[bug#38390] [bug #38390] Building bootstrap Gash and Gash-Utils

["Ludovic Courtès" <ludo@gnu.org>]

Hello Timothy!

Timothy Sample <samplet@ngyro.com> skribis:

> We’re nearing a release for Gash-Utils, and while working on it I made
> some changes to how the bootstrap Gash and Gash-Utils are built (on the
> wip-bootstrap branch.)  Jan suggested that we get your opinion on the
> changes, as you are behind the current '%bootstrap-guile+guild'
> approach.

Thanks for reaching out to me!

> The very short story is that I found that the Scheme GZip code is being
> maintained and works out-of-the-box on Guile 2.0.9 [1].  This made me
> unsure about copying the code into Gash-Utils when maybe we could just
> use it as a dependency.  Then, I realized that the library included a
> simple Tar reader, and wondered how simple a program could be that could
> handle 'tar xvf gash.tar.gz'.  It turns out pretty simple!  So I put the
> program and all its dependencies in an a-list with a little loop that
> writes them to disk, and made a self-extracting Scheme script that can
> unpack compressed tarballs [2].

Woow, that is very nice!  So all of a sudden there’s an extra bunch of
binary seeds we can get rid of, woohoo!  I didn’t expect that even bzip2
and xz would be implemented.

> [2] https://git.ngyro.com/bootar/

Clean, short, and elegant; brilliant!

> The other thing is that I always intended for Gash and Gash-Utils to be
> built with a loop calling “compile-file”.  This avoids the need for
> “guild” which in turn avoids “bash” (AIUI).
>
> These patches update Gash-Utils, replace the binary “tar” with my
> self-extracting Scheme implementation, and replace “guild” with
> “compile-file”.  I think this simplifies the bootstrap processes, and I
> really like getting rid of the references to “tar”, “bash”, and “xz”
> (even though they are needed for the bootstrap Guile, it feels nice to
> quarantine them there).
>
> WDYT?

I think it’s perfect.

One comment that can be addressed later:

> From 2cec50928a4ff67df363322d2adfb6aaa5aedc83 Mon Sep 17 00:00:00 2001
> From: Timothy Sample <samplet@ngyro.com>
> Date: Mon, 3 Feb 2020 10:51:07 -0500
> Subject: [PATCH 2/3] Simplify bootstrap Gash and Gash-Utils.
>
> This change does three things.  First Gash-Utils is updated to
> 0.1.0-preview.  Then, the bootstrap Gash and Gash-Utils packages are
> arranged to be built without using 'guild'.  Finally, instead of
> using a binary 'tar' via 'bootstrap-executable' to extract Gash and
> Gash-Utils, a self-extracting Scheme implementation of 'tar' and
> 'gzip' is used instead.

[...]

> +(define (make-bootstrap-phases version scripts modules)
> +  "Create a form that modifies the standard GNU build phases so that
> +they build simple Guile programs using only the bootstrap Guile.  The
> +'.in' files in the directory MODULES are configured with VERSION, the
> +'.in' files in the directory SCRIPTS are configured with the bootstrap
> +Guile and its module and object directories, and the Scheme files in the
> +directory MODULES are compiled and installed."
> +  `(modify-phases %standard-phases
> +     (replace 'configure

Should this be factorized out in a (guix build gnu-bootstrap) module or
similar?  That would keep build-side code separate and would avoid
making ‘commencement.scm’ bigger.

I guess the only thing that remains to be done is changing the temporary
URLs to the self-extracting script & co., right?

Thanks a lot!

Ludo’.