[bug#48443] [PATCH 1/2] gnu: Add texlive-libkpathsea.

[Leo Prikler <leo.prikler@student.tugraz.at>]

Hello Thiago,

Am Montag, den 12.07.2021, 21:32 -0300 schrieb Thiago Jung Bauermann:
> [...]
> > +(define-public texlive-libkpathsea
> > +  (package/inherit texlive-bin
> 
> According to a recent message from Ludo¹, ‘package/inherit’ is meant
> to be 
> used in specific situations, and IIUC it doesn’t apply here:
> 
> > It should also be (package (inherit …) …) rather than
> > (package/inherit …).  The latter is only useful when defining
> > variants of a package (same version, same code) where the same
> > security updates would apply.
I'm a little confused here, as that is exactly the rationale I'm
applying.  When texlive-bin gets grafted due to kpathsea, the graft
also applies to texlive-libkpathsea.  Granted, there is a large room
for false positives, that would result in gratuitous grafts for
texlive-libkpathsea, but I prefer erring on the side of security rather
than graftlessness here.

> I also wonder whether inheriting from texlive-bin is the best option.
> One disadvantage is that it makes this package too sensitive to
> changes in texlive-bin. As an example, it doesn’t work anymore with
> the version in core-updates because in the branch, the ‘postint’
> phase has been renamed to ‘post-install’. Also, I assume many
> texlive-bin inputs aren’t needed for texlive-kpathsea, causing
> unnecessary work when building texlive-libkpathsea and packages
> depending on it such as evince.
The postinst thing was my mistake – instead of inheriting from
%standard-phases as I should, I naïvely inherited texlive-bin's phases
instead.  It turns out, I actually don't need any of those (and if I
did they'd be trivially copyable).

On the part of inputs, sure, we could make libkpathsea smaller, but I
have little experience with TeX Live and its build system, so I decided
not to change its inputs for now.  If you have suggestions on how a
better closure could be achieved, please do bring them forth.

> In addition, if it were a separate package then texlive-bin could be
> made to use it, rather than shipping its own copy.

Perhaps that's an idea worth entertaining, but given the TeX Live build
system I fear it's not an overwhelmingly practical one.

> > +    (name "texlive-libkpathsea")
> > +    (source
> > +     (origin
> > +       (inherit (package-source texlive-bin))
> 
> Perhaps a ‘texlive-source-src’ variable analogous to ‘texlive-extra-
> src’ and ‘texlive-texmf-src’ would be useful?

I'm… not too sure on this one.  What would texlive-source-src capture? 
Just the upstream source?  Then we'd have to carefully apply all the
fitting patches.  The same as (package-source texlive-bin)?  What's the
point then?

> > +       (snippet
> > +        `(begin
> > +           ,(origin-snippet (package-source texlive-bin))
> > +           (with-directory-excursion "texk"
> > +             (let ((preserved-directories '("." ".." "kpathsea")))
> > +               (for-each
> > +                delete-file-recursively
> > +                (scandir "."
> > +                         (lambda (file)
> > +                           (and (not (member file
> > preserved-directories)) +                                (eq?
> > 'directory
> > (stat:type (stat file))))))))))))) +    (arguments
> > +     (substitute-keyword-arguments (package-arguments texlive-bin)
> > +       ((#:configure-flags flags)
> > +        `(cons* "--disable-all-pkgs" "--enable-kpathsea"
> > +                "--enable-shared" ,flags))
> > +       ((#:phases phases)
> > +        `(modify-phases ,phases
> > +           (delete 'configure-ghostscript-executable)
> > +           (delete 'use-code-for-new-poppler)
> > +           (delete 'patch-dvisvgm-build-files)
> > +           (delete 'disable-failing-test)
> > +           (replace 'postint
> > +             (lambda* (#:key inputs outputs #:allow-other-keys)
> > +               (with-directory-excursion "texk/kpathsea"
> > +                 (invoke "make" "install"))))))))))
> 
> If you decide to continue inheriting from texlive-bin, you’d also
> need to change the synopsis and description.
Fair enough, that's on me.  I've sent a v2 applying some of your
suggestions.  Please feel free to point out anything I've missed or you
noticed in addition to what's already discussed.

Regards,
Leo