feat: improve error handling in the TUI (#44)

Author: hugodutka

packages/blink/src/cli/run.ts

@@ -67,6 +67,9 @@ export default async function run(
   const manager = new ChatManager({
     chatId: opts?.chat,
     chatsDirectory: chatsDir,
+    onError: (error) => {
+      console.error("Error:", error);
+    },
   });
   manager.setAgent(agent.client);
 
@@ -95,9 +98,6 @@ export default async function run(
 
     // Print final state
     const finalState = manager.getState();
-    if (finalState.error) {
-      console.error("Error:", finalState.error);
-    }
     console.log("Final state:", finalState.messages.pop());
   } finally {
     manager.dispose();

packages/blink/src/local/chat-manager.test.ts

@@ -197,7 +197,6 @@ test("initializes with empty state for non-existent chat", async () => {
   expect(state.messages).toEqual([]);
   expect(state.status).toBe("idle");
   expect(state.streamingMessage).toBeUndefined();
-  expect(state.error).toBeUndefined();
   expect(state.queuedMessages).toEqual([]);
 
   manager.dispose();
@@ -873,126 +872,42 @@ test("watcher onChange does not cause status to flicker during lock release", as
   manager.dispose();
 });
 
-test("error clearing: errors clear when sending new message", async () => {
-  const chatsDir = await mkdtemp(join(tmpdir(), "chat-test-"));
-
-  try {
-    // Create a manager with an agent that will fail
-    const failingAgent: any = {
-      chat: async () => {
-        throw new Error("Test error");
-      },
-    };
-
-    const manager = new ChatManager({
-      chatId: crypto.randomUUID(),
-      chatsDirectory: chatsDir,
-    });
-
-    // Track state changes before sending message
-    let errorSeen = false;
-    let errorCleared = false;
-    const unsubscribe = manager.subscribe((state) => {
-      if (state.error) {
-        errorSeen = true;
-      }
-      if (errorSeen && !state.error) {
-        errorCleared = true;
-      }
-    });
-
-    manager.setAgent(failingAgent);
-
-    // Send a message that will fail
-    const message: StoredMessage = {
-      id: crypto.randomUUID(),
-      created_at: new Date().toISOString(),
-      role: "user",
-      parts: [{ type: "text", text: "Hello" }],
-      mode: "run",
-      metadata: undefined,
-    };
-
-    await manager.sendMessages([message]);
-
-    // Wait for error state
-    await new Promise((resolve) => setTimeout(resolve, 100));
-
-    // Should have seen an error
-    expect(errorSeen).toBe(true);
-    let state = manager.getState();
-    expect(state.status).toBe("error");
-
-    // Now set a working agent
-    const workingAgent = createMockAgent("Success!");
-    manager.setAgent(workingAgent);
-
-    // Send another message
-    const message2: StoredMessage = {
-      id: crypto.randomUUID(),
-      created_at: new Date().toISOString(),
-      role: "user",
-      parts: [{ type: "text", text: "Try again" }],
-      mode: "run",
-      metadata: undefined,
-    };
-
-    await manager.sendMessages([message2]);
-
-    // Wait for completion
-    await new Promise((resolve) => setTimeout(resolve, 300));
+test("onError callback is called when no agent is available", async () => {
+  const chatId = crypto.randomUUID();
 
-    // Error should have been cleared at some point during the lifecycle
-    // This is the key behavior - errors should clear when sending new messages
-    expect(errorCleared).toBe(true);
+  // Track errors via onError callback
+  const errors: string[] = [];
+  const onError = mock((error: string) => {
+    errors.push(error);
+  });
 
-    // Final state should have no error (watcher may still show error status briefly)
-    state = manager.getState();
-    expect(state.error).toBeUndefined();
+  const manager = new ChatManager({
+    chatId,
+    chatsDirectory: tempDir,
+    onError,
+  });
 
-    unsubscribe();
-    manager.dispose();
-  } finally {
-    await rm(chatsDir, { recursive: true, force: true });
-  }
-});
+  // Don't set an agent, so it should fail when we try to send a message
 
-test("error clearing: persisted errors don't load from disk", async () => {
-  const chatsDir = await mkdtemp(join(tmpdir(), "chat-test-"));
-
-  try {
-    const chatId = crypto.randomUUID();
-
-    // Manually create a chat with an error in the store
-    const store = createDiskStore<StoredChat>(chatsDir, "id");
-    const locked = await store.lock(chatId);
-    try {
-      await locked.set({
-        id: chatId,
-        created_at: new Date().toISOString(),
-        updated_at: new Date().toISOString(),
-        messages: [],
-        error: "Old persisted error",
-      });
-    } finally {
-      await locked.release();
-    }
+  // Send a message without an agent
+  const message: StoredMessage = {
+    id: crypto.randomUUID(),
+    created_at: new Date().toISOString(),
+    role: "user",
+    parts: [{ type: "text", text: "Hello" }],
+    mode: "run",
+    metadata: undefined,
+  };
 
-    // Create a new manager - it should clear the persisted error
-    const manager = new ChatManager({
-      chatId,
-      chatsDirectory: chatsDir,
-    });
+  await manager.sendMessages([message]);
 
-    // Wait for initial load
-    await new Promise((resolve) => setTimeout(resolve, 100));
+  // Wait a bit for the error to be processed
+  await new Promise((resolve) => setTimeout(resolve, 100));
 
-    const state = manager.getState();
-    expect(state.error).toBeUndefined(); // Error should be cleared
-    expect(state.loading).toBe(false);
+  // Verify onError was called with the "no agent" error message
+  expect(onError).toHaveBeenCalled();
+  expect(errors.length).toBeGreaterThan(0);
+  expect(errors[0]).toContain("agent is not available");
 
-    manager.dispose();
-  } finally {
-    await rm(chatsDir, { recursive: true, force: true });
-  }
+  manager.dispose();
 });

packages/blink/src/local/chat-manager.ts

@@ -25,7 +25,6 @@ export interface ChatState {
   readonly messages: StoredMessage[];
   readonly status: ChatStatus;
   readonly streamingMessage?: StoredMessage;
-  readonly error?: string;
   readonly loading: boolean;
   readonly queuedMessages: StoredMessage[];
 }
@@ -43,6 +42,10 @@ export interface ChatManagerOptions {
    * Return true to include the message, false to exclude it.
    */
   readonly filterMessages?: (message: StoredMessage) => boolean;
+  /**
+   * Optional callback invoked when an error occurs during chat operations.
+   */
+  readonly onError?: (error: string) => void;
 }
 
 type StateListener = (state: ChatState) => void;
@@ -57,6 +60,7 @@ export class ChatManager {
   private chatStore: Store<StoredChat>;
   private serializeMessage?: (message: UIMessage) => StoredMessage | undefined;
   private filterMessages?: (message: StoredMessage) => boolean;
+  private onError?: (error: string) => void;
 
   private chat: StoredChat;
   private loading = false;
@@ -82,6 +86,7 @@ export class ChatManager {
     this.chatStore = createDiskStore<StoredChat>(options.chatsDirectory, "id");
     this.serializeMessage = options.serializeMessage;
     this.filterMessages = options.filterMessages;
+    this.onError = options.onError;
 
     // Start disk watcher
     this.watcher = createDiskStoreWatcher<StoredChat>(options.chatsDirectory, {
@@ -122,21 +127,14 @@ export class ChatManager {
 
       const diskValue = event.value;
 
-      let newStatus = event.value?.error ? "error" : "idle";
-      if (event.locked) {
-        newStatus = "streaming";
-      }
+      let newStatus: ChatStatus = event.locked ? "streaming" : "idle";
       const shouldEmit =
         this.chat.updated_at !== diskValue?.updated_at ||
         this.status !== newStatus;
 
-      // Clear persisted errors - they're stale from disk
-      this.chat = {
-        ...diskValue,
-        error: undefined,
-      };
+      this.chat = diskValue;
       this.streamingMessage = undefined;
-      this.status = newStatus as ChatStatus;
+      this.status = newStatus;
 
       if (shouldEmit) {
         this.notifyListeners();
@@ -154,14 +152,11 @@ export class ChatManager {
         if (!chat) {
           return;
         }
-        // Clear any persisted errors on load - they're stale
-        this.chat = {
-          ...chat,
-          error: undefined,
-        };
+        this.chat = chat;
       })
       .catch((err) => {
-        this.chat.error = err instanceof Error ? err.message : String(err);
+        const errorMessage = err instanceof Error ? err.message : String(err);
+        this.onError?.(errorMessage);
       })
       .finally(() => {
         this.loading = false;
@@ -190,7 +185,6 @@ export class ChatManager {
       updated_at: this.chat?.updated_at,
       status: this.status,
       streamingMessage: this.streamingMessage,
-      error: this.chat?.error,
       loading: this.loading,
       queuedMessages: this.queue,
     };
@@ -298,22 +292,6 @@ export class ChatManager {
    * Send a message to the agent
    */
   async sendMessages(messages: StoredMessage[]): Promise<void> {
-    // Clear any previous errors when sending a new message (persist to disk)
-    if (this.chat.error) {
-      const locked = await this.chatStore.lock(this.chatId);
-      try {
-        const current = await locked.get();
-        this.chat = {
-          ...current,
-          error: undefined,
-          updated_at: new Date().toISOString(),
-        };
-        await locked.set(this.chat);
-      } finally {
-        await locked.release();
-      }
-    }
-
     this.status = "idle";
     this.notifyListeners();
 
@@ -331,8 +309,6 @@ export class ChatManager {
   }
 
   async start(): Promise<void> {
-    // Clear error when explicitly starting
-    this.chat.error = undefined;
     this.status = "idle";
     this.notifyListeners();
     // Do not await this - it will block the server.
@@ -347,19 +323,16 @@ export class ChatManager {
 
   private async processQueueOrRun(): Promise<void> {
     if (!this.agent) {
-      // Set error state instead of throwing
-      this.chat.error =
+      const errorMessage =
         "The agent is not available. Please wait for the build to succeed.";
-      this.status = "error";
+      this.onError?.(errorMessage);
       this.queue = []; // Clear the queue
-      this.notifyListeners();
       return;
     }
     if (this.isProcessingQueue) {
       return;
     }
     this.isProcessingQueue = true;
-    this.chat.error = undefined;
 
     let locked: LockedStoreEntry<StoredChat> | undefined;
     try {
@@ -501,15 +474,12 @@ export class ChatManager {
         }
       }
     } catch (err: any) {
-      this.chat.error = err instanceof Error ? err.message : String(err);
+      const errorMessage = err instanceof Error ? err.message : String(err);
+      this.onError?.(errorMessage);
     } finally {
       this.isProcessingQueue = false;
       this.streamingMessage = undefined;
-      if (this.chat.error) {
-        this.status = "error";
-      } else {
-        this.status = "idle";
-      }
+      this.status = "idle";
 
       if (locked) {
         this.chat.updated_at = new Date().toISOString();

packages/blink/src/local/types.ts

@@ -7,7 +7,6 @@ export interface StoredChat {
   created_at: string;
   updated_at: string;
   messages: StoredMessage[];
-  error?: string;
 }
 
 export type StoredMessageMetadata = {

packages/blink/src/react/use-chat.test.tsx

@@ -23,7 +23,6 @@ const Harness: React.FC<HarnessProps> = ({ options, onUpdate }) => {
     result.status,
     result.messages.length,
     result.streamingMessage,
-    result.error,
     result.queuedMessages.length,
   ]);
   return null;
@@ -106,7 +105,6 @@ test("initializes with empty state for non-existent chat", async () => {
   expect(r.messages).toEqual([]);
   expect(r.status).toBe("idle");
   expect(r.streamingMessage).toBeUndefined();
-  expect(r.error).toBeUndefined();
 
   app.unmount();
 });