Using PHP 7.2, given you have the following set up:

# In mediawiki.inc
​​$enable_compatibility_view = true;

and in Mediawiki Administration you have checked the "full screen" checkbox,
When you try to Edit any page, you will have the following Fatal error:

[93a6185a] /plugins/mediawiki/wiki/mediawiki-heavy-summer/index.php?title=Main_Page&action=edit Exception from line 222 of /usr/share/mediawiki-tuleap-123/includes/Hooks.php: Detected bug in an extension! Hook WikiEditorHooks::editPageShowEditFormInitial has invalid call signature; Parameter 1 to WikiEditorHooks::editPageShowEditFormInitial() expected to be a reference, value given

Backtrace:

#0 /usr/share/mediawiki-tuleap-123/includes/GlobalFunctions.php(4016): Hooks::run(string, array, NULL)
#1 /usr/share/mediawiki-tuleap-123/includes/EditPage.php(2242): wfRunHooks(string, array)
#2 /usr/share/mediawiki-tuleap-123/includes/EditPage.php(458): EditPage->showEditForm()
#3 /usr/share/mediawiki-tuleap-123/includes/actions/EditAction.php(50): EditPage->edit()
#4 /usr/share/mediawiki-tuleap-123/includes/Wiki.php(428): EditAction->show()
#5 /usr/share/mediawiki-tuleap-123/includes/Wiki.php(292): MediaWiki->performAction(Article, Title)
#6 /usr/share/mediawiki-tuleap-123/includes/Wiki.php(588): MediaWiki->performRequest()
#7 /usr/share/mediawiki-tuleap-123/includes/Wiki.php(447): MediaWiki->main()
#8 /usr/share/mediawiki-tuleap-123/index.php(46): MediaWiki->run()
#9 /usr/share/tuleap/plugins/mediawiki/www/index.php(4): require_once(string)
#10 {main}