Fix scoreboard update after rejudging.

[meisterT]

Previous buggy flow was something like:

• fetch all submissions that for this team/contest/problem combination
• that are valid
• and have a valid judging

The idea of

domjudge/webapp/src/Service/ScoreboardService.php

Line 240 in 95df1de

->leftJoin('s.judgings', 'j', Join::WITH, 'j.valid = 1')

was that this would filter the OneToMany collection down to only valid judgings. This is also what happens on the database side.

However, on the doctrine side, the entity manager keeps a cache, and if the submission is already in the cache with the full collection of valid and invalid judgings, it will only merged with new data from the database query, no data (i.e. no judgings) will magically disappear.

In order to fix this, we explicitly filter on the PHP side. An alternative would be to add a new OneToMany mapping with a where on it and use that.

Fixes #2883

[vmcj]

Why is it so hard (or expensive) to fix this in the DB side? I miss that comment currently.

[meisterT]

In order to fix this, we explicitly filter on the PHP side. An alternative would be to add a new OneToMany mapping with a where on it and use that.

I am not aware of any fix on the DB side. We could decide to switch off doctrine or disable any entity caching which would cost performance.

In case you are refering to what I wrote in the commit description:

In order to fix this, we explicitly filter on the PHP side. An alternative would be to add a new OneToMany mapping with a where on it and use that.

The two options are relatively equal. I picked filtering on the PHP side since 99% of submissions have 1 judging, so it is very cheap to do so. The other solution would not change the DB but allow us to to do an implicit DB query but it would require a migration.

[nickygerritsen]

Suggested change

	foreach ($this->judgings as $j) {
	if ($j->getValid()) {
	return $j;
	}
	}
	return null;
	return $this->judgings->findFirst(fn(Judging $j) => $j->getValid());

maybe?