Change 631442 had a related patch set uploaded (by Ammarpad; owner: Ammarpad):
[mediawiki/core@master] Add WatchlistExpiry support to ApiBlock

https://gerrit.wikimedia.org/r/631442

Change 631442 merged by jenkins-bot:
[mediawiki/core@master] Add WatchlistExpiry support to ApiBlock

https://gerrit.wikimedia.org/r/631442

When using API:Block I can now pass a watchlistexpiry parameter (alongside the existing watchuser parameter). This watches the target of the block's User and User_talk page for the time specified.

It returns the watch expiry in the API response. For example, performing this request (watch expiry highlighted):

{
    "block": {
        "user": "Drwpb",
        "userID": 16190,
        "expiry": "2020-11-06T15:12:20Z",
        "id": 15958,
        "reason": "sjdfklsdjl",
        "nocreate": "",
        "noemail": "",
        "watchuser": "",
        "watchlistexpiry": "2020-10-20T15:12:20Z", <---
        "pagerestrictions": [],
        "namespacerestrictions": null
    }
}

If I pass an infinite value for watchlistexpiry, it will update the User/User_talk watches to be permanent, and return a null value for watch expiry. E.g. this request:

{
    "block": {
        ...
        "watchuser": "",
        "watchlistexpiry": null,
	...
    }
}

If I pass watchuser but not watchlistexpiry (for example, this request):

• if User/User_talk pages are not already watched, it will watch them permanently
• if User/User_talk pages are already watched, it will not change the watch or the expiry

Note that if I don't pass watchlistexpiry the API response will not include the watch expiry (even if the User/User_talk pages are already temporarily watched).

Also note that not passing watchuser will not unwatch a page that is already watched. This behaviour pre-dates this change.

The normal validation rules for watchlist expiries apply. For example, if you enter a value greater than 6 months, you get a warning (below) and the User/User_talk pages are watched for 6 months instead.

{
    "warnings": {
        "block": {
            "*": "Given value \"20 months\" for parameter \"watchlistexpiry\" exceeds the maximum of \"6 months\". Using maximum instead."
        }
    },
    ...
}

I briefly tested API:Block with watchlist expiry disabled. As far as I am aware, it works the same as it did before this change.

@ifried I notice your staff account has Administrator rights on testwiki. This means you should be able to test this on testwiki when it goes to production. E.g. https://test.wikipedia.org/wiki/Special:ApiSandbox#action=block&format=json&user=Drwpb&watchuser=1&watchlistexpiry=2%20weeks

Test Environments:

• https://en.wikipedia.beta.wmflabs.org MediaWiki 1.36.0-alpha (49b7f80) 2020-10-06T10:09:20
• local vagrant MediaWiki 1.36.0-alpha (3e49177) (for testing with watchlist expiry disabled)