Make console message support more robust to logging in the middle of rendering. (#521)

2 files changed, 299 insertions, 0 deletions

diff --git a/packages/cli/src/ui/hooks/useConsoleMessages.test.ts b/packages/cli/src/ui/hooks/useConsoleMessages.test.ts
new file mode 100644
index 00000000..3b225ecf
--- /dev/null
+++ b/packages/cli/src/ui/hooks/useConsoleMessages.test.ts
@@ -0,0 +1,212 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { act, renderHook } from '@testing-library/react';
+import { useConsoleMessages } from './useConsoleMessages.js';
+import { ConsoleMessageItem } from '../types.js';
+
+// Mock setTimeout and clearTimeout
+vi.useFakeTimers();
+
+describe('useConsoleMessages', () => {
+  it('should initialize with an empty array of console messages', () => {
+    const { result } = renderHook(() => useConsoleMessages());
+    expect(result.current.consoleMessages).toEqual([]);
+  });
+
+  it('should add a new message', () => {
+    const { result } = renderHook(() => useConsoleMessages());
+    const message: ConsoleMessageItem = {
+      type: 'log',
+      content: 'Test message',
+      count: 1,
+    };
+
+    act(() => {
+      result.current.handleNewMessage(message);
+    });
+
+    act(() => {
+      vi.runAllTimers(); // Process the queue
+    });
+
+    expect(result.current.consoleMessages).toEqual([{ ...message, count: 1 }]);
+  });
+
+  it('should consolidate identical consecutive messages', () => {
+    const { result } = renderHook(() => useConsoleMessages());
+    const message: ConsoleMessageItem = {
+      type: 'log',
+      content: 'Test message',
+      count: 1,
+    };
+
+    act(() => {
+      result.current.handleNewMessage(message);
+      result.current.handleNewMessage(message);
+    });
+
+    act(() => {
+      vi.runAllTimers();
+    });
+
+    expect(result.current.consoleMessages).toEqual([{ ...message, count: 2 }]);
+  });
+
+  it('should not consolidate different messages', () => {
+    const { result } = renderHook(() => useConsoleMessages());
+    const message1: ConsoleMessageItem = {
+      type: 'log',
+      content: 'Test message 1',
+      count: 1,
+    };
+    const message2: ConsoleMessageItem = {
+      type: 'error',
+      content: 'Test message 2',
+      count: 1,
+    };
+
+    act(() => {
+      result.current.handleNewMessage(message1);
+      result.current.handleNewMessage(message2);
+    });
+
+    act(() => {
+      vi.runAllTimers();
+    });
+
+    expect(result.current.consoleMessages).toEqual([
+      { ...message1, count: 1 },
+      { ...message2, count: 1 },
+    ]);
+  });
+
+  it('should not consolidate messages if type is different', () => {
+    const { result } = renderHook(() => useConsoleMessages());
+    const message1: ConsoleMessageItem = {
+      type: 'log',
+      content: 'Test message',
+      count: 1,
+    };
+    const message2: ConsoleMessageItem = {
+      type: 'error',
+      content: 'Test message',
+      count: 1,
+    };
+
+    act(() => {
+      result.current.handleNewMessage(message1);
+      result.current.handleNewMessage(message2);
+    });
+
+    act(() => {
+      vi.runAllTimers();
+    });
+
+    expect(result.current.consoleMessages).toEqual([
+      { ...message1, count: 1 },
+      { ...message2, count: 1 },
+    ]);
+  });
+
+  it('should clear console messages', () => {
+    const { result } = renderHook(() => useConsoleMessages());
+    const message: ConsoleMessageItem = {
+      type: 'log',
+      content: 'Test message',
+      count: 1,
+    };
+
+    act(() => {
+      result.current.handleNewMessage(message);
+    });
+
+    act(() => {
+      vi.runAllTimers();
+    });
+
+    expect(result.current.consoleMessages).toHaveLength(1);
+
+    act(() => {
+      result.current.clearConsoleMessages();
+    });
+
+    expect(result.current.consoleMessages).toEqual([]);
+  });
+
+  it('should clear pending timeout on clearConsoleMessages', () => {
+    const { result } = renderHook(() => useConsoleMessages());
+    const message: ConsoleMessageItem = {
+      type: 'log',
+      content: 'Test message',
+      count: 1,
+    };
+
+    act(() => {
+      result.current.handleNewMessage(message); // This schedules a timeout
+    });
+
+    act(() => {
+      result.current.clearConsoleMessages();
+    });
+
+    // Ensure the queue is empty and no more messages are processed
+    act(() => {
+      vi.runAllTimers(); // If timeout wasn't cleared, this would process the queue
+    });
+
+    expect(result.current.consoleMessages).toEqual([]);
+  });
+
+  it('should clear message queue on clearConsoleMessages', () => {
+    const { result } = renderHook(() => useConsoleMessages());
+    const message: ConsoleMessageItem = {
+      type: 'log',
+      content: 'Test message',
+      count: 1,
+    };
+
+    act(() => {
+      // Add a message but don't process the queue yet
+      result.current.handleNewMessage(message);
+    });
+
+    act(() => {
+      result.current.clearConsoleMessages();
+    });
+
+    // Process any pending timeouts (should be none related to message queue)
+    act(() => {
+      vi.runAllTimers();
+    });
+
+    // The consoleMessages should be empty because the queue was cleared before processing
+    expect(result.current.consoleMessages).toEqual([]);
+  });
+
+  it('should cleanup timeout on unmount', () => {
+    const { result, unmount } = renderHook(() => useConsoleMessages());
+    const message: ConsoleMessageItem = {
+      type: 'log',
+      content: 'Test message',
+      count: 1,
+    };
+
+    act(() => {
+      result.current.handleNewMessage(message);
+    });
+
+    unmount();
+
+    // This is a bit indirect. We check that clearTimeout was called.
+    // If clearTimeout was not called, and we run timers, an error might occur
+    // or the state might change, which it shouldn't after unmount.
+    // Vitest's vi.clearAllTimers() or specific checks for clearTimeout calls
+    // would be more direct if available and easy to set up here.
+    // For now, we rely on the useEffect cleanup pattern.
+    expect(vi.getTimerCount()).toBe(0); // Check if all timers are cleared
+  });
+});
diff --git a/packages/cli/src/ui/hooks/useConsoleMessages.ts b/packages/cli/src/ui/hooks/useConsoleMessages.ts
new file mode 100644
index 00000000..90dc6f81
--- /dev/null
+++ b/packages/cli/src/ui/hooks/useConsoleMessages.ts
@@ -0,0 +1,87 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { useCallback, useEffect, useRef, useState } from 'react';
+import { ConsoleMessageItem } from '../types.js';
+
+export interface UseConsoleMessagesReturn {
+  consoleMessages: ConsoleMessageItem[];
+  handleNewMessage: (message: ConsoleMessageItem) => void;
+  clearConsoleMessages: () => void;
+}
+
+export function useConsoleMessages(): UseConsoleMessagesReturn {
+  const [consoleMessages, setConsoleMessages] = useState<ConsoleMessageItem[]>(
+    [],
+  );
+  const messageQueueRef = useRef<ConsoleMessageItem[]>([]);
+  const messageQueueTimeoutRef = useRef<number | null>(null);
+
+  const processMessageQueue = useCallback(() => {
+    if (messageQueueRef.current.length === 0) {
+      return;
+    }
+
+    setConsoleMessages((prevMessages) => {
+      const newMessages = [...prevMessages];
+      messageQueueRef.current.forEach((queuedMessage) => {
+        if (
+          newMessages.length > 0 &&
+          newMessages[newMessages.length - 1].type === queuedMessage.type &&
+          newMessages[newMessages.length - 1].content === queuedMessage.content
+        ) {
+          newMessages[newMessages.length - 1].count =
+            (newMessages[newMessages.length - 1].count || 1) + 1;
+        } else {
+          newMessages.push({ ...queuedMessage, count: 1 });
+        }
+      });
+      return newMessages;
+    });
+
+    messageQueueRef.current = [];
+    messageQueueTimeoutRef.current = null; // Allow next scheduling
+  }, []);
+
+  const scheduleQueueProcessing = useCallback(() => {
+    if (messageQueueTimeoutRef.current === null) {
+      messageQueueTimeoutRef.current = setTimeout(
+        processMessageQueue,
+        0,
+      ) as unknown as number;
+    }
+  }, [processMessageQueue]);
+
+  const handleNewMessage = useCallback(
+    (message: ConsoleMessageItem) => {
+      messageQueueRef.current.push(message);
+      scheduleQueueProcessing();
+    },
+    [scheduleQueueProcessing],
+  );
+
+  const clearConsoleMessages = useCallback(() => {
+    setConsoleMessages([]);
+    if (messageQueueTimeoutRef.current !== null) {
+      clearTimeout(messageQueueTimeoutRef.current);
+      messageQueueTimeoutRef.current = null;
+    }
+    messageQueueRef.current = [];
+  }, []);
+
+  useEffect(
+    () =>
+      // Cleanup on unmount
+      () => {
+        if (messageQueueTimeoutRef.current !== null) {
+          clearTimeout(messageQueueTimeoutRef.current);
+        }
+      },
+    [],
+  );
+
+  return { consoleMessages, handleNewMessage, clearConsoleMessages };
+}