Since upgrading from 1.23.15 to 1.27.1 our wiki pages that use one of our templates are getting the above message when we preview an edit. Example: Warning: DP Official Documentation:General/wf-test-language is calling Template:Languages with more than one value for the "" parameter. Only the last value provided will be used.
MediaWiki level: 1.27.1 PHP: 5.5.9-1ubuntu4.21 (apache2handler) Database: MySQL 5.5.55-0ubuntu0.14.04.1
URL of wiki page that has this error: https://www.pgdp.org/wiki/DP_Official_Documentation:General/wf-test-language
The call to the Languages template looks like this:
{{Languages|Languages:|=
|en|{{NAMESPACE}}:General/Code of Conduct|=
|fr|{{NAMESPACE}}:General/French/Code de la Conduite|=
|es|{{NAMESPACE}}:General/Spanish/Código de Conducta|=
|de|{{NAMESPACE}}:General/German/Verhaltenskodex|=
}}
It uses a layout style suggested in https://meta.wikimedia.org/wiki/Special:MyLanguage/Help:Template#Template_tag_lay-out ending each line with |= to make the coding more legible to the page editor.
Since migrating to 1.27.1 that style results in the message shown above. To avoid the message we have to delete all the |= characters and collapse the template call onto one long line of wiki code. That makes it harder to maintain, so we would like to be able to use the formerly supported approach.