refactor: make say() transactional

Refactors the say() method in Task.ts to ensure message updates are atomic.

The mutation logic for the last message is moved inside the modifyClineMessages() callback. This makes the find, update, and save operations a single atomic transaction, preventing race conditions and ensuring data integrity.

Signed-off-by: Eric Wheeler <[email protected]>

Author: Eric Wheeler

src/core/task/Task.ts

@@ -726,7 +726,13 @@ export class Task extends EventEmitter<ClineEvents> {
 		}
 
 		if (partial !== undefined) {
-			const lastMessage = this.clineMessages.at(-1)
+			let lastMessage = this.clineMessages.at(-1)
+
+			if (lastMessage === undefined) {
+				throw new Error(
+					`[RooCode#say] task ${this.taskId}.${this.instanceId}: clineMessages is empty? Please report this bug.`,
+				)
+			}
 
 			const isUpdatingPreviousPartial =
 				lastMessage && lastMessage.partial && lastMessage.type === "say" && lastMessage.say === type
@@ -762,23 +768,25 @@ export class Task extends EventEmitter<ClineEvents> {
 				// This is the complete version of a previously partial
 				// message, so replace the partial with the complete version.
 				if (isUpdatingPreviousPartial) {
-					if (!options.isNonInteractive) {
-						this.lastMessageTs = lastMessage.ts
-					}
-
-					lastMessage.text = text
-					lastMessage.images = images
-					lastMessage.partial = false
-					lastMessage.progressStatus = progressStatus
-
 					// Instead of streaming partialMessage events, we do a save
 					// and post like normal to persist to disk.
-					await this.modifyClineMessages(async () => {
-						return this.clineMessages
-					})
+					await this.modifyClineMessages(async (messages) => {
+						lastMessage = messages.at(-1) // update ref for transaction
+						if (lastMessage) {
+							if (!options.isNonInteractive) {
+								this.lastMessageTs = lastMessage.ts
+							}
 
-					// More performant than an entire `postStateToWebview`.
-					this.updateClineMessage(lastMessage)
+							lastMessage.text = text
+							lastMessage.images = images
+							lastMessage.partial = false
+							lastMessage.progressStatus = progressStatus
+
+							// More performant than an entire `postStateToWebview`.
+							this.updateClineMessage(lastMessage)
+						}
+						return messages
+					})
 				} else {
 					// This is a new and complete message, so add it like normal.
 					const sayTs = Date.now()