fix: don't advance lastDate() for ticks skipped by waitForCompletion

src/job.ts

@@ -127,7 +127,6 @@ export class CronJob<OC extends CronOnCompleteCommand | null = null, C = null> {
 		this.addCallback(this._fnWrap(onTick));
 
 		if (runOnInit) {
-			this.lastExecution = new Date();
 			void this.fireOnTick();
 		}
 
@@ -245,6 +244,10 @@ export class CronJob<OC extends CronOnCompleteCommand | null = null, C = null> {
 		// skip job if previous callback is still running
 		if (this.waitForCompletion && this._isCallbackRunning) return;
 
+		// record the moment the callback actually executes, so that lastDate()
+		// reflects the last real execution rather than the last tick check
+		// (ticks skipped above must not advance it). See #1048.
+		this.lastExecution = new Date();
 		this._isCallbackRunning = true;
 
 		// handle errors in synchronous and asynchronous callbacks
@@ -334,8 +337,6 @@ export class CronJob<OC extends CronOnCompleteCommand | null = null, C = null> {
 				setCronTimeout(timeout);
 			} else {
 				// we have arrived at the correct point in time.
-				this.lastExecution = new Date();
-
 				this._isActive = false;
 
 				// start before calling back so the callbacks have the ability to stop the cron job
@@ -364,7 +365,6 @@ export class CronJob<OC extends CronOnCompleteCommand | null = null, C = null> {
 				// execute immediately if within threshold
 				console.warn(`${message}. Executing immediately.`);
 
-				this.lastExecution = new Date();
 				void this.fireOnTick();
 			} else {
 				// skip job if beyond threshold

tests/cron.test.ts

@@ -1436,6 +1436,45 @@ describe('cron', () => {
 			expect(job.isCallbackRunning).toBe(false);
 			expect(job.isActive).toBe(false);
 		});
+
+		it('should not advance lastDate() for ticks skipped due to waitForCompletion (#1048)', async () => {
+			const clock = sinon.useFakeTimers();
+
+			const job = new CronJob(
+				'* * * * * *',
+				async () => {
+					await new Promise<void>(resolve => {
+						setTimeout(resolve, 1500);
+					});
+				},
+				null,
+				true,
+				null,
+				null,
+				false,
+				null,
+				false,
+				true // waitForCompletion: true
+			);
+
+			// first execution starts at 1000ms
+			await clock.tickAsync(1000);
+			expect(job.isCallbackRunning).toBe(true);
+			expect(job.lastDate()?.getTime()).toBe(1000);
+
+			// the tick at 2000ms is skipped because the callback is still
+			// running, so lastDate() must still reflect the 1000ms execution.
+			await clock.tickAsync(1000);
+			expect(job.isCallbackRunning).toBe(true);
+			expect(job.lastDate()?.getTime()).toBe(1000);
+
+			// first callback completes at 2500ms, next execution starts at 3000ms
+			await clock.tickAsync(1000);
+			expect(job.isCallbackRunning).toBe(true);
+			expect(job.lastDate()?.getTime()).toBe(3000);
+
+			job.stop();
+		});
 	});
 
 	describe('Daylight Saving Time', () => {