bug#74630: 31.0.50; emacs-mail-verify

bug#74630: 31.0.50; emacs-mail-verify

[Richard Stallman]

The doc string of `emacs-mail-verify' does not say how it
indicates that the signature is valid, or how it indicates
that the signature is not valid.

Would someone please add that to its doc string?


In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 2.24.33, cairo version 1.16.0) of 2024-08-01 built on freetop
Repository revision: a2c439db687774f7b57959c39560993579c5d1bd
Repository branch: master
System Description: Trisquel GNU/Linux Aramo (11.0)

Configured using:
 'configure 'CFLAGS=-O0 -g' --with-gnutls=ifavailable'

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GPM GSETTINGS HARFBUZZ JPEG LIBOTF
LIBSELINUX LIBXML2 M17N_FLT MODULES NOTIFY INOTIFY PDUMPER PNG RSVG
SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE XIM XINPUT2
XPM GTK2 ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: ELisp/l

Minor modes in effect:
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  auto-composition-mode: linux
  auto-encryption-mode: t
  auto-compression-mode: t
  abbrev-mode: t

Load-path shadows:
None found.

Features:
(shadow emacsbug epa-file vc-git diff-mode track-changes easy-mmode
vc-dispatcher bug-reference find-func shortdoc comp-common rx apropos
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generator xref project rmailkwd cl-extra help-mode shell pcomplete
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idna-mapping ucs-normalize uni-confusable textsec-check shr pixel-fill
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term/common-win x-dnd touch-screen tool-bar dnd fontset image
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Memory information:
((conses 16 622712 118122) (symbols 48 15101 10)
 (strings 32 79308 9073) (string-bytes 1 1459899) (vectors 16 57657)
 (vector-slots 8 1411286 252804) (floats 8 142 345)
 (intervals 56 69856 759) (buffers 984 77))
[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]


-- 
Dr Richard Stallman (https://stallman.org)
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)

bug#74630: 31.0.50; emacs-mail-verify

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Date: Sun, 01 Dec 2024 00:39:00 -0500
> 
> 
> The doc string of `emacs-mail-verify' does not say how it
> indicates that the signature is valid, or how it indicates
> that the signature is not valid.

I guess you meant epa-mail-verify?

> Would someone please add that to its doc string?

Not sure what you expected the doc string to say.  Would the below be
enough?

  Verify OpenPGP cleartext signed messages in the current buffer.
  The buffer is expected to contain a mail message.

  If the verification fails, the command signals an error.

The last sentence describes the following snippet from
epa-verify-region, which epa-mail-verify calls:

    (unless (epg-context-result-for context 'verify)
      (error "Unable to verify region"))

There are also other reasons to signal an error, e.g. if there are no
"-----BEGIN PGP SIGNED MESSAGE-----" line.  But eventually, all of the
problems cause an error.

If this is somehow not detailed enough, then I'm afraid someone else,
who knows the code, will have to improve the doc string, because I
could see no clear description in the code what values could the
context-result have and what is the meaning of each result.  Maybe I
missed something.

bug#74630: 31.0.50; emacs-mail-verify

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > I guess you meant epa-mail-verify?

Oops, yes.

  > Not sure what you expected the doc string to say.  Would the below be
  > enough?

  >   Verify OpenPGP cleartext signed messages in the current buffer.
  >   The buffer is expected to contain a mail message.

  >   If the verification fails, the command signals an error.

That is better, becauee it gives enough information to deduce what
indicates success.  But the user should need to do any deduction about
that, let alone read code and guess what some other functions do.

To make the doc string truly clear, it should say explicitly what
indicates success.  That way the user can know, rather than just
supposing.

Should the function be changed to display a message, "Signature verified",
on success?

Do some people run this function from a hook for every message and
want to see output only in case of failure?

Should it a value indicating success or failure?


-- 
Dr Richard Stallman (https://stallman.org)
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)

bug#74630: 31.0.50; emacs-mail-verify

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Cc: 74630@debbugs.gnu.org
> Date: Wed, 04 Dec 2024 01:09:05 -0500
> 
>   > Not sure what you expected the doc string to say.  Would the below be
>   > enough?
> 
>   >   Verify OpenPGP cleartext signed messages in the current buffer.
>   >   The buffer is expected to contain a mail message.
> 
>   >   If the verification fails, the command signals an error.
> 
> That is better, becauee it gives enough information to deduce what
> indicates success.  But the user should need to do any deduction about
> that, let alone read code and guess what some other functions do.

Thanks, I installed a change along those lines.

> To make the doc string truly clear, it should say explicitly what
> indicates success.  That way the user can know, rather than just
> supposing.

I don't know how to describe success in this case, except as the lack
of an error.

> Should the function be changed to display a message, "Signature verified",
> on success?

It says "Verifying...done", which I think is enough (and quite
standard in Emacs).

> Do some people run this function from a hook for every message and
> want to see output only in case of failure?

See above: it displays a message in case of success as well.

> Should it a value indicating success or failure?

I don't know.  The values of the relevant functions don't seem to be
documented.