Tags: patch

Reproduction steps:

- Setup Gnus with any group name having a slash ('/') such as
  "[Gmail]/Drafts" or an Atom feed (they usually have slashes) using the
  patch in bug#66188.

- Press '*' on a message in the group.

- Do (info "(gnus) Creating a Virtual Server")

- Open the above from the Server buffer; RET on the new group fails.

A patch is attached. I couldn't find the problematic commit or its
original branch (where it was a consolidated merge from) but
'gnus-use-long-file-names' is apparently not meant for backends: it
can't even be customized with that 'not-cache' option. I think this is
the right way to solve it: the other lines removed in this patch are
even older, but they were never being called due to the above reason.

In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.33, cairo version 1.16.0) of 2024-02-20 built on
 user-Inspiron-15-5518
Repository revision: 466800591c2bd674b0b967205147d7519da7e1a4
Repository branch: nnatom-master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Ubuntu 22.04.3 LTS