fix(webview) searchFiles memory leak / WebUI Gray Screen

packages/types/src/vscode-extension-host.ts

@@ -37,7 +37,12 @@ export interface ExtensionMessage {
 		| "theme"
 		| "workspaceUpdated"
 		| "invoke"
-		| "messageUpdated"
+		| "clineMessageAppended"
+		| "clineMessageUpdated"
+		| "clineMessagesSnapshotStart"
+		| "clineMessagesSnapshotChunk"
+		| "clineMessagesSnapshotEnd"
+		| "messageUpdated" // Legacy: a patched webview requests a full resync instead of applying this.
 		| "mcpServers"
 		| "enhancedPrompt"
 		| "commitSearchResults"
@@ -138,7 +143,13 @@ export interface ExtensionMessage {
 		isActive: boolean
 		path?: string
 	}>
+	taskId?: string
 	clineMessage?: ClineMessage
+	clineMessages?: ClineMessage[]
+	clineMessagesSeq?: number
+	snapshotId?: string
+	snapshotStartIndex?: number
+	snapshotTotal?: number
 	routerModels?: RouterModels
 	openAiModels?: string[]
 	ollamaModels?: ModelRecord
@@ -334,7 +345,11 @@ export type ExtensionState = Pick<
 	lockApiConfigAcrossModes?: boolean
 	version: string
 	clineMessages: ClineMessage[]
-	currentTaskId?: string
+	/**
+	 * Focused task identity. Omitted means this partial state update does not
+	 * change task focus; null authoritatively means no task is focused.
+	 */
+	currentTaskId?: string | null
 	currentTaskItem?: HistoryItem
 	currentTaskTodos?: TodoItem[] // Initial todos for the current task
 	apiConfiguration: ProviderSettings
@@ -426,10 +441,9 @@ export type ExtensionState = Pick<
 	arch?: string
 
 	/**
-	 * Monotonically increasing sequence number for clineMessages state pushes.
-	 * When present, the frontend should only apply clineMessages from a state push
-	 * if its seq is greater than the last applied seq. This prevents stale state
-	 * (captured during async getStateToPostToWebview) from overwriting newer messages.
+	 * Last sequence applied by the dedicated task-scoped transcript transport.
+	 * Generic `state` messages intentionally omit this field and `clineMessages`;
+	 * snapshots and append/update messages carry both transcript data and sequence.
 	 */
 	clineMessagesSeq?: number
 }
@@ -646,8 +660,11 @@ export interface WebviewMessage {
 		| "openRuleFile"
 		| "openRulesDirectory"
 		| "themeFixtureProbeResponse"
+		| "requestClineMessagesResync"
 	text?: string
 	taskId?: string
+	expectedSeq?: number
+	receivedSeq?: number
 	editedMessageContent?: string
 	tab?: "settings" | "history" | "mcp" | "modes" | "chat" | "marketplace" | "cloud"
 	disabled?: boolean

src/__tests__/helpers/provider-stub.ts

@@ -5,7 +5,9 @@ import { type Task } from "../../core/task/Task"
 type ProviderStubFields = {
 	delegationTransitionLocks?: Map<string, Promise<void>>
 	cancelledDelegationChildIds?: Set<string>
+	clineMessagesSeqByTaskId?: Map<string, number>
 	log?: ReturnType<typeof vi.fn>
+	syncFocusedTaskToWebview?: ReturnType<typeof vi.fn>
 	taskHistoryStore?: { get: (id: string) => unknown }
 	taskRegistry?: TaskRegistry
 	clineStack?: Task[]
@@ -36,7 +38,9 @@ export function makeProviderStub<T extends object>(stub: T): ClineProvider {
 	const proto = ClineProvider.prototype as unknown as PrivateProviderMethods
 	s.delegationTransitionLocks ??= new Map()
 	s.cancelledDelegationChildIds ??= new Set()
+	s.clineMessagesSeqByTaskId ??= new Map()
 	s.log ??= vi.fn()
+	s.syncFocusedTaskToWebview ??= vi.fn().mockResolvedValue(undefined)
 	s.taskHistoryStore ??= { get: () => undefined }
 
 	// Convert legacy clineStack array into a TaskRegistry

src/__tests__/single-open-invariant.spec.ts

@@ -269,6 +269,7 @@ describe("Single-open-task invariant", () => {
 			taskScheduler: { schedule: schedulespy },
 			taskEventListeners: new WeakMap(),
 			performPreparationTasks: vi.fn().mockResolvedValue(undefined),
+			syncFocusedTaskToWebview: vi.fn().mockResolvedValue(undefined),
 			context: { extension: { packageJSON: {} }, globalStorageUri: { fsPath: "/tmp" } },
 			contextProxy: {
 				extensionUri: {},
@@ -341,6 +342,7 @@ describe("Single-open-task invariant", () => {
 			taskScheduler: { schedule: schedulespy },
 			taskEventListeners: new WeakMap(),
 			performPreparationTasks: vi.fn().mockResolvedValue(undefined),
+			syncFocusedTaskToWebview: vi.fn().mockResolvedValue(undefined),
 			context: { extension: { packageJSON: {} }, globalStorageUri: { fsPath: "/tmp" } },
 			contextProxy: {
 				extensionUri: {},

src/core/task/Task.ts

@@ -170,6 +170,7 @@ function queuedResponseForAsk(type: ClineAsk, text?: string): QueuedAskResolutio
 
 const FORCED_CONTEXT_REDUCTION_PERCENT = 75 // Keep 75% of context (remove 25%) on context window errors
 const MAX_CONTEXT_WINDOW_RETRIES = 3 // Maximum retries for context window errors
+const PARTIAL_MESSAGE_UPDATE_DEBOUNCE_MS = 500
 
 export interface TaskOptions extends CreateTaskOptions {
 	provider: ClineProvider
@@ -477,6 +478,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 	// Token Usage Throttling - Debounced emit function
 	private readonly TOKEN_USAGE_EMIT_INTERVAL_MS = 2000 // 2 seconds
 	private debouncedEmitTokenUsage: ReturnType<typeof debounce>
+	private debouncedPostPartialMessageUpdate: ReturnType<typeof debounce>
 
 	// Historical cloud sync tracking retained only to avoid task resume churn.
 	private cloudSyncedMessageTimestamps: Set<number> = new Set()
@@ -640,6 +642,20 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 			this.TOKEN_USAGE_EMIT_INTERVAL_MS,
 			{ leading: true, trailing: true, maxWait: this.TOKEN_USAGE_EMIT_INTERVAL_MS },
 		)
+		this.debouncedPostPartialMessageUpdate = debounce(
+			(message: ClineMessage) => {
+				const provider = this.providerRef.deref()
+				if (!provider) {
+					return
+				}
+
+				void provider.postClineMessageUpdated(this.taskId, message).catch((error) => {
+					console.error("[Task#updateClineMessage] incremental post failed:", error)
+				})
+			},
+			PARTIAL_MESSAGE_UPDATE_DEBOUNCE_MS,
+			{ leading: false, trailing: true },
+		)
 
 		onCreated?.(this)
 
@@ -1148,20 +1164,10 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 	private async addToClineMessages(message: ClineMessage) {
 		this.clineMessages.push(message)
 		const provider = this.providerRef.deref()
-		// Unanswered asks must reach the webview before Message listeners can respond against its state.
-		const requiresImmediateState =
-			message.partial === true || (message.type === "ask" && message.isAnswered !== true)
 		try {
-			await provider?.postStateToWebviewThrottled()
+			await provider?.postClineMessageAppended(this.taskId, message)
 		} catch (error) {
-			console.error("[Task#addToClineMessages] postStateToWebviewThrottled failed:", error)
-		}
-		if (requiresImmediateState) {
-			try {
-				await provider?.flushPostStateToWebviewThrottled()
-			} catch (error) {
-				console.error("[Task#addToClineMessages] flushPostStateToWebviewThrottled failed:", error)
-			}
+			console.error("[Task#addToClineMessages] incremental post failed:", error)
 		}
 		this.emit(RooCodeEventName.Message, { action: "created", message })
 		await this.saveClineMessages()
@@ -1191,11 +1197,16 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 				this.cloudSyncedMessageTimestamps.add(msg.ts)
 			}
 		}
+		await this.providerRef.deref()?.postClineMessagesSnapshot(this.taskId, { bumpSeq: true })
 	}
 
 	private async updateClineMessage(message: ClineMessage) {
-		const provider = this.providerRef.deref()
-		await provider?.postMessageToWebview({ type: "messageUpdated", clineMessage: message })
+		if (message.partial === true) {
+			this.debouncedPostPartialMessageUpdate(message)
+		} else {
+			this.debouncedPostPartialMessageUpdate.cancel()
+			await this.providerRef.deref()?.postClineMessageUpdated(this.taskId, message)
+		}
 		this.emit(RooCodeEventName.Message, { action: "updated", message })
 
 		// Check if we should sync to cloud and haven't already synced this message
@@ -1288,7 +1299,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 
 		let askTs: number
 
-		// Resolve auto-approval before adding the message so the state snapshot
+		// Resolve auto-approval before adding the message so the incremental append
 		// sent to the webview already carries isAnswered:true when the ask will
 		// be immediately resolved. This eliminates the race between the state
 		// update (which shows approval buttons) and the former separate
@@ -1322,10 +1333,8 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 					lastMessage.partial = partial
 					lastMessage.progressStatus = progressStatus
 					lastMessage.isProtected = isProtected
-					// TODO: Be more efficient about saving and posting only new
-					// data or one whole message at a time so ignore partial for
-					// saves, and only post parts of partial message instead of
-					// whole array in new listener.
+					// Persist partial messages only when they become complete; the
+					// dedicated transport can still update one in-memory message at a time.
 					// Fire-and-forget: the webview post is internally guarded, but
 					// the `RooCodeEventName.Message` emit can synchronously throw
 					// if any consumer-attached listener does, which would surface
@@ -1578,6 +1587,9 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 			if (lastFollowUpIndex !== -1) {
 				// Mark this follow-up as answered
 				this.clineMessages[lastFollowUpIndex].isAnswered = true
+				void this.updateClineMessage(this.clineMessages[lastFollowUpIndex]).catch((error) => {
+					console.error("[Task#handleWebviewAskResponse] follow-up delta failed:", error)
+				})
 				// Save the updated messages
 				this.saveClineMessages().catch((error) => {
 					console.error("Failed to save answered follow-up state:", error)
@@ -2053,7 +2065,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 			// The todo list is already set in the constructor if initialTodos were provided
 			// No need to add any messages - the todoList property is already set
 
-			await this.providerRef.deref()?.postStateToWebviewWithoutTaskHistory()
+			await this.providerRef.deref()?.postClineMessagesSnapshot(this.taskId, { bumpSeq: true })
 
 			await this.say("text", task, images)
 
@@ -2204,7 +2216,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 
 			this.isInitialized = true
 
-			const { response, text, images } = await this.ask(askType) // Calls `postStateToWebview`.
+			const { response, text, images } = await this.ask(askType)
 
 			let responseText: string | undefined
 			let responseImages: string[] | undefined
@@ -2516,6 +2528,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 
 	public dispose(): void {
 		console.log(`[Task#dispose] disposing task ${this.taskId}.${this.instanceId}`)
+		this.debouncedPostPartialMessageUpdate.cancel()
 
 		// Stop the idle telemetry check and report any unflushed activity as a
 		// shutdown installment, so a task torn down mid-work (panel closed, task
@@ -2897,7 +2910,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 			} satisfies ClineApiReqInfo)
 
 			await this.saveClineMessages()
-			await this.providerRef.deref()?.postStateToWebviewWithoutTaskHistory()
+			await this.updateClineMessage(this.clineMessages[lastApiReqIndex])
 
 			try {
 				let cacheWriteTokens = 0
@@ -2968,12 +2981,16 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 					if (lastMessage && lastMessage.partial) {
 						// lastMessage.ts = Date.now() DO NOT update ts since it is used as a key for virtuoso list
 						lastMessage.partial = false
-						// instead of streaming partialMessage events, we do a save and post like normal to persist to disk
+						await this.updateClineMessage(lastMessage)
 					}
 
 					// Update `api_req_started` to have cancelled and cost, so that
 					// we can display the cost of the partial stream and the cancellation reason
 					updateApiReqMsg(cancelReason, streamingFailedMessage)
+					const apiRequestMessage = this.clineMessages[lastApiReqIndex]
+					if (apiRequestMessage) {
+						await this.updateClineMessage(apiRequestMessage)
+					}
 					await this.saveClineMessages()
 
 					// Signals to provider that it can retrieve the saved messages
@@ -3651,7 +3668,6 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 				}
 
 				await this.saveClineMessages()
-				await this.providerRef.deref()?.postStateToWebviewWithoutTaskHistory()
 
 				// No legacy text-stream tool parser state to reset.
 

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

@@ -285,6 +285,9 @@ describe("Task persistence", () => {
 		mockProvider.postMessageToWebview = vi.fn().mockResolvedValue(undefined)
 		mockProvider.postStateToWebview = vi.fn().mockResolvedValue(undefined)
 		mockProvider.postStateToWebviewWithoutTaskHistory = vi.fn().mockResolvedValue(undefined)
+		mockProvider.postClineMessageAppended = vi.fn().mockResolvedValue(undefined)
+		mockProvider.postClineMessageUpdated = vi.fn().mockResolvedValue(undefined)
+		mockProvider.postClineMessagesSnapshot = vi.fn().mockResolvedValue(undefined)
 		mockProvider.updateTaskHistory = vi.fn().mockResolvedValue(undefined)
 		mockProvider.log = vi.fn()
 	})