Fix Google Calendar sync race condition and recurring completion date bug

docs/releases/unreleased.md

@@ -23,3 +23,8 @@ Example:
 ```
 
 -->
+
+## Fixed
+
+- (#1764) Fixed Google Calendar sync using stale task metadata after rapid task updates, and fixed late recurring completions/skips recording the completion day instead of the scheduled occurrence date.
+  - Thanks to @martin-forge for the PR and to @jpmoo for reporting the recurring completion issues.

src/main.ts

@@ -49,7 +49,6 @@ import { ViewStateManager } from "./services/ViewStateManager";
 import { DragDropManager } from "./utils/DragDropManager";
 import {
 	formatDateForStorage,
-	createUTCDateFromLocalCalendarDate,
 	parseDateToLocal,
 	getTodayLocal,
 } from "./utils/dateUtils";
@@ -1060,17 +1059,8 @@ export default class TaskNotesPlugin extends Plugin {
 	 */
 	async toggleRecurringTaskComplete(task: TaskInfo, date?: Date): Promise<TaskInfo> {
 		try {
-			// Let TaskService handle the date logic (defaults to local today, not selectedDate)
-			const updatedTask = await this.taskService.toggleRecurringTaskComplete(task, date);
-
-			// For notification, determine the actual completion date from the task
-			// Use local today if no explicit date provided
-			const targetDate =
-				date ||
-				(() => {
-					const todayLocal = getTodayLocal();
-					return createUTCDateFromLocalCalendarDate(todayLocal);
-				})();
+			const targetDate = await this.taskService.resolveRecurringTaskActionDate(task, date);
+			const updatedTask = await this.taskService.toggleRecurringTaskComplete(task, targetDate);
 
 			const dateStr = formatDateForStorage(targetDate);
 			const wasCompleted = updatedTask.complete_instances?.includes(dateStr);

src/services/TaskCalendarSyncService.ts

@@ -35,6 +35,9 @@ export class TaskCalendarSyncService {
 	/** Track previous task state for detecting recurrence removal */
 	private previousTaskState: Map<string, TaskInfo> = new Map();
 
+	/** Store the latest explicitly passed task object during debounce to avoid cache race conditions */
+	private pendingTasks: Map<string, TaskInfo> = new Map();
+
 	constructor(plugin: TaskNotesPlugin, googleCalendarService: GoogleCalendarService) {
 		this.plugin = plugin;
 		this.googleCalendarService = googleCalendarService;
@@ -49,6 +52,7 @@ export class TaskCalendarSyncService {
 		}
 		this.pendingSyncs.clear();
 		this.previousTaskState.clear();
+		this.pendingTasks.clear();
 	}
 
 	/**
@@ -765,6 +769,9 @@ export class TaskCalendarSyncService {
 			clearTimeout(existingTimer);
 		}
 
+		// Store the authoritative task state passed to us so we don't rely on the async metadata cache
+		this.pendingTasks.set(taskPath, task);
+
 		// Return a promise that resolves when the debounced sync completes
 		return new Promise((resolve, reject) => {
 			const timer = setTimeout(async () => {
@@ -776,8 +783,13 @@ export class TaskCalendarSyncService {
 					await inFlight.catch(() => {}); // Ignore errors from previous sync
 				}
 
-				// Re-fetch the task to get the latest state after debounce
-				const freshTask = await this.plugin.cacheManager.getTaskInfo(taskPath);
+				// Use the latest task data that was passed to us explicitly
+				const latestTask = this.pendingTasks.get(taskPath);
+				this.pendingTasks.delete(taskPath);
+
+				// Fallback to cache only if the pending task is missing
+				const freshTask = latestTask || await this.plugin.cacheManager.getTaskInfo(taskPath);
+
 				if (!freshTask) {
 					resolve();
 					return;

src/services/TaskService.ts

@@ -39,10 +39,12 @@ import {
 import { getProjectDisplayName } from "../utils/linkUtils";
 import {
 	formatDateForStorage,
+	getDatePart,
 	getCurrentDateString,
 	getCurrentTimestamp,
 	getTodayLocal,
 	createUTCDateFromLocalCalendarDate,
+	parseDateToUTC,
 } from "../utils/dateUtils";
 import { format } from "date-fns";
 import { processFolderTemplate, TaskTemplateData } from "../utils/folderTemplateProcessor";
@@ -1275,6 +1277,28 @@ export class TaskService {
 	/**
 	 * Toggle completion status for recurring tasks on a specific date
 	 */
+	async resolveRecurringTaskActionDate(task: TaskInfo, date?: Date): Promise<Date> {
+		if (date) {
+			return date;
+		}
+
+		const freshTask = (await this.plugin.cacheManager.getTaskInfo(task.path)) || task;
+		return this.getRecurringTaskActionDate(freshTask);
+	}
+
+	private getRecurringTaskActionDate(task: TaskInfo, date?: Date): Date {
+		if (date) {
+			return date;
+		}
+
+		if (task.recurrence_anchor !== "completion" && task.scheduled) {
+			return parseDateToUTC(getDatePart(task.scheduled));
+		}
+
+		const todayLocal = getTodayLocal();
+		return createUTCDateFromLocalCalendarDate(todayLocal);
+	}
+
 	async toggleRecurringTaskComplete(task: TaskInfo, date?: Date): Promise<TaskInfo> {
 		const file = this.plugin.app.vault.getAbstractFileByPath(task.path);
 		if (!(file instanceof TFile)) {
@@ -1288,14 +1312,7 @@ export class TaskService {
 			throw new Error("Task is not recurring");
 		}
 
-		// Default to local today instead of selectedDate for recurring task completion
-		// This ensures completion is recorded for user's actual calendar day unless explicitly overridden
-		const targetDate =
-			date ||
-			(() => {
-				const todayLocal = getTodayLocal();
-				return createUTCDateFromLocalCalendarDate(todayLocal);
-			})();
+		const targetDate = this.getRecurringTaskActionDate(freshTask, date);
 		const dateStr = formatDateForStorage(targetDate);
 
 		// Check current completion status for this date using fresh data
@@ -1514,13 +1531,7 @@ export class TaskService {
 			throw new Error("Task is not recurring");
 		}
 
-		// Default to local today
-		const targetDate =
-			date ||
-			(() => {
-				const todayLocal = getTodayLocal();
-				return createUTCDateFromLocalCalendarDate(todayLocal);
-			})();
+		const targetDate = this.getRecurringTaskActionDate(freshTask, date);
 		const dateStr = formatDateForStorage(targetDate);
 
 		// Check current skip status for this date

tests/services/TaskCalendarSyncService.test.ts

@@ -0,0 +1,81 @@
+import { TaskCalendarSyncService } from "../../src/services/TaskCalendarSyncService";
+import { TaskInfo } from "../../src/types";
+
+describe("TaskCalendarSyncService", () => {
+    let syncService: any;
+    let mockPlugin: any;
+    let mockGoogleCalendarService: any;
+
+    beforeEach(() => {
+        jest.useFakeTimers();
+
+        mockPlugin = {
+            settings: {
+                googleCalendarExport: {
+                    syncOnTaskUpdate: true,
+                    targetCalendarId: "test-calendar",
+                }
+            },
+            cacheManager: {
+                getTaskInfo: jest.fn()
+            },
+            statusManager: {
+                getStatusConfig: jest.fn().mockReturnValue({ label: "Todo" })
+            },
+            priorityManager: {
+                getPriorityConfig: jest.fn().mockReturnValue({ label: "High" })
+            },
+            i18n: {
+                translate: jest.fn().mockReturnValue("Untitled Task")
+            }
+        };
+
+        mockGoogleCalendarService = {
+            updateEvent: jest.fn().mockResolvedValue({}),
+            createEvent: jest.fn().mockResolvedValue({ id: "test-id" })
+        };
+
+        syncService = new TaskCalendarSyncService(mockPlugin, mockGoogleCalendarService);
+
+        // Mock internal methods to avoid testing downstream serialization logic which might be complex
+        syncService.executeTaskUpdate = jest.fn().mockResolvedValue(undefined);
+    });
+
+    afterEach(() => {
+        jest.useRealTimers();
+    });
+
+    it("should use the most recently passed task explicitly, avoiding stale cacheManager payloads during debounce", async () => {
+        const taskPath = "test/path.md";
+
+        const firstPayload: TaskInfo = {
+            path: taskPath,
+            title: "Task Title",
+            scheduled: "2026-04-04"
+        };
+
+        const secondPayload: TaskInfo = {
+            path: taskPath,
+            title: "Task Title",
+            scheduled: "2026-04-06" // Agent updated it to April 6
+        };
+
+        // Pretend the metadataCache hasn't caught up and still returns the stale task
+        mockPlugin.cacheManager.getTaskInfo.mockResolvedValue(firstPayload);
+
+        // Act: trigger sync twice rapidly to simulate MCP updates or user typing
+        syncService.updateTaskInCalendar(firstPayload);
+        syncService.updateTaskInCalendar(secondPayload);
+
+        // Fast-forward past the 500ms debounce
+        jest.advanceTimersByTime(500);
+
+        // Flush the microtask queue so the async debounce handler completes
+        await Promise.resolve();
+        await Promise.resolve();
+
+        // Assert: It should execute only once, and pass the explicit secondPayload, not the stale cache!
+        expect(syncService.executeTaskUpdate).toHaveBeenCalledTimes(1);
+        expect(syncService.executeTaskUpdate).toHaveBeenCalledWith(secondPayload);
+    });
+});