From 1918d9cfe65b483f1fdd0c0a4a1932b4cc4b74c6 Mon Sep 17 00:00:00 2001
From: Roo Code <roomote@roocode.com>
Date: Mon, 12 Jan 2026 11:17:31 +0000
Subject: [PATCH] fix: handle undefined inputValue in ChatTextArea to prevent
 crash

Add defensive null/undefined checks using nullish coalescing operator
to handle cases where inputValue is undefined, such as when Gemini
model returns blank responses.

Fixes #10631
---
 .../src/components/chat/ChatTextArea.tsx      | 25 +++++++++++--------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/webview-ui/src/components/chat/ChatTextArea.tsx b/webview-ui/src/components/chat/ChatTextArea.tsx
index dd3d0d4c663..099ac7c6379 100644
--- a/webview-ui/src/components/chat/ChatTextArea.tsx
+++ b/webview-ui/src/components/chat/ChatTextArea.tsx
@@ -242,7 +242,7 @@ export const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 		}, [selectedType, searchQuery])
 
 		const handleEnhancePrompt = useCallback(() => {
-			const trimmedInput = inputValue.trim()
+			const trimmedInput = (inputValue ?? "").trim()
 
 			if (trimmedInput) {
 				setIsEnhancingPrompt(true)
@@ -256,7 +256,7 @@ export const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 
 		// Memoized check for whether the input has content (text or images)
 		const hasInputContent = useMemo(() => {
-			return inputValue.trim().length > 0 || selectedImages.length > 0
+			return (inputValue ?? "").trim().length > 0 || selectedImages.length > 0
 		}, [inputValue, selectedImages])
 
 		// Compute the key combination text for the send button tooltip based on enterBehavior
@@ -506,8 +506,9 @@ export const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 				}
 
 				if (event.key === "Backspace" && !isComposing) {
-					const charBeforeCursor = inputValue[cursorPosition - 1]
-					const charAfterCursor = inputValue[cursorPosition + 1]
+					const safeInputValue = inputValue ?? ""
+					const charBeforeCursor = safeInputValue[cursorPosition - 1]
+					const charAfterCursor = safeInputValue[cursorPosition + 1]
 
 					const charBeforeIsWhitespace =
 						charBeforeCursor === " " || charBeforeCursor === "\n" || charBeforeCursor === "\r\n"
@@ -519,7 +520,7 @@ export const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 					if (
 						charBeforeIsWhitespace &&
 						// "$" is added to ensure the match occurs at the end of the string.
-						inputValue.slice(0, cursorPosition - 1).match(new RegExp(mentionRegex.source + "$"))
+						safeInputValue.slice(0, cursorPosition - 1).match(new RegExp(mentionRegex.source + "$"))
 					) {
 						const newCursorPosition = cursorPosition - 1
 						// If mention is followed by another word, then instead
@@ -534,9 +535,9 @@ export const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 						setCursorPosition(newCursorPosition)
 						setJustDeletedSpaceAfterMention(true)
 					} else if (justDeletedSpaceAfterMention) {
-						const { newText, newPosition } = removeMention(inputValue, cursorPosition)
-
-						if (newText !== inputValue) {
+						const { newText, newPosition } = removeMention(safeInputValue, cursorPosition)
+		
+						if (newText !== safeInputValue) {
 							event.preventDefault()
 							setInputValue(newText)
 							setIntendedCursorPosition(newPosition) // Store the new cursor position in state
@@ -674,8 +675,9 @@ export const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 				if (urlRegex.test(pastedText.trim())) {
 					e.preventDefault()
 					const trimmedUrl = pastedText.trim()
+					const safeInputValue = inputValue ?? ""
 					const newValue =
-						inputValue.slice(0, cursorPosition) + trimmedUrl + " " + inputValue.slice(cursorPosition)
+						safeInputValue.slice(0, cursorPosition) + trimmedUrl + " " + safeInputValue.slice(cursorPosition)
 					setInputValue(newValue)
 					const newCursorPosition = cursorPosition + trimmedUrl.length + 1
 					setCursorPosition(newCursorPosition)
@@ -820,7 +822,8 @@ export const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 
 					if (lines.length > 0) {
 						// Process each line as a separate file path
-						let newValue = inputValue.slice(0, cursorPosition)
+						const safeInputValue = inputValue ?? ""
+						let newValue = safeInputValue.slice(0, cursorPosition)
 						let totalLength = 0
 
 						// Using a standard for loop instead of forEach for potential performance gains.
@@ -839,7 +842,7 @@ export const ChatTextArea = forwardRef<HTMLTextAreaElement, ChatTextAreaProps>(
 						}
 
 						// Add space after the last mention and append the rest of the input
-						newValue += " " + inputValue.slice(cursorPosition)
+						newValue += " " + safeInputValue.slice(cursorPosition)
 						totalLength += 1
 
 						setInputValue(newValue)