fix: prevent race condition when switching modes rapidly with ctrl+.

- Added debouncing (150ms) to mode switching functions to prevent rapid consecutive switches
- Added isModeSwitching state flag to prevent concurrent mode switches in both UI and backend
- Updated tests to account for debounce delay
- Fixes issue where rapidly pressing ctrl+. could assign wrong model to mode

Fixes #6764

src/core/webview/ClineProvider.ts

@@ -112,6 +112,7 @@ export class ClineProvider
 	protected mcpHub?: McpHub // Change from private to protected
 	private marketplaceManager: MarketplaceManager
 	private mdmService?: MdmService
+	private isModeSwitching = false
 
 	public isViewLaunched = false
 	public settingsImportedAt?: number
@@ -956,6 +957,23 @@ export class ClineProvider
 	 * @param newMode The mode to switch to
 	 */
 	public async handleModeSwitch(newMode: Mode) {
+		// Prevent concurrent mode switches
+		if (this.isModeSwitching) {
+			this.log(`Mode switch already in progress, ignoring switch to ${newMode}`)
+			return
+		}
+
+		this.isModeSwitching = true
+
+		try {
+			await this.performModeSwitch(newMode)
+		} finally {
+			// Always reset the flag, even if an error occurs
+			this.isModeSwitching = false
+		}
+	}
+
+	private async performModeSwitch(newMode: Mode) {
 		const cline = this.getCurrentCline()
 
 		if (cline) {

webview-ui/src/components/chat/ChatView.tsx

@@ -179,6 +179,7 @@ const ChatViewComponent: React.ForwardRefRenderFunction<ChatViewRef, ChatViewPro
 	const [showCheckpointWarning, setShowCheckpointWarning] = useState<boolean>(false)
 	const [isCondensing, setIsCondensing] = useState<boolean>(false)
 	const [showAnnouncementModal, setShowAnnouncementModal] = useState(false)
+	const [isModeSwitching, setIsModeSwitching] = useState<boolean>(false)
 	const everVisibleMessagesTsRef = useRef<LRUCache<number, boolean>>(
 		new LRUCache({
 			max: 100,
@@ -1456,6 +1457,14 @@ const ChatViewComponent: React.ForwardRefRenderFunction<ChatViewRef, ChatViewPro
 	// Function to switch to a specific mode
 	const switchToMode = useCallback(
 		(modeSlug: string): void => {
+			// Prevent concurrent mode switches
+			if (isModeSwitching) {
+				return
+			}
+
+			// Set flag to prevent concurrent switches
+			setIsModeSwitching(true)
+
 			// Update local state and notify extension to sync mode change
 			setMode(modeSlug)
 
@@ -1464,8 +1473,13 @@ const ChatViewComponent: React.ForwardRefRenderFunction<ChatViewRef, ChatViewPro
 				type: "mode",
 				text: modeSlug,
 			})
+
+			// Reset the flag after a short delay to allow the mode switch to complete
+			setTimeout(() => {
+				setIsModeSwitching(false)
+			}, 300)
 		},
-		[setMode],
+		[setMode, isModeSwitching],
 	)
 
 	const handleSuggestionClickInRow = useCallback(
@@ -1714,23 +1728,31 @@ const ChatViewComponent: React.ForwardRefRenderFunction<ChatViewRef, ChatViewPro
 		tSettings,
 	])
 
-	// Function to handle mode switching
-	const switchToNextMode = useCallback(() => {
-		const allModes = getAllModes(customModes)
-		const currentModeIndex = allModes.findIndex((m) => m.slug === mode)
-		const nextModeIndex = (currentModeIndex + 1) % allModes.length
-		// Update local state and notify extension to sync mode change
-		switchToMode(allModes[nextModeIndex].slug)
-	}, [mode, customModes, switchToMode])
+	// Function to handle mode switching with debouncing
+	const switchToNextMode = useMemo(
+		() =>
+			debounce(() => {
+				const allModes = getAllModes(customModes)
+				const currentModeIndex = allModes.findIndex((m) => m.slug === mode)
+				const nextModeIndex = (currentModeIndex + 1) % allModes.length
+				// Update local state and notify extension to sync mode change
+				switchToMode(allModes[nextModeIndex].slug)
+			}, 150),
+		[mode, customModes, switchToMode],
+	)
 
-	// Function to handle switching to previous mode
-	const switchToPreviousMode = useCallback(() => {
-		const allModes = getAllModes(customModes)
-		const currentModeIndex = allModes.findIndex((m) => m.slug === mode)
-		const previousModeIndex = (currentModeIndex - 1 + allModes.length) % allModes.length
-		// Update local state and notify extension to sync mode change
-		switchToMode(allModes[previousModeIndex].slug)
-	}, [mode, customModes, switchToMode])
+	// Function to handle switching to previous mode with debouncing
+	const switchToPreviousMode = useMemo(
+		() =>
+			debounce(() => {
+				const allModes = getAllModes(customModes)
+				const currentModeIndex = allModes.findIndex((m) => m.slug === mode)
+				const previousModeIndex = (currentModeIndex - 1 + allModes.length) % allModes.length
+				// Update local state and notify extension to sync mode change
+				switchToMode(allModes[previousModeIndex].slug)
+			}, 150),
+		[mode, customModes, switchToMode],
+	)
 
 	// Add keyboard event handler
 	const handleKeyDown = useCallback(
@@ -1752,13 +1774,20 @@ const ChatViewComponent: React.ForwardRefRenderFunction<ChatViewRef, ChatViewPro
 		[switchToNextMode, switchToPreviousMode],
 	)
 
-	// Add event listener
+	// Add event listener and cleanup debounced functions
 	useEffect(() => {
 		window.addEventListener("keydown", handleKeyDown)
 		return () => {
 			window.removeEventListener("keydown", handleKeyDown)
+			// Cancel any pending debounced calls when unmounting
+			if (typeof (switchToNextMode as any).cancel === "function") {
+				;(switchToNextMode as any).cancel()
+			}
+			if (typeof (switchToPreviousMode as any).cancel === "function") {
+				;(switchToPreviousMode as any).cancel()
+			}
 		}
-	}, [handleKeyDown])
+	}, [handleKeyDown, switchToNextMode, switchToPreviousMode])
 
 	useImperativeHandle(ref, () => ({
 		acceptInput: () => {

webview-ui/src/components/chat/__tests__/ChatView.keyboard-fix.spec.tsx

@@ -162,8 +162,8 @@ describe("ChatView - Keyboard Shortcut Fix for Dvorak", () => {
 			shiftKey: false,
 		})
 
-		// Wait for event to be processed
-		await new Promise((resolve) => setTimeout(resolve, 50))
+		// Wait for event to be processed and debounce delay (150ms)
+		await new Promise((resolve) => setTimeout(resolve, 200))
 
 		// Check if mode switch was triggered
 		const callsAfterPeriod = (vscode.postMessage as any).mock.calls
@@ -183,7 +183,7 @@ describe("ChatView - Keyboard Shortcut Fix for Dvorak", () => {
 		})
 
 		// Wait for event to be processed
-		await new Promise((resolve) => setTimeout(resolve, 50))
+		await new Promise((resolve) => setTimeout(resolve, 200))
 
 		// Check that NO mode switch was triggered
 		const callsAfterV = (vscode.postMessage as any).mock.calls
@@ -244,8 +244,8 @@ describe("ChatView - Keyboard Shortcut Fix for Dvorak", () => {
 			shiftKey: false,
 		})
 
-		// Wait for event to be processed
-		await new Promise((resolve) => setTimeout(resolve, 50))
+		// Wait for event to be processed and debounce delay (150ms)
+		await new Promise((resolve) => setTimeout(resolve, 200))
 
 		// Check if mode switch was triggered
 		const calls = (vscode.postMessage as any).mock.calls
@@ -277,8 +277,8 @@ describe("ChatView - Keyboard Shortcut Fix for Dvorak", () => {
 			shiftKey: true, // Should go to previous mode
 		})
 
-		// Wait for event to be processed
-		await new Promise((resolve) => setTimeout(resolve, 50))
+		// Wait for event to be processed and debounce delay (150ms)
+		await new Promise((resolve) => setTimeout(resolve, 200))
 
 		// Check if mode switch was triggered
 		const calls = (vscode.postMessage as any).mock.calls