I have just files <https://gitlab.com/mailman/mailman/issues/311> which is about Mailman core allowing list's to be created with a slash '/' in the name.
Core validates listnames by ensuring the fqdn_listname is a valid email address. This is too liberal. RFC 5321 allows many characters in the local part of a list name. We don't allow quite all of them, but we allow this set [-0-9a-z!#$%&'*+./=?@_`{}~].
Since list names form parts of a URI, both in Postorius/HyperKitty and in the Core's REST API, it is clear that characters that will cause problems there should not be allowed. These include [#%&/?] and maybe others. Additionally, I don't think we want @ in an email address local part and + and = might cause problems with VERP which whittles it down to [-0-9a-z!$'*._`{}~], but I'm thinking of being even more conservative and going with just [-0-9a-z._].
I don't intend to change the email address validation except maybe to remove @, but the code is such that an address with multiple @ won't validate anyway.
I'd like feedback on this. What are your thoughts on what characters should be allowed in list names?
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan