bug#51335: 29.0.50; Use warnings facility for reporting Gnus errors

[Eric Abrahamsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>
>> I haven't changed how `gnus-verbose' works, so that filter does the same
>> thing it always has. The only real difference is that messages/errors go
>> into a dedicated buffer, and the user has the option to keep the buffer
>> hidden (the default), pop it up with a command, or fit it into their
>> existing Gnus window configuration however they like.
>
> Sounds good.

Well, I'm about 75% happy with this. I've attached both the patch I'm
running, and a screenshot of my *Group* configuration with the logging
window visible (I've set `gnus-verbose' to 10). I will suppress the urge
to apologize for my *Group* buffer appearance, I'm in the middle of some
home improvements.

The rightmost blob is the warning category: the "(gnus)". With fuller
adoption it might look like "(gnus nntp)" or "(gnus draft)" or "(gnus
search)", etc. I've made it so `gnus-add-timestamp-to-message' also adds
a timestamp here, though that's not activated in the screenshot.

The main awkwardness come from the fact that warnings.el is kind of set
up for you to incorporate it into other packages, but kind of not. You
can opt to split warnings off into your own buffer, which is great. But
in this case, whether and how warnings are logged and/or displayed
should be mostly controlled by Gnus' existing mechanisms (window
configuration and `gnus-verbose'), and I'm fighting warnings.el on that:

- `warning-suppress-types' should belong solely to the user, but I have
  to push `(gnus)' onto it to shut off automatic display, and move
  display control to Gnus's own knobs.
- There's no :info warning level, and it's unclear if `warning-levels'
  is fair game for packages to fool with. Instructions are given, but
  pushing your own values there will mess up eg `warning-numeric-level',
  and it's hard to know if it's really okay.
- The biggest eyesore in the screenshot is the acres of "disable showing
  disable logging" buttons, which are hardcoded. Again, Gnus has its own
  knobs for these.

Lastly, the messages coming from Gnus are very much set up for regular
message display, in particular the "<message>...done" pattern, which
doesn't work with the warnings setup. If we only use delayed warnings
then each time the warnings are output it runs `delayed-warnings-hook',
which runs `collapse-delayed-warnings', which might be an okay place to
collapse the "...done" lines into one. That hook is supposed to run as
part of the `post-command-hook', though, and it doesn't always run, and
I haven't figured out why yet.

All in all, it nearly works :( Probably there would need to be some
small design changes to warnings.el to make it nice. I still think this
or something like it is worth doing.

Eri

screenshot.png
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0001-WIP-on-using-warnings-in-Gnus.patch
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