Special:Version is using is_file() to check if $wgGitBin is set to a valid git binary path, but that produces a warning if there's an open_basedir restriction in effect. This only happens when there are extensions installed downloaded from git.
We should probably use [[https://www.mediawiki.org/wiki/Manual:Coding_conventions/PHP#Error_handling | error handling]] to prevent that warning from popping up.
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Steps to reproduce:
- Download an extension from git.
* Example: go to the extensions directory and use `git clone https://gerrit.wikimedia.org/r/p/mediawiki/extensions/UserMerge`
- Load the extension in LocalSettings.php.
* Example: `wfLoadExtension( 'UserMerge' );`
- Be sure php.ini has `open_basedir` set to MediaWiki install directory, and probably a temp directory like /tmp
- Go to Special:Version and it should display the warning (if your `error_reporting` configuration is not hiding it).
NOTE: The warning will be displayed only once, then the information will be cached. To display the warning again you should clear the object cache. In case the object cache is in database, simply issue a `truncate table objectcache;` on the database and reload the Special:Version page again to see the warning.
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**Original Version**: 1.23.5
**Latest version reproduced**: 1.29-rc0
**URL**: https://www.mediawiki.org/wiki/Thread:Project:Support_desk/Odd_occurrence_when_viewing_Special:Version