisposed() + "; open=" + myProject.isOpen() + "; passed=" + myStartupActivitiesPassed);
     (DumbService.isDumbAware(runnable) ? myDumbAwarePostStartupActivities : myNotDumbAwarePostStartupActivities).add(runnable);
@@ -372,7 +379,7 @@ public class StartupManagerImpl extends StartupManagerEx {
     synchronized (this) {
       // in tests which simulate project opening, post-startup activities could have been run already.
       // Then we should act as if the project was initialized
-      boolean initialized = myProject.isInitialized() || application.isUnitTestMode() && myPostStartupActivitiesPassed;
+      boolean initialized = myProject.isInitialized() || myProject.isDefault() || application.isUnitTestMode() && myPostStartupActivitiesPassed;
       if (!initialized) {
         registerPostStartupActivity(action);
         return;

platform/platform-impl/src/com/intellij/openapi/vcs/impl/FileStatusManagerImpl.java

@@ -106,6 +106,8 @@ public class FileStatusManagerImpl extends FileStatusManager implements ProjectC
       }
     });
 
+    if (project.isDefault()) return;
+
     startupManager.registerPreStartupActivity(() -> {
       DocumentAdapter documentListener = new DocumentAdapter() {
         @Override
@@ -123,12 +125,7 @@ public class FileStatusManagerImpl extends FileStatusManager implements ProjectC
         factory.getEventMulticaster().addDocumentListener(documentListener, myProject);
       }
     });
-    startupManager.registerPostStartupActivity(new DumbAwareRunnable() {
-      @Override
-      public void run() {
-        fileStatusesChanged();
-      }
-    });
+    startupManager.registerPostStartupActivity((DumbAwareRunnable)() -> fileStatusesChanged());
   }
 
   public void setFileStatusProvider(final FileStatusProvider fileStatusProvider) {

platform/vcs-impl/src/com/intellij/openapi/vcs/impl/VcsInitialization.java

@@ -43,7 +43,7 @@ public class VcsInitialization implements Disposable {
   private static final Logger LOG = Logger.getInstance("#com.intellij.openapi.vcs.impl.VcsInitialization");
 
   private final List<Pair<VcsInitObject, Runnable>> myList = new ArrayList<>();
-  private final Object myLock;
+  private final Object myLock = new Object();
   @NotNull private final Project myProject;
 
   // the initialization lifecycle: IDLE -(on startup completion)-> RUNNING -(on all tasks executed or project canceled)-> FINISHED
@@ -55,7 +55,7 @@ public class VcsInitialization implements Disposable {
 
   VcsInitialization(@NotNull final Project project) {
     myProject = project;
-    myLock = new Object();
+    if (project.isDefault()) return;
 
     StartupManager.getInstance(project).registerPostStartupActivity((DumbAwareRunnable)() -> {
       if (project.isDisposed()) return;