bug#64202: [PATCH] Gnus: Add back end for Atom feeds (nnatom)

[Daniel Semyonov via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

>>>>> Thomas Fitzsimmons writes:

    > Hi Daniel, Daniel Semyonov via <bug-gnu-emacs@gnu.org> writes:

    >>>>>>> Daniel Semyonov writes:
    >> 
    >> > I think this can be merged now.  Updated patch attached.
    >> 
    >> Here's another version which fixes a bunch of small mistakes and
    >> clarifies some information in the manual, docstrings and
    >> comments.

    > I am trying this, but am having no luck.

    > I applied the patch to Emacs master tip
    > (2a591b228aaa8c66c27cc5b7cb3033aa6625bc0b) and rebuilt.

    > I am starting from an empty home directory.  I customize
    > gnus-select-method to:

    >     (nnatom "www.fitzsim.org/blog/?feed=atom")

    > Then M-x gnus RET produces:

    >     nnatom (www.fitzsim.org/blog/?feed=atom) open error: ‘Server
    > file www.fitzsim.org/blog/?feed=atom not readable or writable’.
    > Continue? (y or n)

    > I instead configure gnus-select-method to (nnnil "") and restart
    > Gnus.  Then in the *Group* buffer, I press 'B', then select
    > nnatom, then paste in:

    >     www.fitzsim.org/blog/?feed=atom

    > and I see in the minibuffer:

    >     Unable to contact server www.fitzsim.org/blog/?feed=atom:
    > Server file www.fitzsim.org/blog/?feed=atom not readable or
    > writable

    > EWW loads both of the following without issue:

    >     https://www.fitzsim.org/blog/?feed=atom
    > www.fitzsim.org/blog/?feed=atom

Huh, I could've sworn I fixed this already.

This happens because you don't have an "atom" subdirectory in your
'gnus-directory'.  The backend *should* create it automatically, but
looking at the code it seems I forgot to implement this.  If you create
the directory manually it should work.  I'll send a patch with a fix as
soon as I can.

Thanks a lot for testing, I really appreciate it.

Daniel