bug#43356: 27.1; Gnus: Selected articles are unavoidably entered into the agent cache in an agentized group (while plugged)

bug#43356: 27.1; Gnus: Selected articles are unavoidably entered into the agent cache in an agentized group (while plugged)

[Ozhap]

Sample way to reproduce the behaviour:
1. Gmail IMAP should be accessible. Keep credentials in .authinfo.gpg.
   No Gnus files or directories (News, .newsrc*, Mail) present.
2. emacs -Q
3. Run:

(setq gnus-select-method
      '(nnimap "gmail"
	       (nnimap-address "imap.gmail.com")
	       (nnimap-server-port 993)
	       (nnimap-stream ssl)))

4. M-x gnus
5. ^ (Server list)
6. Go to 'gmail' and: J a (agentize)
7. q (back to Group buffer)
8. g (refresh)
9. RET on any folder and RET on an article
10. Verify that an article file has been created in
    ~/News/agent/nnimap/gmail/[folder]/

This also conflicts with the documentation in the manual sections
'Agent Caveats' (see below), 'Choosing Variables' & 'Agent as Cache',
the latter saying:

"Articles are not cached in the Agent by default though (that would
potentially consume lots of disk space), but if you have already
downloaded an article into the Agent, Gnus will not download the
article from the server again but use the locally stored copy instead"

Apparently, this has been brought about (intentionally) by commit
f3b146e943cd733fb716c75048f24b73826e5f30 in response to what appears
to be an erroneous feature-request - bug#8502 [1]. The requested
feature already existed, as documented in the manual sections
'Choosing Variables' & 'Agent Caveats', the latter reading thus:

“If I read an article while plugged, do they get entered into the
Agent?”

     *No*. If you want this behavior, add
     ‘gnus-agent-fetch-selected-article’ to
     ‘gnus-select-article-hook’.

In my limited understanding, the fix is simple: revert the commit
(except for 2 of its unrelated hunks - of gnus-html.el & shr.el).

Ref:
[1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=8502
[2] Related thread:
https://lists.gnu.org/archive/html/help-gnu-emacs/2020-09/msg00099.html




In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.20)
 of 2020-08-11 built on Kittu
Repository revision: 86d8d76aa36037184db0b2897c434cdaab1a9ae8
Repository branch: HEAD
Windowing system distributor 'The X.Org Foundation', version 11.0.12008000
System Description: Ubuntu 20.04.1 LTS

Recent messages:
nnimap read 7k from imap.gmail.com (initial sync of 6 groups; please wait)
Checking new news...done
Entered nnimap:gmail into the Agent
Checking new news...
nnimap read 0k from imap.gmail.com
Reading active file via nndraft...done
Checking new news...done
nnimap read 0k from imap.gmail.com
C-x 5 C-x C-f is undefined
Making completion list... [6 times]

Configured using:
 'configure --prefix=/home/jim/emacs'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND GPM DBUS GSETTINGS GLIB NOTIFY INOTIFY
ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD PDUMPER
LCMS2 GMP

Important settings:
  value of $LANG: en_IN
  locale-coding-system: iso-latin-1-unix

Major mode: Fundamental

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Load-path shadows:
None found.

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ansi-color shr-color color mm-archive mail-extr gnus-async gnus-bcklg
gnus-ml disp-table cursor-sensor nndraft nnmh nnfolder utf-7 epa-file
gnutls network-stream nsm gnus-agent gnus-srvr gnus-score score-mode
nnvirtual gnus-msg gnus-art mm-uu mml2015 mm-view mml-smime smime dig
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json map url-vars svg xml dom browse-url gnus-group gnus-undo gnus-start
gnus-cloud nnimap nnmail mail-source utf7 netrc nnoo parse-time iso8601
gnus-spec gnus-int gnus-range message rmc puny dired dired-loaddefs
format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg
epg-config mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader gnus-win gnus nnheader gnus-util rmail
rmail-loaddefs rfc2047 rfc2045 ietf-drums text-property-search time-date
subr-x seq byte-opt gv bytecomp byte-compile cconv mail-utils mm-util
mail-prsvr wid-edit cl-loaddefs cl-lib tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
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button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
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 (symbols 48 15095 1)
 (strings 32 45089 3333)
 (string-bytes 1 1574228)
 (vectors 16 23104)
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 (buffers 1000 28))

bug#43356: 27.1; Gnus: Selected articles are unavoidably entered into the agent cache in an agentized group (while plugged)

[Lars Ingebrigtsen]

Ozhap <ozhap@vollbio.de> writes:

> Apparently, this has been brought about (intentionally) by commit
> f3b146e943cd733fb716c75048f24b73826e5f30 in response to what appears
> to be an erroneous feature-request - bug#8502 [1]. The requested
> feature already existed, as documented in the manual sections
> 'Choosing Variables' & 'Agent Caveats', the latter reading thus:
>
> “If I read an article while plugged, do they get entered into the
> Agent?”
>
>      *No*. If you want this behavior, add
>      ‘gnus-agent-fetch-selected-article’ to
>      ‘gnus-select-article-hook’.
>
> In my limited understanding, the fix is simple: revert the commit
> (except for 2 of its unrelated hunks - of gnus-html.el & shr.el).

Thanks for the thorough and clear analysis.

I've now reverted the parts from that commit that were relevant to this
issue.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#43356: fix misguided

[Madhu]

Please consider reverting the reverts and maintaining the old code
paths.  Old functionality is *not* available after the change commit
def34a20.

The restored "old behaiour" which is desired includes that

(a) *all* articles which are read when
(b) gnus-agent is t and
(c) and the group is agentised
are cached in the agent cache.

This means that 1) articles in groups which are not agentised should
not be cached in the agent cache. 2) when gnus-agent is nil articles
should not be cached in the agent cache.

The commit def34a20 suggests that one could get the old behaviour by
adding `gnus-agent-fetch-selected-article' to
`gnus-select-article-hook'

First problem is that this adds a 0.5 to 2 seconds overhead on
selecting each article.  Initial tests with ELP show that
`gnus-agent-fetch-articles' which is called for each article is over
100 times slower than than `gnus-agent-store-article' (which this
commit deprecates and removes from use).

When articles are missed by the hook there is no user interface to
ensure that the articles can be cached in the agent cache. There is no
way to fetch already fetched articles to the agent cache except by
selecting them again (painfully slow)

whether or not bug#8502 was an "erroneous feature request" this
particular "fix" is erroneous in the functionality it removes. here is
my rant on emacs-help:
https://lists.gnu.org/archive/html/help-gnu-emacs/2020-10/msg00037.html

bug#43356: fix misguided

[Ozhap]

Bug submitter here. I am in favour of reverting this until a proper fix
can be worked out someday - it is not at all critical for me. For my
part, I should have noted caution about the code being very old.

--
Ozhap

bug#43356: Gnus: Selected articles are unavoidably entered into the agent cache in an agentized group (while plugged)

[Lars Ingebrigtsen]

Ozhap <ozhap@vollbio.de> writes:

> Bug submitter here. I am in favour of reverting this until a proper fix
> can be worked out someday - it is not at all critical for me. For my
> part, I should have noted caution about the code being very old.

OK; reverted.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no