[CQ] fix nullability problems for flutter/actions (#8293)

Fix nullability problems for all the actions in
`src/io/flutter/actions/`.

See #8291.

If we pursue #8292, we
could mark `src/io/flutter/actions/` as null-"clean".

---

- [x] I’ve reviewed the contributor guide and applied the relevant
portions to this PR.

<details>
  <summary>Contribution guidelines:</summary><br>

- See our [contributor
guide]([https://github.com/dart-lang/sdk/blob/main/CONTRIBUTING.md](https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview)
for general expectations for PRs.
- Larger or significant changes should be discussed in an issue before
creating a PR.
- Dart contributions to our repos should follow the [Dart style
guide](https://dart.dev/guides/language/effective-dart) and use `dart
format`.
- Java and Kotlin contributions should strive to follow Java and Kotlin
best practices
([discussion](#8098)).
</details>

Author: pq

flutter-idea/src/io/flutter/actions/AttachDebuggerAction.java

@@ -125,7 +125,7 @@ public boolean enableActionInBazelContext() {
   }
 
   @Override
-  public void update(AnActionEvent e) {
+  public void update(@NotNull AnActionEvent e) {
     final Project project = e.getProject();
     if (project == null || project.isDefault()) {
       super.update(e);
@@ -159,7 +159,7 @@ public void update(AnActionEvent e) {
   }
 
   @Nullable
-  public static RunConfiguration findRunConfig(Project project) {
+  public static RunConfiguration findRunConfig(@NotNull Project project) {
     // Look for a Flutter run config. If exactly one is found then return it otherwise return null.
     final RunManagerEx mgr = RunManagerEx.getInstanceEx(project);
     final List<RunConfiguration> configs = mgr.getAllConfigurationsList();
@@ -174,7 +174,7 @@ public static RunConfiguration findRunConfig(Project project) {
     return count == 1 ? sdkConfig : null;
   }
 
-  private static void onAttachTermination(@NotNull Project project, @NotNull Consumer<Project> runner) {
+  private static void onAttachTermination(@NotNull Project project, @NotNull Consumer<@NotNull Project> runner) {
     final MessageBusConnection connection = project.getMessageBus().connect();
 
     // Need an ExecutionListener to clean up project-scoped state when the Stop button is clicked.
@@ -221,7 +221,9 @@ private static class SelectConfigDialog extends DialogWrapper {
                                   "module was created. See <a href=\"" +
                                   FlutterConstants.URL_RUN_AND_DEBUG +
                                   "\">the Flutter documentation</a> for more information.</body></html>";
+      //noinspection DataFlowIssue
       myTextPane.setText(selectConfig);
+      //noinspection DataFlowIssue
       myPanel.add(myTextPane);
       init();
       //noinspection ConstantConditions

flutter-idea/src/io/flutter/actions/DeviceSelectorAction.java

@@ -35,7 +35,7 @@ public class DeviceSelectorAction extends ComboBoxAction implements DumbAware {
   private final List<AnAction> actions = new ArrayList<>();
   private final List<Project> knownProjects = Collections.synchronizedList(new ArrayList<>());
 
-  private SelectDeviceAction selectedDeviceAction;
+  private @Nullable SelectDeviceAction selectedDeviceAction;
 
   DeviceSelectorAction() {
     setSmallVariant(true);
@@ -73,24 +73,29 @@ public void update(@NotNull AnActionEvent e) {
     if (!knownProjects.contains(project)) {
       knownProjects.add(project);
       final Application application = ApplicationManager.getApplication();
-      application.getMessageBus().connect().subscribe(ProjectManager.TOPIC, new ProjectManagerListener() {
-        @Override
-        public void projectClosed(@NotNull Project closedProject) {
-          knownProjects.remove(closedProject);
-        }
-      });
+      if (application != null) {
+        application.getMessageBus().connect().subscribe(ProjectManager.TOPIC, new ProjectManagerListener() {
+          @Override
+          public void projectClosed(@NotNull Project closedProject) {
+            knownProjects.remove(closedProject);
+          }
+        });
+      }
       Runnable deviceListener = () -> queueUpdate(project, e.getPresentation());
       DeviceService.getInstance(project).addListener(deviceListener);
 
       // Listen for android device changes, and rebuild the menu if necessary.
       Runnable emulatorListener = () -> queueUpdate(project, e.getPresentation());
       AndroidEmulatorManager.getInstance(project).addListener(emulatorListener);
-      ProjectManager.getInstance().addProjectManagerListener(project, new ProjectManagerListener() {
-        public void projectClosing(@NotNull Project project) {
-          DeviceService.getInstance(project).removeListener(deviceListener);
-          AndroidEmulatorManager.getInstance(project).removeListener(emulatorListener);
-        }
-      });
+      var projectManager = ProjectManager.getInstance();
+      if (projectManager != null) {
+        projectManager.addProjectManagerListener(project, new ProjectManagerListener() {
+          public void projectClosing(@NotNull Project project) {
+            DeviceService.getInstance(project).removeListener(deviceListener);
+            AndroidEmulatorManager.getInstance(project).removeListener(emulatorListener);
+          }
+        });
+      }
       update(project, presentation);
     }
 
@@ -139,9 +144,10 @@ private static void updateVisibility(final Project project, final @NotNull Prese
     final JComponent component = presentation.getClientProperty(new Key<>("customComponent"));
     if (component != null) {
       component.setVisible(visible);
-      if (component.getParent() != null) {
-        component.getParent().doLayout();
-        component.getParent().repaint();
+      var parent = component.getParent();
+      if (parent != null) {
+        parent.doLayout();
+        parent.repaint();
       }
     }
   }
@@ -165,13 +171,16 @@ private void updateActions(@NotNull Project project, Presentation presentation)
     selectedDeviceAction = null;
 
     for (FlutterDevice device : devices) {
+      if (device == null) continue;
+
       final SelectDeviceAction deviceAction = new SelectDeviceAction(device, devices);
       actions.add(deviceAction);
 
       if (Objects.equals(device, selectedDevice)) {
         selectedDeviceAction = deviceAction;
 
         final Presentation template = deviceAction.getTemplatePresentation();
+        //noinspection DataFlowIssue
         presentation.setIcon(template.getIcon());
         //presentation.setText(deviceAction.presentationName());
         presentation.setEnabled(true);
@@ -196,15 +205,19 @@ private void updateActions(@NotNull Project project, Presentation presentation)
 
     // Add Open Android emulators actions.
     final List<OpenEmulatorAction> emulatorActions = OpenEmulatorAction.getEmulatorActions(project);
-    if (!emulatorActions.isEmpty()) {
+    if (emulatorActions != null && !emulatorActions.isEmpty()) {
       actions.add(new Separator());
       actions.addAll(emulatorActions);
     }
     if (!FlutterModuleUtils.hasInternalDartSdkPath(project)) {
       actions.add(new Separator());
       actions.add(RestartFlutterDaemonAction.forDeviceSelector());
     }
-    ActivityTracker.getInstance().inc();
+
+    var tracker = ActivityTracker.getInstance();
+    if (tracker != null) {
+      tracker.inc();
+    }
   }
 
   // Show the current device as selected when the combo box menu opens.
@@ -222,12 +235,12 @@ private static class SelectDeviceAction extends AnAction {
       this.device = device;
     }
 
-    public String presentationName() {
+    public @NotNull String presentationName() {
       return device.presentationName();
     }
 
     @Override
-    public void actionPerformed(AnActionEvent e) {
+    public void actionPerformed(@NotNull AnActionEvent e) {
       final Project project = e.getProject();
       final DeviceService service = project == null ? null : DeviceService.getInstance(project);
       if (service != null) {

flutter-idea/src/io/flutter/actions/ExtractWidgetAction.java

@@ -31,11 +31,15 @@
 
 public class ExtractWidgetAction extends DumbAwareAction {
   @Override
-  public void actionPerformed(AnActionEvent event) {
+  public void actionPerformed(@NotNull AnActionEvent event) {
     final DataContext dataContext = event.getDataContext();
+    //noinspection DataFlowIssue
     final Project project = dataContext.getData(PlatformDataKeys.PROJECT);
+    //noinspection DataFlowIssue
     final VirtualFile file = dataContext.getData(PlatformDataKeys.VIRTUAL_FILE);
+    //noinspection DataFlowIssue
     final Editor editor = dataContext.getData(PlatformDataKeys.EDITOR);
+    //noinspection DataFlowIssue
     final Caret caret = dataContext.getData(PlatformDataKeys.CARET);
 
     if (project != null && file != null && editor != null && caret != null) {
@@ -51,7 +55,9 @@ public void actionPerformed(AnActionEvent event) {
       if (initialStatus.hasError()) {
         final String message = initialStatus.getMessage();
         assert message != null;
-        CommonRefactoringUtil.showErrorHint(project, editor, message, CommonBundle.getErrorTitle(), null);
+        String title = CommonBundle.getErrorTitle();
+        assert title != null;
+        CommonRefactoringUtil.showErrorHint(project, editor, message, title, null);
         return;
       }
 
@@ -60,7 +66,7 @@ public void actionPerformed(AnActionEvent event) {
   }
 
   @Override
-  public void update(AnActionEvent e) {
+  public void update(@NotNull AnActionEvent e) {
     e.getPresentation().setVisible(isVisibleFor(e));
     super.update(e);
   }
@@ -70,17 +76,17 @@ public void update(AnActionEvent e) {
     return ActionUpdateThread.BGT;
   }
 
-  protected static boolean isVisibleFor(AnActionEvent e) {
+  protected static boolean isVisibleFor(@NotNull AnActionEvent e) {
     final DataContext dataContext = e.getDataContext();
-    final Project project = dataContext.getData(PlatformDataKeys.PROJECT);
+    //noinspection DataFlowIssue
     final VirtualFile file = dataContext.getData(PlatformDataKeys.VIRTUAL_FILE);
     return file != null && FlutterUtils.isDartFile(file);
   }
 }
 
 class ExtractWidgetDialog extends ServerRefactoringDialog<ExtractWidgetRefactoring> {
-  @NotNull final ExtractWidgetRefactoring myRefactoring;
-  private final JTextField myNameField = new JTextField();
+  final @NotNull ExtractWidgetRefactoring myRefactoring;
+  private final @NotNull JTextField myNameField = new JTextField();
 
   public ExtractWidgetDialog(@NotNull Project project,
                              @Nullable Editor editor,
@@ -92,17 +98,21 @@ public ExtractWidgetDialog(@NotNull Project project,
 
     myNameField.setText("NewWidget");
     myNameField.selectAll();
-    myNameField.getDocument().addDocumentListener(new DocumentAdapter() {
-      @Override
-      protected void textChanged(@NotNull DocumentEvent event) {
-        updateRefactoringOptions();
-      }
-    });
+    var document = myNameField.getDocument();
+    if (document != null) {
+      document.addDocumentListener(new DocumentAdapter() {
+        @Override
+        protected void textChanged(@NotNull DocumentEvent event) {
+          updateRefactoringOptions();
+        }
+      });
+    }
 
     updateRefactoringOptions();
   }
 
   private void updateRefactoringOptions() {
+    //noinspection DataFlowIssue
     myRefactoring.setName(myNameField.getText());
     myRefactoring.sendOptions();
   }
@@ -137,6 +147,7 @@ protected JComponent createNorthPanel() {
     gbConstraints.fill = GridBagConstraints.BOTH;
     gbConstraints.anchor = GridBagConstraints.WEST;
     panel.add(myNameField, gbConstraints);
+    //noinspection DataFlowIssue
     myNameField.setPreferredSize(new Dimension(200, myNameField.getPreferredSize().height));
 
     return panel;

flutter-idea/src/io/flutter/actions/FlutterBuildActionGroup.java

@@ -24,15 +24,13 @@
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.List;
-
 public class FlutterBuildActionGroup extends DefaultActionGroup {
 
   public static void build(@NotNull Project project,
-                                       @NotNull PubRoot pubRoot,
-                                       @NotNull FlutterSdk sdk,
-                                       @NotNull BuildType buildType,
-                                       @Nullable String desc) {
+                           @NotNull PubRoot pubRoot,
+                           @NotNull FlutterSdk sdk,
+                           @NotNull BuildType buildType,
+                           @Nullable String desc) {
     final ProgressHelper progressHelper = new ProgressHelper(project);
     progressHelper.start(desc == null ? "building" : desc);
     ProcessAdapter processAdapter = new ProcessAdapter() {
@@ -105,7 +103,12 @@ public static Module findFlutterModule(@NotNull Project project, @NotNull Virtua
       return module;
     }
     // We may get here if the file is in the Android module of a Flutter module project.
-    final VirtualFile parent = OpenApiUtils.getContentRoots(module)[0].getParent();
+    var root = OpenApiUtils.getContentRoots(module)[0];
+    if (root == null) return null;
+
+    final VirtualFile parent = root.getParent();
+    if (parent == null) return null;
+
     module = ModuleUtilCore.findModuleForFile(parent, project);
     if (module == null) {
       return null;
@@ -135,7 +138,7 @@ public void actionPerformed(@NotNull AnActionEvent event) {
         build(project, pubRoot, sdk, buildType, presentation.getDescription());
       }
       else {
-        List<PubRoot> roots = PubRoots.forProject(project);
+        var roots = PubRoots.forProject(project);
         for (PubRoot sub : roots) {
           build(project, sub, sdk, buildType, presentation.getDescription());
         }

flutter-idea/src/io/flutter/actions/FlutterExternalIdeActionGroup.java

@@ -18,8 +18,8 @@
  * See https://github.com/flutter/flutter-intellij/issues/7103
  */
 public class FlutterExternalIdeActionGroup extends DefaultActionGroup {
-  private static boolean isExternalIdeFile(AnActionEvent e) {
-    final VirtualFile file = e.getData(CommonDataKeys.VIRTUAL_FILE);
+  private static boolean isExternalIdeFile(@NotNull AnActionEvent e) {
+    @SuppressWarnings("DataFlowIssue") final VirtualFile file = e.getData(CommonDataKeys.VIRTUAL_FILE);
     if (file == null || !file.exists()) {
       return false;
     }
@@ -86,7 +86,7 @@ private static boolean isProjectDirectory(@NotNull VirtualFile file, @Nullable P
   }
 
   @Override
-  public void update(AnActionEvent event) {
+  public void update(@NotNull AnActionEvent event) {
     final Presentation presentation = event.getPresentation();
     final boolean enabled = isExternalIdeFile(event);
     presentation.setEnabled(enabled);

flutter-idea/src/io/flutter/actions/FlutterPackagesExplorerActionGroup.java

@@ -14,7 +14,7 @@
 public class FlutterPackagesExplorerActionGroup extends DefaultActionGroup {
 
   private static boolean isFlutterPubspec(@NotNull AnActionEvent e) {
-    final VirtualFile file = CommonDataKeys.VIRTUAL_FILE.getData(e.getDataContext());
+    @SuppressWarnings("DataFlowIssue") final VirtualFile file = CommonDataKeys.VIRTUAL_FILE.getData(e.getDataContext());
     final PubRoot root = file == null ? null : PubRoot.forDirectory(file.getParent());
     return root != null && root.getPubspec().equals(file) && root.declaresFlutter();
   }

flutter-idea/src/io/flutter/actions/FlutterRetargetAppAction.java

@@ -33,7 +33,7 @@ public abstract class FlutterRetargetAppAction extends DumbAwareAction {
   FlutterRetargetAppAction(@NotNull String actionId,
                            @Nullable String text,
                            @Nullable String description,
-                           @SuppressWarnings("SameParameterValue") @NotNull String... places) {
+                           @SuppressWarnings("SameParameterValue") @NotNull String @NotNull ... places) {
     super(text, description, null);
     myActionId = actionId;
     myPlaces.addAll(Arrays.asList(places));
@@ -44,15 +44,15 @@ public abstract class FlutterRetargetAppAction extends DumbAwareAction {
   }
 
   @Override
-  public void actionPerformed(AnActionEvent e) {
+  public void actionPerformed(@NotNull AnActionEvent e) {
     final AnAction action = getAction(e.getProject());
     if (action != null) {
       action.actionPerformed(e);
     }
   }
 
   @Override
-  public void update(AnActionEvent e) {
+  public void update(@NotNull AnActionEvent e) {
     final Presentation presentation = e.getPresentation();
 
     final Project project = e.getProject();
@@ -76,7 +76,7 @@ public void update(AnActionEvent e) {
     }
   }
 
-  private AnAction getAction(@Nullable Project project) {
+  private @Nullable AnAction getAction(@Nullable Project project) {
     return project == null ? null : ProjectActions.getAction(project, myActionId);
   }
 }

flutter-idea/src/io/flutter/actions/FlutterSdkAction.java

@@ -82,7 +82,7 @@ public boolean enableActionInBazelContext() {
     return false;
   }
 
-  public static void showMissingSdkDialog(Project project) {
+  public static void showMissingSdkDialog(@Nullable Project project) {
     final int response = FlutterMessages.showDialog(project, FlutterBundle.message("flutter.sdk.notAvailable.message"),
                                                     FlutterBundle.message("flutter.sdk.notAvailable.title"),
                                                     new String[]{"Yes, configure", "No, thanks"}, -1);

flutter-idea/src/io/flutter/actions/OpenEmulatorAction.java

@@ -15,6 +15,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 import static java.util.stream.Collectors.toList;
 
@@ -33,12 +34,12 @@ public static List<OpenEmulatorAction> getEmulatorActions(Project project) {
     final AndroidEmulatorManager emulatorManager = AndroidEmulatorManager.getInstance(project);
 
     final List<AndroidEmulator> emulators = emulatorManager.getCachedEmulators();
-    return emulators.stream().map(OpenEmulatorAction::new).collect(toList());
+    return emulators.stream().filter(Objects::nonNull).map(OpenEmulatorAction::new).collect(toList());
   }
 
-  final AndroidEmulator emulator;
+  final @NotNull AndroidEmulator emulator;
 
-  public OpenEmulatorAction(AndroidEmulator emulator) {
+  public OpenEmulatorAction(@NotNull AndroidEmulator emulator) {
     super("Open Android Emulator: " + emulator.getName());
 
     this.emulator = emulator;