[task-history] Stop rewriting the full task history into VS Code global state

src/core/webview/ClineProvider.ts

@@ -136,8 +136,6 @@ export class ClineProvider
 	private recentTasksCache?: string[]
 	public readonly taskHistoryStore: TaskHistoryStore
 	private taskHistoryStoreInitialized = false
-	private globalStateWriteThroughTimer: ReturnType<typeof setTimeout> | null = null
-	private static readonly GLOBAL_STATE_WRITE_THROUGH_DEBOUNCE_MS = 5000 // 5 seconds
 	private pendingOperations: Map<string, PendingEditOperation> = new Map()
 	private static readonly PENDING_OPERATION_TIMEOUT_MS = 30000 // 30 seconds
 
@@ -166,14 +164,8 @@ export class ClineProvider
 
 		this.updateGlobalState("codebaseIndexModels", EMBEDDING_MODEL_PROFILES)
 
-		// Initialize the per-task file-based history store.
-		// The globalState write-through is debounced separately (not on every mutation)
-		// since per-task files are authoritative and globalState is only for downgrade compat.
-		this.taskHistoryStore = new TaskHistoryStore(this.contextProxy.globalStorageUri.fsPath, {
-			onWrite: async () => {
-				this.scheduleGlobalStateWriteThrough()
-			},
-		})
+		// Initialize the authoritative per-task file-based history store.
+		this.taskHistoryStore = new TaskHistoryStore(this.contextProxy.globalStorageUri.fsPath)
 		this.initializeTaskHistoryStore().catch((error) => {
 			this.log(`Failed to initialize TaskHistoryStore: ${error}`)
 		})
@@ -580,7 +572,6 @@ export class ClineProvider
 		this.skillsManager = undefined
 		this.customModesManager?.dispose()
 		this.taskHistoryStore.dispose()
-		this.flushGlobalStateWriteThrough()
 		this.log("Disposed all disposables")
 		ClineProvider.activeInstances.delete(this)
 
@@ -1260,9 +1251,7 @@ export class ClineProvider
 
 			try {
 				// Update the task history with the new mode first.
-				const taskHistoryItem =
-					this.taskHistoryStore.get(task.taskId) ??
-					(this.getGlobalState("taskHistory") ?? []).find((item) => item.id === task.taskId)
+				const taskHistoryItem = this.getTaskHistoryItem(task.taskId)
 
 				if (taskHistoryItem) {
 					await this.updateTaskHistory({ ...taskHistoryItem, mode: newMode })
@@ -1478,9 +1467,7 @@ export class ClineProvider
 			// been persisted into taskHistory (it will be captured on the next save).
 			task.setTaskApiConfigName(apiConfigName)
 
-			const taskHistoryItem =
-				this.taskHistoryStore.get(task.taskId) ??
-				(this.getGlobalState("taskHistory") ?? []).find((item) => item.id === task.taskId)
+			const taskHistoryItem = this.getTaskHistoryItem(task.taskId)
 
 			if (taskHistoryItem) {
 				await this.updateTaskHistory({ ...taskHistoryItem, apiConfigName })
@@ -1632,15 +1619,26 @@ export class ClineProvider
 
 	// Task history
 
+	private getTaskHistoryItem(id: string): HistoryItem | undefined {
+		const historyItem = this.taskHistoryStore.get(id)
+
+		// Once initialization and migration succeed, the file-backed store is authoritative.
+		// Legacy global state is only a fallback while startup is incomplete or has failed.
+		if (historyItem || this.taskHistoryStoreInitialized) {
+			return historyItem
+		}
+
+		return (this.getGlobalState("taskHistory") ?? []).find((item) => item.id === id)
+	}
+
 	async getTaskWithId(id: string): Promise<{
 		historyItem: HistoryItem
 		taskDirPath: string
 		apiConversationHistoryFilePath: string
 		uiMessagesFilePath: string
 		apiConversationHistory: Anthropic.MessageParam[]
 	}> {
-		const historyItem =
-			this.taskHistoryStore.get(id) ?? (this.getGlobalState("taskHistory") ?? []).find((item) => item.id === id)
+		const historyItem = this.getTaskHistoryItem(id)
 
 		if (!historyItem) {
 			throw new Error("Task not found")
@@ -2276,44 +2274,6 @@ export class ClineProvider
 		return history
 	}
 
-	/**
-	 * Schedule a debounced write-through of task history to globalState.
-	 * Only used for backward compatibility during the transition period.
-	 * Per-task files are authoritative; globalState is the downgrade fallback.
-	 */
-	private scheduleGlobalStateWriteThrough(): void {
-		if (this.globalStateWriteThroughTimer) {
-			clearTimeout(this.globalStateWriteThroughTimer)
-		}
-
-		this.globalStateWriteThroughTimer = setTimeout(async () => {
-			this.globalStateWriteThroughTimer = null
-			try {
-				const items = this.taskHistoryStore.getAll()
-				await this.updateGlobalState("taskHistory", items)
-			} catch (err) {
-				this.log(
-					`[scheduleGlobalStateWriteThrough] Failed: ${err instanceof Error ? err.message : String(err)}`,
-				)
-			}
-		}, ClineProvider.GLOBAL_STATE_WRITE_THROUGH_DEBOUNCE_MS)
-	}
-
-	/**
-	 * Flush any pending debounced globalState write-through immediately.
-	 */
-	private flushGlobalStateWriteThrough(): void {
-		if (this.globalStateWriteThroughTimer) {
-			clearTimeout(this.globalStateWriteThroughTimer)
-			this.globalStateWriteThroughTimer = null
-		}
-
-		const items = this.taskHistoryStore.getAll()
-		this.updateGlobalState("taskHistory", items).catch((err) => {
-			this.log(`[flushGlobalStateWriteThrough] Failed: ${err instanceof Error ? err.message : String(err)}`)
-		})
-	}
-
 	/**
 	 * Broadcasts a task history update to the webview.
 	 * This sends a lightweight message with just the task history, rather than the full state.

src/core/webview/__tests__/ClineProvider.spec.ts

@@ -3419,6 +3419,36 @@ describe("ClineProvider - Comprehensive Edit/Delete Edge Cases", () => {
 	})
 
 	describe("getTaskWithId", () => {
+		it("does not restore a deleted file-backed task from legacy history", async () => {
+			const historyItem = {
+				id: "deleted-task",
+				task: "legacy task",
+				ts: Date.now(),
+				number: 1,
+				tokensIn: 0,
+				tokensOut: 0,
+				totalCost: 0,
+			}
+			vi.mocked(mockContext.globalState.get).mockImplementation((key: string) => {
+				if (key === "taskHistory") {
+					return [historyItem]
+				}
+				return undefined
+			})
+
+			provider.taskHistoryStore["cache"].set(historyItem.id, historyItem)
+			await provider.taskHistoryStore.delete(historyItem.id)
+			provider["taskHistoryStoreInitialized"] = true
+
+			await expect(provider.getTaskWithId(historyItem.id)).rejects.toThrow("Task not found")
+		})
+
+		it("rejects a missing task before file-backed history initialization", async () => {
+			provider["taskHistoryStoreInitialized"] = false
+			vi.mocked(mockContext.globalState.get).mockReturnValue(undefined)
+			await expect(provider.getTaskWithId("cold-start-missing-task")).rejects.toThrow("Task not found")
+		})
+
 		it("returns empty apiConversationHistory when file is missing", async () => {
 			const historyItem = { id: "missing-api-file-task", task: "test task", ts: Date.now() }
 			vi.mocked(mockContext.globalState.get).mockImplementation((key: string) => {

src/core/webview/__tests__/ClineProvider.sticky-mode.spec.ts

@@ -173,6 +173,12 @@ describe("ClineProvider - Sticky Mode", () => {
 	let mockWebviewView: vscode.WebviewView
 	let mockPostMessage: any
 
+	async function seedTaskHistory(items: HistoryItem[]) {
+		for (const item of items) {
+			await provider.taskHistoryStore.upsert(item)
+		}
+	}
+
 	beforeEach(async () => {
 		vi.clearAllMocks()
 
@@ -274,8 +280,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			// Get the actual taskId from the mock
 			const taskId = (mockTask as any).taskId || "test-task-id"
 
-			// Mock getGlobalState to return task history
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: taskId,
 					ts: Date.now(),
@@ -327,8 +333,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			// Add task to provider stack
 			await provider.addClineToStack(mockTask as any)
 
-			// Mock getGlobalState to return task history
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: mockTask.taskId,
 					ts: Date.now(),
@@ -365,8 +371,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			// Get the actual taskId from the mock
 			const taskId = (mockTask as any).taskId || "test-task-id"
 
-			// Mock getGlobalState to return task history
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: taskId,
 					ts: Date.now(),
@@ -488,8 +494,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			// Get the actual taskId from the mock
 			const taskId = (mockTask as any).taskId || "test-task-id"
 
-			// Mock getGlobalState to return task history with our task
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: taskId,
 					ts: Date.now(),
@@ -546,25 +552,21 @@ describe("ClineProvider - Sticky Mode", () => {
 				[parentTaskId]: "architect", // Parent starts with architect mode
 			}
 
-			// Mock getGlobalState to return task history
-			const getGlobalStateMock = vi.spyOn(provider as any, "getGlobalState")
-			getGlobalStateMock.mockImplementation((key) => {
-				if (key === "taskHistory") {
-					return Object.entries(taskModes).map(([id, mode]) => ({
-						id,
-						ts: Date.now(),
-						task: `Task ${id}`,
-						number: 1,
-						tokensIn: 0,
-						tokensOut: 0,
-						cacheWrites: 0,
-						cacheReads: 0,
-						totalCost: 0,
-						mode,
-					}))
-				}
-				// Return empty array for other keys
-				return []
+			// Read task metadata from the authoritative store's test double.
+			vi.spyOn(provider.taskHistoryStore, "get").mockImplementation((id) => {
+				const mode = taskModes[id]
+				return mode === undefined
+					? undefined
+					: {
+							id,
+							ts: Date.now(),
+							task: `Task ${id}`,
+							number: 1,
+							tokensIn: 0,
+							tokensOut: 0,
+							totalCost: 0,
+							mode,
+						}
 			})
 
 			// Mock updateTaskHistory to track mode changes
@@ -775,8 +777,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			// Add task to provider stack
 			await provider.addClineToStack(mockTask as any)
 
-			// Mock getGlobalState to return task history
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: mockTask.taskId,
 					ts: Date.now(),
@@ -842,8 +844,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			// Add task to provider stack
 			await provider.addClineToStack(mockTask as any)
 
-			// Mock getGlobalState
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: mockTask.taskId,
 					ts: Date.now(),
@@ -929,8 +931,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			// Add task to provider stack
 			await provider.addClineToStack(mockTask as any)
 
-			// Mock getGlobalState to return task history
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: mockTask.taskId,
 					ts: Date.now(),
@@ -985,8 +987,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			// Add task to provider stack
 			await provider.addClineToStack(mockTask as any)
 
-			// Mock getGlobalState
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: mockTask.taskId,
 					ts: Date.now(),
@@ -1054,8 +1056,8 @@ describe("ClineProvider - Sticky Mode", () => {
 			await provider.addClineToStack(task2 as any)
 			await provider.addClineToStack(task3 as any)
 
-			// Mock getGlobalState to return all tasks
-			vi.spyOn(provider as any, "getGlobalState").mockReturnValue([
+			// Seed the authoritative file-backed task history.
+			await seedTaskHistory([
 				{
 					id: task1.taskId,
 					ts: Date.now(),

src/core/webview/__tests__/ClineProvider.taskHistory.spec.ts

@@ -332,6 +332,32 @@ describe("ClineProvider Task History Synchronization", () => {
 		return calls.filter((call) => call[0]?.type === type)
 	}
 
+	it("uses per-task files without registering a globalState write-through callback", () => {
+		expect(provider.taskHistoryStore["onWrite"]).toBeUndefined()
+	})
+
+	it("does not write task history to globalState after a history mutation", async () => {
+		vi.mocked(mockContext.globalState.update).mockClear()
+
+		await provider.updateTaskHistory(createHistoryItem({ id: "file-backed-task", task: "File-backed task" }), {
+			broadcast: false,
+		})
+
+		expect(mockContext.globalState.update).not.toHaveBeenCalledWith("taskHistory", expect.anything())
+	})
+
+	it("does not write task history to globalState during disposal", async () => {
+		await provider.updateTaskHistory(
+			createHistoryItem({ id: "disposed-file-backed-task", task: "Disposed file-backed task" }),
+			{ broadcast: false },
+		)
+		vi.mocked(mockContext.globalState.update).mockClear()
+
+		await provider.dispose()
+
+		expect(mockContext.globalState.update).not.toHaveBeenCalledWith("taskHistory", expect.anything())
+	})
+
 	describe("updateTaskHistory", () => {
 		it("broadcasts task history update by default", async () => {
 			await provider.resolveWebviewView(mockWebviewView)