bug#28596: 26.0.60; Gnus gets into an ambiguous plugged/unplugged state that prevents retrieval of news

[N. Jackson]

At 14:38 -0400 on Wednesday 2018-07-04, N. Jackson wrote:
>
>>> At 19:50 +0300 on Wednesday 2018-07-04, Eli Zaretskii wrote:
>>>>
>>>> Is it possible for you to try the branch? I think it's
>>>> important to know whether this problem still exists on the
>>>> release branch.

> I have really built the emacs-26 branch [1] this time!
>
> As promised, I will use it from now on as my every-day Emacs and
> report back here if I see the bug again.
>
> [1] Repository revision: 0dce5e59206db7bd0b9cd43ae712272105300ae4

Yes, the problem still exists. Gnus got into the confused
plugged/unplugged state again this morning.

FWIW:

M-x emacs-uptime RET
==> 5 days, 0 hours, 26 minutes, 55 seconds

Memory information:
((conses 16 1153669 478417)
 (symbols 48 121724 355)
 (miscs 40 24187 11415)
 (strings 32 308736 20050)
 (string-bytes 1 12884595)
 (vectors 16 74179)
 (vector-slots 8 2504362 73640)
 (floats 8 2016 1881)
 (intervals 56 41378 48502)
 (buffers 992 323))

After Gnus got into the confused state and after trying for several
minutes to get it back to it's senses, I exited Gnus (but not Emacs) and
restarted Gnus (with M-x gnus RET) and it was still in it's stuck state
and it printed these messages as it started:

  20180712T104052.549> Reading /home/nlj/.newsrc.eld...
  20180712T104052.735> Opening nnfolder server on archive...
  20180712T104052.736> Opening nnfolder server on archive...done
  20180712T104052.737> Opening nntp server on nntp.olduse.net...
  20180712T104132.771> Opening nntp server on nntp.olduse.net...failed: >>> 
(error nntp.olduse.net/nntp Name or service not known)
  20180712T104132.772> Opening nntp server on nntp.aioe.org...
  20180712T104212.811> Opening nntp server on nntp.aioe.org...done
  20180712T104212.811> Opening nntp server on dusty...
  20180712T104252.851> Opening nntp server on dusty...failed: >>> (error 
news.gmane.org/nntp Name or service not known)
  20180712T104252.852> Opening nntp server on news.gmane.org...
  20180712T104332.887> Opening nntp server on news.gmane.org...done
  20180712T104332.887> Opening nnimap server on Local Dovecot Mailstore...
  20180712T104332.888> Opening connection to localhost via tls...
  20180712T104333.079> Opening connection to localhost...done
  20180712T104333.080> Opening nnimap server on Local Dovecot Mailstore...done
  20180712T104333.144> No new newsgroups
  20180712T104333.161> Checking new news...
  20180712T104333.164> Reading active file via nnnil...
  20180712T104333.164> Reading active file via nnnil...
  20180712T104333.164> Reading active file via nnnil...done
  20180712T104333.164> Reading active file from nntp.olduse.net via nntp...
  20180712T104333.164> Opening nntp server on nntp.olduse.net...
  20180712T104333.165> Server nntp+nntp.olduse.net previously determined to be 
down; not retrying
  20180712T104333.165> Opening nntp server on nntp.olduse.net...failed: >>> 
(error news.gmane.org/nntp Name or service not known)
  20180712T104333.192> Opening nntp server on nntp.aioe.org...
  20180712T104333.193> Opening nntp server on nntp.aioe.org...done
  20180712T104333.194> Opening nntp server on news.gmane.org...
  20180712T104333.195> Opening nntp server on news.gmane.org...done
  20180712T104333.201> nnimap read 0k from localhost
  20180712T104333.408> Reading active file from archive via nnfolder...
  20180712T104333.409> Opening nnfolder server on archive...
  20180712T104333.410> Opening nnfolder server on archive...done
  20180712T104333.410> Reading active file from archive via nnfolder...
  20180712T104333.411> Reading active file from archive via nnfolder...done
  20180712T104333.412> Reading active file via nnfolder...
  20180712T104333.412> Opening nnfolder server...
  20180712T104333.413> Opening nnfolder server...done
  20180712T104333.440> Reading incoming mail from file...
  20180712T104333.441> nnfolder: Reading incoming mail (no new mail)...done
  20180712T104333.442> Reading active file via nnfolder...
  20180712T104333.443> Reading active file via nnfolder...done
  20180712T104333.443> Reading active file via nndraft...
  20180712T104333.446> Reading active file via nndraft...
  20180712T104333.447> Reading active file via nndraft...done
  20180712T104333.448> Checking new news...done
  Warning: Opening nntp server on nntp.olduse.net...failed: >>> (error 
news.gmane.org/nntp Name or service not known); Server nntp+nntp.olduse.net 
previously determined to be down; not retrying; Opening nntp server on 
dusty...failed: >>> (error news.gmane.org/nntp Name or service not known); 
Opening nntp server on nntp.olduse.net...failed: >>> (error 
nntp.olduse.net/nntp Name or service not known)

The errors for olduse.net happen all the time (I suspect the site has
gone away), so I assume they are unrelated, but the second message at
20180712T104333.165 seems odd: it appears to suggest that it was
checking olduse.net and gmane.org failed. Or maybe I'm just not reading
that right.

[The server I have set up with the name of "dusty" is on gmane, so the
messages about gmane not being known when checking dusty do make sense.]

I then exited Gnus and exited Emacs, restarted Emacs, restarted Gnus and
everything was back to working as normal.