On this REL1_39 backport, CI is failing (client console, repo console) with lots of deprecation warnings, and in the repo case, one fatal error:
PHP Fatal error: During inheritance of Iterator: Uncaught Return type of Wikibase\Repo\IO\LineReader::current() should either be compatible with Iterator::current(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice /workspace/src/extensions/Wikibase/repo/includes/IO/LineReader.php:101 /workspace/src/extensions/Wikibase/repo/includes/IO/LineReader.php:16 /workspace/src/includes/AutoLoader.php:244 /workspace/src/extensions/Wikibase/repo/tests/phpunit/includes/IO/EntityIdReaderTest.php:32 /workspace/src/extensions/Wikibase/repo/tests/phpunit/includes/IO/EntityIdReaderTest.php:54 in /workspace/src/extensions/Wikibase/repo/includes/IO/LineReader.php on line 16
Also, this branch is probably also affected by T385175.
MediaWiki 1.39 is an LTS release that’s supposed to be supported until November 2025, so it would be nice if we could fix this. That said, given how many different deprecation warnings there are, I’m not sure how easy this will be. (Some of the fixes can probably be found at T319219.)