bug#28596: 26.0.60; [Gnus] Checking mail is no longer reliable and C-g no longer quits

[Eric Abrahamsen]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: nljlistbox2@gmail.com (N. Jackson)
>> Date: Mon, 25 Sep 2017 11:01:01 -0400
>> 
>> Yesterday I switched from Emacs 25 to the emacs-26 branch. With
>> this Gnus hangs (sometimes) when checking mail/news
>> (`gnus-group-get-new-news') and then C-g no longer quits -- at
>> least not immediately.
>> 
>> The hangs are for long enough for Gnome dialogs to appear saying
>> that Emacs is no longer responding. Eventually control comes back
>> to Emacs but that might be due to repeated presses of C-g.
>
> This could be due to the fact that Emacs 26 uses async communications
> more than previous versions.
>
> Does gnus-group-get-new-news use any of the url-* functions?  If so,
> perhaps try setting url-asynchronous to nil when fetching news, to see
> if that solves the problem.  Or maybe even build Emacs with
> HAVE_GETADDRINFO_A undefined, and see if that helps.

FWIW, I would put money on `nntp-open-connection' being the culprit,
specifically the call to `open-network-stream'. I used to have similar
problems with Gnus connections hanging (including the need to restart
Emacs entirely to "clear" it out), and all my attempts at figuring it
out led me there. Unfortunately Gnus has been behaving pretty well for
me for the past six months to a year, so I might not be much more help
than that. But I remember being suspicious that these problems were
happening right around the time people seemed to be messing with the
behavior of gnutls. Could be a total red herring, though.