test(task): guard immediate clean state on start

Verify stale webview messages are cleared and posted through the immediate state path before the first task message. This keeps task startup outside the throttled update path.

Signed-off-by: JunyongParkDev <jun94.park@samsung.com>

Author: JunyongParkDev

src/core/task/__tests__/Task.spec.ts

@@ -27,6 +27,8 @@ import type { ApiMessage } from "../../task-persistence"
 
 type TaskTestAccess = {
 	getSystemPrompt: () => Promise<string>
+	getEnabledMcpToolsCount: () => Promise<{ enabledToolCount: number; enabledServerCount: number }>
+	initiateTaskLoop: (userContent: Anthropic.Messages.ContentBlockParam[]) => Promise<void>
 	startTask: (task?: string, images?: string[]) => Promise<void>
 	resumeTaskFromHistory: () => Promise<void>
 	presentAssistantMessageSafe: () => void
@@ -2849,6 +2851,50 @@ describe("Cline", () => {
 		})
 	})
 
+	describe("startTask", () => {
+		it("posts a clean state immediately before adding the first task message", async () => {
+			const task = new Task({
+				provider: mockProvider,
+				apiConfiguration: mockApiConfig,
+				task: "new task",
+				startTask: false,
+			})
+			const taskAccess = getTaskTestAccess(task)
+
+			task.clineMessages = [{ ts: 1, type: "say", say: "text", text: "stale message" }]
+
+			let resolvePostState: (() => void) | undefined
+			const pendingPostState = new Promise<void>((resolve) => {
+				resolvePostState = resolve
+			})
+			const postStateSpy = vi
+				.mocked(mockProvider.postStateToWebviewWithoutTaskHistory)
+				.mockImplementationOnce(async () => {
+					expect(task.clineMessages).toEqual([])
+					await pendingPostState
+				})
+			const saySpy = vi.spyOn(task, "say").mockResolvedValue(undefined)
+			vi.spyOn(taskAccess, "getEnabledMcpToolsCount").mockResolvedValue({
+				enabledToolCount: 0,
+				enabledServerCount: 0,
+			})
+			const initiateTaskLoopSpy = vi.spyOn(taskAccess, "initiateTaskLoop").mockResolvedValue(undefined)
+
+			const startPromise = taskAccess.startTask("new task")
+
+			expect(postStateSpy).toHaveBeenCalledTimes(1)
+			expect(mockProvider.postStateToWebviewThrottled).not.toHaveBeenCalled()
+			expect(saySpy).not.toHaveBeenCalled()
+
+			resolvePostState?.()
+			await startPromise
+
+			expect(saySpy).toHaveBeenCalledOnce()
+			expect(saySpy).toHaveBeenCalledWith("text", "new task", undefined)
+			expect(initiateTaskLoopSpy).toHaveBeenCalledOnce()
+		})
+	})
+
 	describe("start()", () => {
 		it("should be a no-op if the task was already started in the constructor", () => {
 			const task = new Task({