Reinstalling an application creates a ghost of its schedules

Start with the scheduler configuration in devvit.json, the route shown in index.ts, and the scheduler.listJobs() result. Reproduce the install, uninstall, and reinstall sequence, then trace which scheduled jobs remain and how the Redis-stored widget ID is used. Done means uninstalling removes prior schedules so reinstalling leaves only the current job and does not create duplicate widget updates.

Reddit does not properly clean up apps when they are uninstalled.

You can reproduce this by adding a schedule in your devvit.json. like so:

"scheduler": {
	"tasks": {
		"daily-guides": {
			"endpoint": "/internal/scheduler/daily-guides",
			"cron": "* * * * *"
		}
	}
},

Then, configure a route to handle it:

// index.ts.
router.post("/internal/scheduler/daily-guides", scheduleFunction);

// Maybe in another file...
import { context, reddit, redis } from "@devvit/web/server";

export async function scheduleFunction() {
	const widgetId = await redis.get('schedule-key');

	if (!widgetId) {
		console.info("Widget not found. Creating one.");

		const widget = await reddit.addWidget({
			subreddit: context.subredditName,
			type: "textarea",
			shortName: "Countdown",
			text: "test",
		});

		await redis.set('schedule-key', widget.id);
		return;
	}

	await reddit.updateWidget({
		subreddit: context.subredditName,
		type: "textarea",
		id: widgetId,
		shortName: "Countdown",
		text: "test",
	});
}

Then:

1. Install the app to a subreddit
2. Uninstall it after several minutes
3. Install the app to the aforementioned subreddit

After a few minutes after step 3, you'll have a mod log like this:

It looks like the first scheduled has returned and it is updating the widget from the id stored in Redis somehow. It shouldn't know that it is still there. Then, it starts a new schedule from installation, creating a widget since it doesn't know anything about the subreddit which is expected behaviour, stores the widget id in Redis, and proceeds to edit it. This leads to 2 widgets.

If you run await scheduler.listJobs();, only 1 job would be listed–the job you started your application with to log that in the first place–not 2. The other schedule is now a ghost–you cannot find it, you cannot stop it, you cannot uninstall your application as a workaround as demonstrated above... it's totally broken.

I'd appreciate if a lurking administrator can resolve my prior schedules (my application is in the above screenshot)!