Last modified: 2010-11-19 23:11:26 UTC
When creating tag extensions, attribute names with underscore as the initial character (e.g. _attr, _file, etc.) are not recognized as valid attributes. This is a valid attribute name according to W3C XML standard (http://www.w3.org/TR/REC-xml/#NT-NameStartChar), which, if I understand correctly, mediawiki tries to comply with. I don't see a reason why these attributes should not be allowed.
Is this actually an API specific bug? The parser tag seems wrong (removing). Also, you're testing again 1.15.5? :S
My apologies. I tested it in the latest SVN version and underscore has been added as a valid first character. Non-english characters are still invalid, but that's a different issue (I have seen some comments about that on the wikimedia website). Sorry once again, I should have checked.