bug#68947: 30.0.50; Gnus article mode keybindings

bug#68947: 30.0.50; Gnus article mode keybindings

[Pranshu]

Recipe from emacs -q:
1. M-x gnus
2. Select any group
3. Select a random article
4. do `W C-h' or C-h m

W C-h simply does not work while C-h m works, but does not show the
bound keys.


In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.41, cairo version 1.18.0) of 2024-02-02 built on localhost
Repository revision: d89e427852a63dbeed3d5e03d9deb2ae9a8e3e1b
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101011
System Description: Parabola GNU/Linux-libre

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bug#68947: 30.0.50; Gnus article mode keybindings

[Eric Abrahamsen]

Pranshu <pranshusharma366@gmail.com> writes:

> Recipe from emacs -q:
> 1. M-x gnus
> 2. Select any group
> 3. Select a random article
> 4. do `W C-h' or C-h m
>
> W C-h simply does not work while C-h m works, but does not show the
> bound keys.

FWIW I'm unable to reproduce this, using Emacs master. I'd be pretty
surprised if Gnus were able to break such low-level functionality, too.
Can you give us any more clues? Is this something that only started
happening recently?

bug#68947: 30.0.50; Gnus article mode keybindings

[Andreas Schwab]

On Feb 06 2024, Pranshu wrote:

> Recipe from emacs -q:
> 1. M-x gnus
> 2. Select any group
> 3. Select a random article
> 4. do `W C-h' or C-h m
>
> W C-h simply does not work while C-h m works, but does not show the
> bound keys.

In gnus-article-mode, all self-inserting keys are bound to
gnus-article-read-summary-keys, which does special things.  They are
_not_ prefix keys.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

bug#68947: 30.0.50; Gnus article mode keybindings

[Eric Abrahamsen]

Andreas Schwab <schwab@suse.de> writes:

> On Feb 06 2024, Pranshu wrote:
>
>> Recipe from emacs -q:
>> 1. M-x gnus
>> 2. Select any group
>> 3. Select a random article
>> 4. do `W C-h' or C-h m
>>
>> W C-h simply does not work while C-h m works, but does not show the
>> bound keys.
>
> In gnus-article-mode, all self-inserting keys are bound to
> gnus-article-read-summary-keys, which does special things.  They are
> _not_ prefix keys.

(I didn't realize you meant with point in the article, sorry)

bug#68947: 30.0.50; Gnus article mode keybindings

[Eric Abrahamsen]

On 02/07/24 22:19 PM, Pranshu wrote:
> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>
>> Pranshu <pranshusharma366@gmail.com> writes:
>>
>>> Recipe from emacs -q:
>>> 1. M-x gnus
>>> 2. Select any group
>>> 3. Select a random article
>>> 4. do `W C-h' or C-h m
>>>
>>> W C-h simply does not work while C-h m works, but does not show the
>>> bound keys.
>>
>> FWIW I'm unable to reproduce this, using Emacs master. I'd be pretty
>> surprised if Gnus were able to break such low-level functionality, too.
>> Can you give us any more clues? Is this something that only started
>> happening recently?
>
> With the point in article mode, are you able to reproduce it?

(Sending this back to the bug report...)

Yes, I'm able to reproduce it, and it sent me down a really awful rabbit
hole -- gnus-art.el goes to huge lengths to make summary-mode
keybindings available in article mode. It uses this:

(substitute-key-definition
 #'undefined #'gnus-article-read-summary-keys gnus-article-mode-map)

to redirect all unbound keys to the `gnus-article-read-summary-keys'
function, which manually reads keys and dispatches to tweaked versions
of summary-mode commands.

Your immediate issue is caused by the fact that
`gnus-article-describe-bindings', which theoretically should be
responsible for telling the user about all the redirections, is only
aware of the "S" keymap prefix. It doesn't know all the ways in which an
'undefined binding might get translated into a valid summary-mode
command, and can't show you those.

To be honest, I don't think I'm going to be able to fix this. If we keep
the current implementation, `gnus-article-describe-bindings' would have
to be made aware of the additional redirections, and I wouldn't even
know where to start.

It could be that Elisp has better tools for this situation by now (the
original architecture was in place before 1997), but I'm not sure what
those tools are. Perhaps someone will chime in with a helpful
suggestion...

Eric

bug#68947: 30.0.50; Gnus article mode keybindings

[Eli Zaretskii]

> Cc: 68947@debbugs.gnu.org
> From: Eric Abrahamsen <eric@ericabrahamsen.net>
> Date: Sat, 10 Feb 2024 10:09:14 -0800
> 
> Your immediate issue is caused by the fact that
> `gnus-article-describe-bindings', which theoretically should be
> responsible for telling the user about all the redirections, is only
> aware of the "S" keymap prefix. It doesn't know all the ways in which an
> 'undefined binding might get translated into a valid summary-mode
> command, and can't show you those.
> 
> To be honest, I don't think I'm going to be able to fix this. If we keep
> the current implementation, `gnus-article-describe-bindings' would have
> to be made aware of the additional redirections, and I wouldn't even
> know where to start.
> 
> It could be that Elisp has better tools for this situation by now (the
> original architecture was in place before 1997), but I'm not sure what
> those tools are. Perhaps someone will chime in with a helpful
> suggestion...

Strange as it may sound, I see no grave problem here: C-h is not
guaranteed to work after any arbitrary prefix, anyway.  So if that is
too hard to fix, we could just punt and leave it unsolved.

What about "C-h b" -- does that work in the situation described by the
recipe?

bug#68947: 30.0.50; Gnus article mode keybindings

[Eric Abrahamsen]

On 02/10/24 20:15 PM, Eli Zaretskii wrote:
>> Cc: 68947@debbugs.gnu.org
>> From: Eric Abrahamsen <eric@ericabrahamsen.net>
>> Date: Sat, 10 Feb 2024 10:09:14 -0800
>> 
>> Your immediate issue is caused by the fact that
>> `gnus-article-describe-bindings', which theoretically should be
>> responsible for telling the user about all the redirections, is only
>> aware of the "S" keymap prefix. It doesn't know all the ways in which an
>> 'undefined binding might get translated into a valid summary-mode
>> command, and can't show you those.
>> 
>> To be honest, I don't think I'm going to be able to fix this. If we keep
>> the current implementation, `gnus-article-describe-bindings' would have
>> to be made aware of the additional redirections, and I wouldn't even
>> know where to start.
>> 
>> It could be that Elisp has better tools for this situation by now (the
>> original architecture was in place before 1997), but I'm not sure what
>> those tools are. Perhaps someone will chime in with a helpful
>> suggestion...
>
> Strange as it may sound, I see no grave problem here: C-h is not
> guaranteed to work after any arbitrary prefix, anyway.  So if that is
> too hard to fix, we could just punt and leave it unsolved.

I'm inclined to say it's too hard to fix! The only cleaner solution I
can think of is to actually define article-mode versions of all the
summary-mode commands we'd want to call, which would also provide a
place to do the necessary article-specific adjustments. That's a lot of
very tightly-coupled code, though.

> What about "C-h b" -- does that work in the situation described by the
> recipe?

No, that doesn't really work. The gnus-article-mode bindings are listed
under a "fundamental-mode Major Mode Bindings:" heading (??). That
includes gnus-article-mode's own keybindings, and the summary-mode
bindings that have been explicitly attached at the "S" prefix, but
nothing else.

bug#68947: 30.0.50; Gnus article mode keybindings

[Eric Abrahamsen]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> On 02/10/24 20:15 PM, Eli Zaretskii wrote:
>>> Cc: 68947@debbugs.gnu.org
>>> From: Eric Abrahamsen <eric@ericabrahamsen.net>
>>> Date: Sat, 10 Feb 2024 10:09:14 -0800
>>> 
>>> Your immediate issue is caused by the fact that
>>> `gnus-article-describe-bindings', which theoretically should be
>>> responsible for telling the user about all the redirections, is only
>>> aware of the "S" keymap prefix. It doesn't know all the ways in which an
>>> 'undefined binding might get translated into a valid summary-mode
>>> command, and can't show you those.
>>> 
>>> To be honest, I don't think I'm going to be able to fix this. If we keep
>>> the current implementation, `gnus-article-describe-bindings' would have
>>> to be made aware of the additional redirections, and I wouldn't even
>>> know where to start.
>>> 
>>> It could be that Elisp has better tools for this situation by now (the
>>> original architecture was in place before 1997), but I'm not sure what
>>> those tools are. Perhaps someone will chime in with a helpful
>>> suggestion...
>>
>> Strange as it may sound, I see no grave problem here: C-h is not
>> guaranteed to work after any arbitrary prefix, anyway.  So if that is
>> too hard to fix, we could just punt and leave it unsolved.
>
> I'm inclined to say it's too hard to fix! The only cleaner solution I
> can think of is to actually define article-mode versions of all the
> summary-mode commands we'd want to call, which would also provide a
> place to do the necessary article-specific adjustments. That's a lot of
> very tightly-coupled code, though.
>
>> What about "C-h b" -- does that work in the situation described by the
>> recipe?
>
> No, that doesn't really work. The gnus-article-mode bindings are listed
> under a "fundamental-mode Major Mode Bindings:" heading (??). That
> includes gnus-article-mode's own keybindings, and the summary-mode
> bindings that have been explicitly attached at the "S" prefix, but
> nothing else.

I don't know, I don't see a good solution to this without a massive
rewrite, which I don't have the stomach for right now. Should we leave
the bug open, since it's a real problem?

bug#68947: 30.0.50; Gnus article mode keybindings

[Eli Zaretskii]

> From: Eric Abrahamsen <eric@ericabrahamsen.net>
> Cc: pranshusharma366@gmail.com,  68947@debbugs.gnu.org
> Date: Sat, 17 Feb 2024 10:13:02 -0800
> 
> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
> 
> > On 02/10/24 20:15 PM, Eli Zaretskii wrote:
> >>> Cc: 68947@debbugs.gnu.org
> >>> From: Eric Abrahamsen <eric@ericabrahamsen.net>
> >>> Date: Sat, 10 Feb 2024 10:09:14 -0800
> >>> 
> >>> Your immediate issue is caused by the fact that
> >>> `gnus-article-describe-bindings', which theoretically should be
> >>> responsible for telling the user about all the redirections, is only
> >>> aware of the "S" keymap prefix. It doesn't know all the ways in which an
> >>> 'undefined binding might get translated into a valid summary-mode
> >>> command, and can't show you those.
> >>> 
> >>> To be honest, I don't think I'm going to be able to fix this. If we keep
> >>> the current implementation, `gnus-article-describe-bindings' would have
> >>> to be made aware of the additional redirections, and I wouldn't even
> >>> know where to start.
> >>> 
> >>> It could be that Elisp has better tools for this situation by now (the
> >>> original architecture was in place before 1997), but I'm not sure what
> >>> those tools are. Perhaps someone will chime in with a helpful
> >>> suggestion...
> >>
> >> Strange as it may sound, I see no grave problem here: C-h is not
> >> guaranteed to work after any arbitrary prefix, anyway.  So if that is
> >> too hard to fix, we could just punt and leave it unsolved.
> >
> > I'm inclined to say it's too hard to fix! The only cleaner solution I
> > can think of is to actually define article-mode versions of all the
> > summary-mode commands we'd want to call, which would also provide a
> > place to do the necessary article-specific adjustments. That's a lot of
> > very tightly-coupled code, though.
> >
> >> What about "C-h b" -- does that work in the situation described by the
> >> recipe?
> >
> > No, that doesn't really work. The gnus-article-mode bindings are listed
> > under a "fundamental-mode Major Mode Bindings:" heading (??). That
> > includes gnus-article-mode's own keybindings, and the summary-mode
> > bindings that have been explicitly attached at the "S" prefix, but
> > nothing else.
> 
> I don't know, I don't see a good solution to this without a massive
> rewrite, which I don't have the stomach for right now. Should we leave
> the bug open, since it's a real problem?

Fine with me.