@gengh What is the main goal of this and why is Essential?

@DSantamaria The main goal is to avoid causing failures in client wikis.
Client and server code are together in the same repo, however if we perform server operations (fetch ZObjects) from client or client-called code, it will generate unexpected and potentially very dangerous breakages.
This work is Essential and high priority.

This didn't get done in Q1; moving back to Triage.

Change #1248016 had a related patch set uploaded (by Genoveva Galarza; author: Genoveva Galarza):

[mediawiki/extensions/WikiLambda@master] [WIP] Remove risk to make local fetches when producing exceptions in clients

https://gerrit.wikimedia.org/r/1248016

Change #1248016 merged by jenkins-bot:

[mediawiki/extensions/WikiLambda@master] Remove risk to make local fetches when producing exceptions in clients

https://gerrit.wikimedia.org/r/1248016

We removed from WikifunctionCallException as part of abstract exception work, but we still need to make sure that ZObjectFactory::create is not called from clients wikis (abstract or other)
Moving this back to ready and marking it as fixit (no emergency work, but would be good to have some dedicated eyes making this check soon)

Detect those places in the client classes (WikifunctionsClientRequestJob, WikifunctionsPFHandler, etc) where we are doing this

Doesn't look like this is happening anywhere (anymore?)

But the caveat is that the safety is per-caller, not structural, as in ZObjectStore itself has no guard, it's just safe right now because the current callers have a check