Note that some providers would meet the requirements for auto fixing, but cannot be made static because they are an override of a non-static method defined in a parent class (e.g. HookRunnerTestBase).

Using Late Static Binding is a solution for those cases, and what I used in 904876.

Change 921431 had a related patch set uploaded (by Umherirrender; author: Umherirrender):

[mediawiki/tools/codesniffer@master] Test for static PHPUnit data providers

https://gerrit.wikimedia.org/r/921431

In T333745#8866143, @gerritbot wrote:

Change 921431 had a related patch set uploaded (by Umherirrender; author: Umherirrender):

[mediawiki/tools/codesniffer@master] Test for static PHPUnit data providers

https://gerrit.wikimedia.org/r/921431

Just some stats: For wmf deployed extensions/skins the sniff found 2534 "issues" in 93 extensions/skins of them, where 459 issues in 45 extensions/skins calls $this in the provider and the rest of 2075 are eligible for easy fix (but needs verify by CI).

Is there a way to see if this actually saves us time, and how much?

In T333745#8870633, @thiemowmde wrote:

Is there a way to see if this actually saves us time, and how much?

I see no effect on CI. The start-up time of phpunit should/could be a small fraction faster (for example when using --filter), maybe the memory footprint of the full run is a bit lower as the objects gets created later and can be destroyed earlier (when mock builder get moved out of provider).

But the most benefit/need is, that the non-static provider are deprecated in PHPunit 10 - https://github.com/sebastianbergmann/phpunit/commit/9caafe2d49b33a21f87db248a8ad6ca7c7bdac09 - so there is already some need to do this in the future.

Change 921431 abandoned by Umherirrender:

[mediawiki/tools/codesniffer@master] Test for non-static PHPUnit data providers (with autofix)

Reason:

The detection and the autofix have false positives, so this may nothing for automated tasks or autofix

https://gerrit.wikimedia.org/r/921431