[bug#65745] gnu: yelp: Provide dependencies to display "man:" URIs.

Previously a command like the following one would fail to display the
expected man page:

  guix shell yelp coreutils man-db -C \
     --expose=/tmp/.X11-unix --expose=/run/user \
     --expose=/var/run/dbus --expose=/etc/machine-id \
     -E ^DISPLAY -- yelp man:ls

* gnu/packages/gnome.scm (yelp)[arguments]: New field.
[inputs]: Add 'man-db' and its "groff-minimal" input.

Reported-by: Luis Felipe <sirgazil@zoho.com>
---
 gnu/packages/gnome.scm | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

Hi!

Initially I wanted to fix support for URLs like “info:coreutils”,
which Luis also reported on the Fediverse as being broken.  However,
after much debugging I got lost in a maze of callbacks and threads
and opaque objects and eventually gave up.  Someone™ should take
another look.

For the record, this is how I went on my debugging journey:

  guix shell yelp coreutils man-db info-reader \
    --with-debug-info=yelp gdb --pure -E ^DISPLAY -- \
    gdb --args /bin/sh yelp info:coreutils

Ludo’.


base-commit: 1af35bbb25b122cafddfd2f69b644d46c4beff85
  

Hello,

Ludovic Courtès <ludo@gnu.org> writes:

[...]

> diff --git a/gnu/packages/gnome.scm b/gnu/packages/gnome.scm
> index 3b80692e90..894d77d7ba 100644
> --- a/gnu/packages/gnome.scm
> +++ b/gnu/packages/gnome.scm
> @@ -7336,6 +7336,31 @@ (define-public yelp
>                 (base32
>                  "0h9vf4fx056imjf8ibmn03wg1c3hniipy1nsm2jqi62lp1m19c95"))))
>      (build-system glib-or-gtk-build-system)
> +    (arguments
> +     (list #:phases
> +           #~(modify-phases %standard-phases
> +               (add-after 'unpack 'set-man-file-name
> +                 (lambda* (#:key inputs outputs #:allow-other-keys)
> +                   ;; Create a wrapper for 'man' that knows where to find
> +                   ;; 'groff' and 'gunzip'.
> +                   (define libexecdir
> +                     (string-append #$output "/libexec/yelp"))
> +                   (define wrapper
> +                     (string-append libexecdir "/man"))
> +
> +                   (mkdir-p libexecdir)
> +                   (symlink (search-input-file inputs "bin/man") wrapper)
> +                   (wrap-program wrapper
> +                     `("PATH" ":" =
> +                       ,(map (lambda (program)
> +                               (dirname (search-input-file inputs program)))
> +                             '("bin/groff" "bin/gunzip"))))
> +
> +                   ;; Have Yelp use that 'man' wrapper instead of searching
> +                   ;; for 'man' in $PATH.
> +                   (substitute* "libyelp/yelp-man-parser.c"
> +                     (("\"man\"")
> +                      (string-append "\"" wrapper "\""))))))))

Couldn't we more simply wrap the yelp command with the 'man', 'groff' and
'gunzip' command locations added to PATH?
  

Hi,

Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:

>> +                   ;; Create a wrapper for 'man' that knows where to find
>> +                   ;; 'groff' and 'gunzip'.
>> +                   (define libexecdir
>> +                     (string-append #$output "/libexec/yelp"))
>> +                   (define wrapper
>> +                     (string-append libexecdir "/man"))
>> +
>> +                   (mkdir-p libexecdir)
>> +                   (symlink (search-input-file inputs "bin/man") wrapper)
>> +                   (wrap-program wrapper
>> +                     `("PATH" ":" =
>> +                       ,(map (lambda (program)
>> +                               (dirname (search-input-file inputs program)))
>> +                             '("bin/groff" "bin/gunzip"))))
>> +
>> +                   ;; Have Yelp use that 'man' wrapper instead of searching
>> +                   ;; for 'man' in $PATH.
>> +                   (substitute* "libyelp/yelp-man-parser.c"
>> +                     (("\"man\"")
>> +                      (string-append "\"" wrapper "\""))))))))
>
> Couldn't we more simply wrap the yelp command with the 'man', 'groff' and
> 'gunzip' command locations added to PATH?

Yeah it’s convoluted; the idea was that the wrapper for ‘man’ is
something that should be fixed in ‘man-db’ proper but that we cannot fix
in ‘master’ because ‘man-db’ has too many dependents.

Maybe I should start with it though…

Ludo’.
  

Am Samstag, dem 09.09.2023 um 18:45 +0200 schrieb Ludovic Courtès:
> Hi,
> 
> Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:
> 
> > > +                   ;; Create a wrapper for 'man' that knows
> > > where to find
> > > +                   ;; 'groff' and 'gunzip'.
> > > +                   (define libexecdir
> > > +                     (string-append #$output "/libexec/yelp"))
> > > +                   (define wrapper
> > > +                     (string-append libexecdir "/man"))
> > > +
> > > +                   (mkdir-p libexecdir)
> > > +                   (symlink (search-input-file inputs "bin/man")
> > > wrapper)
> > > +                   (wrap-program wrapper
> > > +                     `("PATH" ":" =
> > > +                       ,(map (lambda (program)
> > > +                               (dirname (search-input-file
> > > inputs program)))
> > > +                             '("bin/groff" "bin/gunzip"))))
> > > +
> > > +                   ;; Have Yelp use that 'man' wrapper instead
> > > of searching
> > > +                   ;; for 'man' in $PATH.
> > > +                   (substitute* "libyelp/yelp-man-parser.c"
> > > +                     (("\"man\"")
> > > +                      (string-append "\"" wrapper "\""))))))))
> > 
> > Couldn't we more simply wrap the yelp command with the 'man',
> > 'groff' and
> > 'gunzip' command locations added to PATH?
> 
> Yeah it’s convoluted; the idea was that the wrapper for ‘man’ is
> something that should be fixed in ‘man-db’ proper but that we cannot
> fix
> in ‘master’ because ‘man-db’ has too many dependents.
> 
> Maybe I should start with it though…
Can we graft our man-db to get the same effect?
  

Hi,

Liliana Marie Prikler <liliana.prikler@gmail.com> writes:

> Am Samstag, dem 09.09.2023 um 18:45 +0200 schrieb Ludovic Courtès:
>> Hi,
>> 
>> Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:
>> 
>> > > +                   ;; Create a wrapper for 'man' that knows
>> > > where to find
>> > > +                   ;; 'groff' and 'gunzip'.
>> > > +                   (define libexecdir
>> > > +                     (string-append #$output "/libexec/yelp"))
>> > > +                   (define wrapper
>> > > +                     (string-append libexecdir "/man"))
>> > > +
>> > > +                   (mkdir-p libexecdir)
>> > > +                   (symlink (search-input-file inputs "bin/man")
>> > > wrapper)
>> > > +                   (wrap-program wrapper
>> > > +                     `("PATH" ":" =
>> > > +                       ,(map (lambda (program)
>> > > +                               (dirname (search-input-file
>> > > inputs program)))
>> > > +                             '("bin/groff" "bin/gunzip"))))
>> > > +
>> > > +                   ;; Have Yelp use that 'man' wrapper instead
>> > > of searching
>> > > +                   ;; for 'man' in $PATH.
>> > > +                   (substitute* "libyelp/yelp-man-parser.c"
>> > > +                     (("\"man\"")
>> > > +                      (string-append "\"" wrapper "\""))))))))
>> > 
>> > Couldn't we more simply wrap the yelp command with the 'man',
>> > 'groff' and
>> > 'gunzip' command locations added to PATH?
>> 
>> Yeah it’s convoluted; the idea was that the wrapper for ‘man’ is
>> something that should be fixed in ‘man-db’ proper but that we cannot
>> fix
>> in ‘master’ because ‘man-db’ has too many dependents.
>> 
>> Maybe I should start with it though…
> Can we graft our man-db to get the same effect?

We also have a core-updates branch; it could go there and we could merge
it with the docbook stuff that's going to go there.

I'd prefer this than convoluted solutions I don't understand :-).

-- 
Thanks,
Maxim