doc.wikimedia.org is hosted on doc1002.eqiad.wmnet which has Buster. It gets PHP from Debian and thus runs PHP 7.3.

We might be able to upgrade it to PHP 7.4 by using the same package used by MediaWiki php7.4 from buster-wikimedia/component/php74.

A non exhaustive list of things to check for compatibility

• integration/docroot which holds the code powering doc.wikimedia.org as well as integration.wikimedia.org (which is on Buster machine contint2001.wikimedia.org)
• Doxygen search example: https://doc.wikimedia.org/mediawiki-core/master/php/search.php?query=ParserOutput
• OOUI has some PHP demos as well

And anything else that might be running PHP scripts.

@hashar Do we have enabled and access to some kind of error_log for the doc1002 php-fpm instance where we might find about PHP Deprecated warnings etc? That might help increase confidence that nothing will break and possibly identify additional things that use PHP.

To my knowledge, though, your list is complete. When I last tried to make a complete list, I saved it at https://wikitech.wikimedia.org/wiki/Doc.wikimedia.org and that seems to match.

In T322357#8468528, @Krinkle wrote:

@hashar Do we have enabled and access to some kind of error_log for the doc1002 php-fpm instance where we might find about PHP Deprecated warnings etc? That might help increase confidence that nothing will break and possibly identify additional things that use PHP.

I have absolutely no idea whether they are captured anywhere. At least I have never actively looked at the error logs on the hosts themselves and I don't think I ever encountered doc1002 host via our ELK stack. A search there yields no result for doc1002 so I guess the logging pipeline is not setup.

For PHP error_log, we use the stock config files from Debian:

hashar@doc1002:/etc/php/7.3/fpm$ grep -PR ^error_
php-fpm.conf:error_log = /var/log/php7.3-fpm.log
php.ini:error_reporting = E_ALL & ~E_DEPRECATED & ~E_STRICT

To my knowledge, though, your list is complete. When I last tried to make a complete list, I saved it at https://wikitech.wikimedia.org/wiki/Doc.wikimedia.org and that seems to match.

That is so helpful, thank you for that.

Is there any update on when this is going to be fixed? Not having this documentation severly hinders extension development for those not familiar with OOUI and the documentation on mw.org isn't really exhaustive.

In T322357#8468528, @Krinkle wrote:

@hashar Do we have enabled and access to some kind of error_log for the doc1002 php-fpm instance where we might find about PHP Deprecated warnings etc? That might help increase confidence that nothing will break and possibly identify additional things that use PHP.

There is a task to drop the logs to logstash indeed: T325245

In T322357#8603557, @OriginalAuthority wrote:

Is there any update on when this is going to be fixed? Not having this documentation severly hinders extension development for those not familiar with OOUI and the documentation on mw.org isn't really exhaustive.

The root cause is the PHP version comes from the hosts Debian system and upgrading the OS tends to be a bit painful (we got to create a new VM, provision it with a new OS which often requires adjustments to the provisioning manifest, we gotta move data around ...). Those are not necessarily hard, but they come up on top of a long list of things we have to do, thus the progress is rather slow.

Change 901149 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[oojs/ui@master] Revert "[BREAKING CHANGE] Raise claimed PHP need from 7.2+ to 7.4+"

https://gerrit.wikimedia.org/r/901149

Change 901612 had a related patch set uploaded (by Hashar; author: Hashar):

[operations/puppet@production] doc: upgrade php from 7.3 to 7.4

https://gerrit.wikimedia.org/r/901612