Fix NPE and lost chat requests while models are not loaded yet

com.microsoft.copilot.eclipse.core.test/src/com/microsoft/copilot/eclipse/core/lsp/CopilotLanguageServerConnectionTests.java

@@ -0,0 +1,51 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+package com.microsoft.copilot.eclipse.core.lsp;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+
+import org.eclipse.lsp4e.LanguageServerWrapper;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class CopilotLanguageServerConnectionTests {
+
+  @Mock
+  private LanguageServerWrapper languageServerWrapper;
+
+  private CopilotLanguageServerConnection connection;
+
+  @BeforeEach
+  void setUp() {
+    connection = new CopilotLanguageServerConnection(languageServerWrapper);
+  }
+
+  @Test
+  void testCreateConversation_noActiveModel_failsWithoutRequest() {
+    CompletableFuture<?> result = connection.createConversation("token", "hello", List.of(), null, null, null, null,
+        null, null, "Ask", null, null, null, null, null, null, null);
+
+    assertTrue(result.isCompletedExceptionally());
+    verify(languageServerWrapper, never()).execute(any());
+  }
+
+  @Test
+  void testAddConversationTurn_noActiveModel_failsWithoutRequest() {
+    CompletableFuture<?> result = connection.addConversationTurn("token", "conversation", "hello", List.of(), null,
+        null, null, null, null, "Ask", null, null, null, null, null);
+
+    assertTrue(result.isCompletedExceptionally());
+    verify(languageServerWrapper, never()).execute(any());
+  }
+}

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/CopilotLanguageServerConnection.java

@@ -273,6 +273,9 @@ public CompletableFuture<ChatCreateResult> createConversation(String workDoneTok
       String reasoningEffort, Integer contextSize, String chatModeName, String customChatModeId, List<TodoItem> todos,
       String agentSlug, String agentJobWorkspaceFolder, String conversationId, String restoreToTurnId,
       List<WorkspaceFolder> workspaceFolders) {
+    if (activeModel == null) {
+      return noActiveModelFailure();
+    }
 
     boolean supportVision = activeModel.getCapabilities().supports().vision();
     Either<String, List<ChatCompletionContentPart>> messageWithImages = ChatMessageUtils
@@ -331,6 +334,9 @@ public CompletableFuture<ChatTurnResult> addConversationTurn(String workDoneToke
       String reasoningEffort, Integer contextSize, String chatModeName, String customChatModeId,
       List<TodoItem> todoList, String agentSlug, String agentJobWorkspaceFolder,
       List<WorkspaceFolder> workspaceFolders) {
+    if (activeModel == null) {
+      return noActiveModelFailure();
+    }
 
     boolean supportVision = activeModel.getCapabilities().supports().vision();
     Either<String, List<ChatCompletionContentPart>> messageWithImages = ChatMessageUtils
@@ -732,6 +738,11 @@ public void stop() {
     this.languageServerWrapper.stop();
   }
 
+  private static <T> CompletableFuture<T> noActiveModelFailure() {
+    // The language server rejects chat requests without a model.
+    return CompletableFuture.failedFuture(new IllegalStateException("No active chat model available"));
+  }
+
   private String getModelName(CopilotModel activeModel) {
     return activeModel == null ? null
         : activeModel.isChatFallback() ? activeModel.getId() : activeModel.getModelFamily();

com.microsoft.copilot.eclipse.ui.test/src/com/microsoft/copilot/eclipse/ui/chat/ActionBarTest.java

@@ -0,0 +1,144 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+package com.microsoft.copilot.eclipse.ui.chat;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.mockito.Mockito.lenient;
+import static org.mockito.Mockito.mockStatic;
+
+import java.lang.reflect.Field;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.widgets.Button;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Shell;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.MockedStatic;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import com.microsoft.copilot.eclipse.core.CopilotCore;
+import com.microsoft.copilot.eclipse.core.FeatureFlags;
+import com.microsoft.copilot.eclipse.core.lsp.protocol.ChatMode;
+import com.microsoft.copilot.eclipse.ui.CopilotUi;
+import com.microsoft.copilot.eclipse.ui.chat.contextwindow.ContextWindowService;
+import com.microsoft.copilot.eclipse.ui.chat.services.AgentToolService;
+import com.microsoft.copilot.eclipse.ui.chat.services.ChatFontService;
+import com.microsoft.copilot.eclipse.ui.chat.services.ChatServiceManager;
+import com.microsoft.copilot.eclipse.ui.chat.services.McpConfigService;
+import com.microsoft.copilot.eclipse.ui.chat.services.ModelService;
+import com.microsoft.copilot.eclipse.ui.chat.services.ReferencedFileService;
+import com.microsoft.copilot.eclipse.ui.chat.services.UserPreferenceService;
+import com.microsoft.copilot.eclipse.ui.chat.tools.JavaDebuggerToolAdapter;
+import com.microsoft.copilot.eclipse.ui.utils.SwtUtils;
+
+@ExtendWith(MockitoExtension.class)
+class ActionBarTest {
+
+  @Mock
+  private UserPreferenceService mockUserPreferenceService;
+  @Mock
+  private ModelService mockModelService;
+  @Mock
+  private ChatServiceManager mockChatServiceManager;
+  @Mock
+  private ReferencedFileService mockReferencedFileService;
+  @Mock
+  private CopilotUi mockCopilotUi;
+  @Mock
+  private McpConfigService mockMcpConfigService;
+  @Mock
+  private AgentToolService mockAgentToolService;
+  @Mock
+  private ChatFontService mockChatFontService;
+  @Mock
+  private ContextWindowService mockContextWindowService;
+
+  private Shell shell;
+  private ActionBar actionBar;
+  private MockedStatic<CopilotUi> mockedCopilotUi;
+  private FeatureFlags featureFlags;
+  private boolean previewFeaturesEnabled;
+
+  @BeforeEach
+  void setUp() {
+    featureFlags = CopilotCore.getPlugin().getFeatureFlags();
+    previewFeaturesEnabled = featureFlags.isClientPreviewFeatureEnabled();
+    featureFlags.setClientPreviewFeatureEnabled(true);
+
+    mockedCopilotUi = mockStatic(CopilotUi.class);
+    mockedCopilotUi.when(CopilotUi::getPlugin).thenReturn(mockCopilotUi);
+    lenient().when(mockCopilotUi.getChatServiceManager()).thenReturn(mockChatServiceManager);
+    lenient().when(mockChatServiceManager.getUserPreferenceService()).thenReturn(mockUserPreferenceService);
+    lenient().when(mockChatServiceManager.getModelService()).thenReturn(mockModelService);
+    lenient().when(mockChatServiceManager.getReferencedFileService()).thenReturn(mockReferencedFileService);
+    lenient().when(mockChatServiceManager.getMcpConfigService()).thenReturn(mockMcpConfigService);
+    lenient().when(mockChatServiceManager.getAgentToolService()).thenReturn(mockAgentToolService);
+    lenient().when(mockChatServiceManager.getChatFontService()).thenReturn(mockChatFontService);
+    lenient().when(mockChatServiceManager.getContextWindowService()).thenReturn(mockContextWindowService);
+    lenient().when(mockAgentToolService.getTool(JavaDebuggerToolAdapter.TOOL_NAME)).thenReturn(null);
+    lenient().when(mockUserPreferenceService.getActiveChatMode()).thenReturn(ChatMode.Ask);
+
+    runOnDisplayThread(() -> {
+      shell = new Shell(Display.getDefault());
+      actionBar = new ActionBar(shell, SWT.NONE, mockChatServiceManager);
+    });
+  }
+
+  @AfterEach
+  void tearDown() {
+    SwtUtils.invokeOnDisplayThread(() -> {
+      if (shell != null && !shell.isDisposed()) {
+        shell.dispose();
+      }
+    });
+    mockedCopilotUi.close();
+    featureFlags.setClientPreviewFeatureEnabled(previewFeaturesEnabled);
+  }
+
+  @Test
+  void testUpdateButtonsLayout_noModelWithText_sendButtonsDisabled() {
+    AtomicReference<Boolean> sendEnabled = new AtomicReference<>();
+    AtomicReference<Boolean> delegateEnabled = new AtomicReference<>();
+    runOnDisplayThread(() -> {
+      actionBar.setInputTextViewerContent("hello");
+
+      // Recreates the send buttons, e.g. on chat mode switch
+      actionBar.updateButtonsLayout();
+      sendEnabled.set(getButton("btnMsgToggle").getEnabled());
+      delegateEnabled.set(getButton("sendToJobButton").getEnabled());
+    });
+
+    assertFalse(sendEnabled.get(), "Send must be disabled without a model");
+    assertFalse(delegateEnabled.get(), "Delegate must be disabled without a model");
+  }
+
+  // The workbench's syncExec swallows exceptions, so rethrow them on the test thread
+  private static void runOnDisplayThread(Runnable runnable) {
+    AtomicReference<Throwable> error = new AtomicReference<>();
+    SwtUtils.invokeOnDisplayThread(() -> {
+      try {
+        runnable.run();
+      } catch (Throwable t) {
+        error.set(t);
+      }
+    });
+    assertNull(error.get(), () -> "Unexpected error on display thread: " + error.get());
+  }
+
+  private Button getButton(String fieldName) {
+    try {
+      Field field = ActionBar.class.getDeclaredField(fieldName);
+      field.setAccessible(true);
+      return (Button) field.get(actionBar);
+    } catch (ReflectiveOperationException e) {
+      throw new IllegalStateException("Failed to read " + fieldName, e);
+    }
+  }
+}

com.microsoft.copilot.eclipse.ui.test/src/com/microsoft/copilot/eclipse/ui/chat/services/ModelServiceTests.java

@@ -9,6 +9,10 @@
 import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.timeout;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import java.io.IOException;
@@ -42,6 +46,7 @@
 import com.microsoft.copilot.eclipse.core.lsp.protocol.CopilotModel;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.CopilotScope;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.byok.ByokListModelResponse;
+import com.microsoft.copilot.eclipse.ui.chat.ActionBar;
 
 @ExtendWith(MockitoExtension.class)
 class ModelServiceTests {
@@ -231,6 +236,23 @@ void testSetActiveModel_AlreadyActiveModelDoesNotPersistPreference() throws Inte
     assertFalse(Files.exists(getPreferenceFile()));
   }
 
+  @Test
+  void testBindActionBarForModelAvailability_modelsPending_enablesSendOnlyAfterModelSet() {
+    CopilotModel defaultModel = createModel("gpt-4o", "GPT-4o", true);
+    CompletableFuture<CopilotModel[]> copilotModels = new CompletableFuture<>();
+    when(lsConnection.listModels()).thenReturn(copilotModels);
+    ActionBar actionBar = mock(ActionBar.class);
+
+    modelService = new ModelService(lsConnection, authStatusManager);
+    modelService.bindActionBarForModelAvailability(actionBar);
+
+    verify(actionBar, timeout(5000)).setModelAvailable(false);
+    verify(actionBar, never()).setModelAvailable(true);
+
+    copilotModels.complete(new CopilotModel[] { defaultModel });
+    verify(actionBar, timeout(5000)).setModelAvailable(true);
+  }
+
   private static CopilotModel createModel(String id, String name, boolean isChatDefault) {
     CopilotModel model = new CopilotModel();
     model.setId(id);

com.microsoft.copilot.eclipse.ui/src/com/microsoft/copilot/eclipse/ui/chat/ActionBar.java

@@ -98,6 +98,7 @@ public class ActionBar extends Composite implements NewConversationListener {
   private Image sendImage;
   private Image sendDisabledImage;
   private boolean isSendButton = true;
+  private boolean modelAvailable;
   private LinkedHashSet<MessageListener> messageListeners = new LinkedHashSet<>();
   private Button mcpToolButton;
   private Image mcpToolImage;
@@ -206,6 +207,7 @@ public ActionBar(Composite parent, int style, ChatServiceManager chatServiceMana
 
     ModelService modelService = chatServiceManager.getModelService();
     modelService.bindActionBarForSupportVisionChange(this);
+    modelService.bindActionBarForModelAvailability(this);
 
     ChatInputTextViewer tv = new ChatInputTextViewer(borderedActionBar, chatServiceManager);
     tv.setEditable(true);
@@ -229,15 +231,11 @@ public void textChanged(TextEvent event) {
         if (!isSendButton) {
           return;
         }
-        if (tv.getDocument().get().equals(StringUtils.EMPTY)) {
-          updateButtonState(SendOrCancelButtonStates.SEND_DISABLED);
-        } else {
-          updateButtonState(SendOrCancelButtonStates.SEND_ENABLED);
-        }
+        refreshSendButtonState();
       }
     });
     tv.setSendMessageHandler((message) -> {
-      if (isSendButton) {
+      if (isSendButton && modelAvailable) {
         handleSendMessage();
       }
     });
@@ -424,9 +422,9 @@ public void updateButtonsLayout() {
 
       this.sendToJobButton = UiUtils.createIconButton(this.bottomRightButtonsComposite, SWT.PUSH | SWT.FLAT);
 
-      boolean hasText = !StringUtils.isBlank(this.inputTextViewer.getContent());
-      this.sendToJobButton.setEnabled(hasText);
-      this.sendToJobButton.setImage(hasText ? sendToJobImage : sendToJobDisabledImage);
+      boolean isEnabled = canSend();
+      this.sendToJobButton.setEnabled(isEnabled);
+      this.sendToJobButton.setImage(isEnabled ? sendToJobImage : sendToJobDisabledImage);
       this.sendToJobButton.setToolTipText(Messages.chat_actionBar_sendToJobButton_Tooltip);
       AccessibilityUtils.addAccessibilityNameForUiComponent(this.sendToJobButton,
           Messages.chat_actionBar_sendToJobButton_Tooltip);
@@ -448,7 +446,7 @@ public void widgetSelected(SelectionEvent e) {
       this.sendImage = CopilotImages.getImage(CopilotImages.IMG_CHAT_SEND);
       this.sendDisabledImage = CopilotImages.getImage(CopilotImages.IMG_CHAT_SEND_DISABLED);
       this.btnMsgToggle = UiUtils.createIconButton(bottomRightButtonsComposite, SWT.PUSH | SWT.FLAT);
-      boolean isEnabled = !StringUtils.isBlank(this.inputTextViewer.getContent());
+      boolean isEnabled = canSend();
       this.btnMsgToggle.setEnabled(isEnabled);
       this.btnMsgToggle.setImage(isEnabled ? this.sendImage : this.sendDisabledImage);
       this.btnMsgToggle.setToolTipText(Messages.chat_actionBar_sendButton_Tooltip);
@@ -713,12 +711,38 @@ public void onNewConversation() {
    * Handles the cancel message event.
    */
   public void resetSendButton() {
-    if (this.inputTextViewer.getContent().isEmpty()) {
-      updateButtonState(SendOrCancelButtonStates.SEND_DISABLED);
-    } else {
+    refreshSendButtonState();
+    this.chatServiceManager.getFileToolService().setWorkingSetBarButtonStatus(true);
+  }
+
+  /**
+   * Updates whether a chat model is available. Sending is disabled while no model is available.
+   *
+   * @param available true if an active model is set
+   */
+  public void setModelAvailable(boolean available) {
+    SwtUtils.invokeOnDisplayThreadAsync(() -> {
+      if (isDisposed()) {
+        return;
+      }
+      modelAvailable = available;
+      if (isSendButton) {
+        refreshSendButtonState();
+      }
+      refreshPlaceholder();
+    }, this);
+  }
+
+  private void refreshSendButtonState() {
+    if (canSend()) {
       updateButtonState(SendOrCancelButtonStates.SEND_ENABLED);
+    } else {
+      updateButtonState(SendOrCancelButtonStates.SEND_DISABLED);
     }
-    this.chatServiceManager.getFileToolService().setWorkingSetBarButtonStatus(true);
+  }
+
+  private boolean canSend() {
+    return modelAvailable && !StringUtils.isBlank(this.inputTextViewer.getContent());
   }
 
   /**
@@ -794,11 +818,7 @@ private void handleSendToJob() {
           notifySendWithSlug(workDoneToken, message, UiConstants.GITHUB_COPILOT_CODING_AGENT_SLUG, selectedProjectPath);
         } else {
           // Dialog was cancelled, reset button state based on current input content
-          if (this.inputTextViewer.getContent().isEmpty()) {
-            updateButtonState(SendOrCancelButtonStates.SEND_DISABLED);
-          } else {
-            updateButtonState(SendOrCancelButtonStates.SEND_ENABLED);
-          }
+          refreshSendButtonState();
         }
       }
     }

com.microsoft.copilot.eclipse.ui/src/com/microsoft/copilot/eclipse/ui/chat/ChatInputTextViewer.java

@@ -355,6 +355,9 @@ private void handleSendMessage() {
   }
 
   private String getPlaceholderText() {
+    if (!chatServiceManager.getModelService().hasActiveModel()) {
+      return Messages.chat_actionBar_noModel_placeholder;
+    }
     switch (userPreferenceService.getActiveChatMode()) {
       case Agent:
         // Get the active mode name or ID from observable (not from disk to avoid stale data)