fix: prevent parent task state loss during orchestrator delegation

src/core/task-persistence/__tests__/apiMessages.spec.ts

@@ -0,0 +1,86 @@
+// cd src && npx vitest run core/task-persistence/__tests__/apiMessages.spec.ts
+
+import * as os from "os"
+import * as path from "path"
+import * as fs from "fs/promises"
+
+import { readApiMessages } from "../apiMessages"
+
+let tmpBaseDir: string
+
+beforeEach(async () => {
+	tmpBaseDir = await fs.mkdtemp(path.join(os.tmpdir(), "roo-test-api-"))
+})
+
+describe("apiMessages.readApiMessages", () => {
+	it("returns empty array when api_conversation_history.json contains invalid JSON", async () => {
+		const taskId = "task-corrupt-api"
+		const taskDir = path.join(tmpBaseDir, "tasks", taskId)
+		await fs.mkdir(taskDir, { recursive: true })
+		const filePath = path.join(taskDir, "api_conversation_history.json")
+		await fs.writeFile(filePath, "<<<corrupt data>>>", "utf8")
+
+		const result = await readApiMessages({
+			taskId,
+			globalStoragePath: tmpBaseDir,
+		})
+
+		expect(result).toEqual([])
+	})
+
+	it("returns empty array when claude_messages.json fallback contains invalid JSON", async () => {
+		const taskId = "task-corrupt-fallback"
+		const taskDir = path.join(tmpBaseDir, "tasks", taskId)
+		await fs.mkdir(taskDir, { recursive: true })
+
+		// Only write the old fallback file (claude_messages.json), NOT the new one
+		const oldPath = path.join(taskDir, "claude_messages.json")
+		await fs.writeFile(oldPath, "not json at all {[!", "utf8")
+
+		const result = await readApiMessages({
+			taskId,
+			globalStoragePath: tmpBaseDir,
+		})
+
+		expect(result).toEqual([])
+
+		// The corrupted fallback file should NOT be deleted
+		const stillExists = await fs
+			.access(oldPath)
+			.then(() => true)
+			.catch(() => false)
+		expect(stillExists).toBe(true)
+	})
+
+	it("returns [] when file contains valid JSON that is not an array", async () => {
+		const taskId = "task-non-array-api"
+		const taskDir = path.join(tmpBaseDir, "tasks", taskId)
+		await fs.mkdir(taskDir, { recursive: true })
+		const filePath = path.join(taskDir, "api_conversation_history.json")
+		await fs.writeFile(filePath, JSON.stringify("hello"), "utf8")
+
+		const result = await readApiMessages({
+			taskId,
+			globalStoragePath: tmpBaseDir,
+		})
+
+		expect(result).toEqual([])
+	})
+
+	it("returns [] when fallback file contains valid JSON that is not an array", async () => {
+		const taskId = "task-non-array-fallback"
+		const taskDir = path.join(tmpBaseDir, "tasks", taskId)
+		await fs.mkdir(taskDir, { recursive: true })
+
+		// Only write the old fallback file, NOT the new one
+		const oldPath = path.join(taskDir, "claude_messages.json")
+		await fs.writeFile(oldPath, JSON.stringify({ key: "value" }), "utf8")
+
+		const result = await readApiMessages({
+			taskId,
+			globalStoragePath: tmpBaseDir,
+		})
+
+		expect(result).toEqual([])
+	})
+})

src/core/task-persistence/__tests__/taskMessages.spec.ts

@@ -12,7 +12,7 @@ vi.mock("../../../utils/safeWriteJson", () => ({
 }))
 
 // Import after mocks
-import { saveTaskMessages } from "../taskMessages"
+import { saveTaskMessages, readTaskMessages } from "../taskMessages"
 
 let tmpBaseDir: string
 
@@ -66,3 +66,36 @@ describe("taskMessages.saveTaskMessages", () => {
 		expect(persisted).toEqual(messages)
 	})
 })
+
+describe("taskMessages.readTaskMessages", () => {
+	it("returns empty array when file contains invalid JSON", async () => {
+		const taskId = "task-corrupt-json"
+		// Manually create the task directory and write corrupted JSON
+		const taskDir = path.join(tmpBaseDir, "tasks", taskId)
+		await fs.mkdir(taskDir, { recursive: true })
+		const filePath = path.join(taskDir, "ui_messages.json")
+		await fs.writeFile(filePath, "{not valid json!!!", "utf8")
+
+		const result = await readTaskMessages({
+			taskId,
+			globalStoragePath: tmpBaseDir,
+		})
+
+		expect(result).toEqual([])
+	})
+
+	it("returns [] when file contains valid JSON that is not an array", async () => {
+		const taskId = "task-non-array-json"
+		const taskDir = path.join(tmpBaseDir, "tasks", taskId)
+		await fs.mkdir(taskDir, { recursive: true })
+		const filePath = path.join(taskDir, "ui_messages.json")
+		await fs.writeFile(filePath, JSON.stringify("hello"), "utf8")
+
+		const result = await readTaskMessages({
+			taskId,
+			globalStoragePath: tmpBaseDir,
+		})
+
+		expect(result).toEqual([])
+	})
+})

src/core/task-persistence/apiMessages.ts

@@ -51,17 +51,23 @@ export async function readApiMessages({
 		const fileContent = await fs.readFile(filePath, "utf8")
 		try {
 			const parsedData = JSON.parse(fileContent)
-			if (Array.isArray(parsedData) && parsedData.length === 0) {
+			if (!Array.isArray(parsedData)) {
+				console.warn(
+					`[readApiMessages] Parsed data is not an array (got ${typeof parsedData}), returning empty. TaskId: ${taskId}, Path: ${filePath}`,
+				)
+				return []
+			}
+			if (parsedData.length === 0) {
 				console.error(
 					`[Roo-Debug] readApiMessages: Found API conversation history file, but it's empty (parsed as []). TaskId: ${taskId}, Path: ${filePath}`,
 				)
 			}
 			return parsedData
 		} catch (error) {
-			console.error(
-				`[Roo-Debug] readApiMessages: Error parsing API conversation history file. TaskId: ${taskId}, Path: ${filePath}, Error: ${error}`,
+			console.warn(
+				`[readApiMessages] Error parsing API conversation history file, returning empty. TaskId: ${taskId}, Path: ${filePath}, Error: ${error}`,
 			)
-			throw error
+			return []
 		}
 	} else {
 		const oldPath = path.join(taskDir, "claude_messages.json")
@@ -70,19 +76,25 @@ export async function readApiMessages({
 			const fileContent = await fs.readFile(oldPath, "utf8")
 			try {
 				const parsedData = JSON.parse(fileContent)
-				if (Array.isArray(parsedData) && parsedData.length === 0) {
+				if (!Array.isArray(parsedData)) {
+					console.warn(
+						`[readApiMessages] Parsed OLD data is not an array (got ${typeof parsedData}), returning empty. TaskId: ${taskId}, Path: ${oldPath}`,
+					)
+					return []
+				}
+				if (parsedData.length === 0) {
 					console.error(
 						`[Roo-Debug] readApiMessages: Found OLD API conversation history file (claude_messages.json), but it's empty (parsed as []). TaskId: ${taskId}, Path: ${oldPath}`,
 					)
 				}
 				await fs.unlink(oldPath)
 				return parsedData
 			} catch (error) {
-				console.error(
-					`[Roo-Debug] readApiMessages: Error parsing OLD API conversation history file (claude_messages.json). TaskId: ${taskId}, Path: ${oldPath}, Error: ${error}`,
+				console.warn(
+					`[readApiMessages] Error parsing OLD API conversation history file (claude_messages.json), returning empty. TaskId: ${taskId}, Path: ${oldPath}, Error: ${error}`,
 				)
-				// DO NOT unlink oldPath if parsing failed, throw error instead.
-				throw error
+				// DO NOT unlink oldPath if parsing failed.
+				return []
 			}
 		}
 	}

src/core/task-persistence/taskMessages.ts

@@ -23,7 +23,21 @@ export async function readTaskMessages({
 	const fileExists = await fileExistsAtPath(filePath)
 
 	if (fileExists) {
-		return JSON.parse(await fs.readFile(filePath, "utf8"))
+		try {
+			const parsedData = JSON.parse(await fs.readFile(filePath, "utf8"))
+			if (!Array.isArray(parsedData)) {
+				console.warn(
+					`[readTaskMessages] Parsed data is not an array (got ${typeof parsedData}), returning empty. TaskId: ${taskId}, Path: ${filePath}`,
+				)
+				return []
+			}
+			return parsedData
+		} catch (error) {
+			console.warn(
+				`[readTaskMessages] Failed to parse ${filePath} for task ${taskId}, returning empty: ${error instanceof Error ? error.message : String(error)}`,
+			)
+			return []
+		}
 	}
 
 	return []

src/core/task/Task.ts

@@ -1203,10 +1203,10 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 	 * tools execute (added in recursivelyMakeClineRequests after streaming completes).
 	 * So we usually only need to flush the pending user message with tool_results.
 	 */
-	public async flushPendingToolResultsToHistory(): Promise<void> {
+	public async flushPendingToolResultsToHistory(): Promise<boolean> {
 		// Only flush if there's actually pending content to save
 		if (this.userMessageContent.length === 0) {
-			return
+			return true
 		}
 
 		// CRITICAL: Wait for the assistant message to be saved to API history first.
@@ -1236,7 +1236,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 
 		// If task was aborted while waiting, don't flush
 		if (this.abort) {
-			return
+			return false
 		}
 
 		// Save the user message with tool_result blocks
@@ -1253,25 +1253,58 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 		const userMessageWithTs = { ...validatedMessage, ts: Date.now() }
 		this.apiConversationHistory.push(userMessageWithTs as ApiMessage)
 
-		await this.saveApiConversationHistory()
+		const saved = await this.saveApiConversationHistory()
+
+		if (saved) {
+			// Clear the pending content since it's now saved
+			this.userMessageContent = []
+		} else {
+			console.warn(
+				`[Task#${this.taskId}] flushPendingToolResultsToHistory: save failed, retaining pending tool results in memory`,
+			)
+		}
 
-		// Clear the pending content since it's now saved
-		this.userMessageContent = []
+		return saved
 	}
 
-	private async saveApiConversationHistory() {
+	private async saveApiConversationHistory(): Promise<boolean> {
 		try {
 			await saveApiMessages({
-				messages: this.apiConversationHistory,
+				messages: structuredClone(this.apiConversationHistory),
 				taskId: this.taskId,
 				globalStoragePath: this.globalStoragePath,
 			})
+			return true
 		} catch (error) {
-			// In the off chance this fails, we don't want to stop the task.
 			console.error("Failed to save API conversation history:", error)
+			return false
 		}
 	}
 
+	/**
+	 * Public wrapper to retry saving the API conversation history.
+	 * Uses exponential backoff: up to 3 attempts with delays of 100 ms, 500 ms, 1500 ms.
+	 * Used by delegation flow when flushPendingToolResultsToHistory reports failure.
+	 */
+	public async retrySaveApiConversationHistory(): Promise<boolean> {
+		const delays = [100, 500, 1500]
+
+		for (let attempt = 0; attempt < delays.length; attempt++) {
+			await new Promise<void>((resolve) => setTimeout(resolve, delays[attempt]))
+			console.warn(
+				`[Task#${this.taskId}] retrySaveApiConversationHistory: retry attempt ${attempt + 1}/${delays.length}`,
+			)
+
+			const success = await this.saveApiConversationHistory()
+
+			if (success) {
+				return true
+			}
+		}
+
+		return false
+	}
+
 	// Cline Messages
 
 	private async getSavedClineMessages(): Promise<ClineMessage[]> {
@@ -1333,10 +1366,10 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 		}
 	}
 
-	private async saveClineMessages() {
+	private async saveClineMessages(): Promise<boolean> {
 		try {
 			await saveTaskMessages({
-				messages: this.clineMessages,
+				messages: structuredClone(this.clineMessages),
 				taskId: this.taskId,
 				globalStoragePath: this.globalStoragePath,
 			})
@@ -1366,8 +1399,10 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 			this.debouncedEmitTokenUsage(tokenUsage, this.toolUsage)
 
 			await this.providerRef.deref()?.updateTaskHistory(historyItem)
+			return true
 		} catch (error) {
 			console.error("Failed to save Roo messages:", error)
+			return false
 		}
 	}