scheme and lisp

[Ludovic Courtès]

Hello Bernhard,

"Bernhard M. Wiedemann via rb-general"
<rb-general at lists.reproducible-builds.org> skribis:

> in openSUSE there are some packages that so far refuse to build
> reproducibly. The common theme around them is that they use scheme or
> lisp to produce binaries with a 'dump' command.

I think this practice is vanishing.  For one, Emacs had an ‘unexec’
function that produced an ELF executable containing an image of its heap
at the time the function was called; this was replaced by a portable and
reproducible mechanism in Emacs 27, released in August 2020.

[...]

> The list of our packages I think are affected by this is:
> clisp
> scheme48
> chezscheme
> emacs
> maxima
> scsh
> xindy
>
> Most distros seem to be affected by this:
> http://ismypackagereproducibleyet.org/?pkg=scheme48
> http://ismypackagereproducibleyet.org/?pkg=emacs surprisingly shows as
> reproducible in Archlinux, but I could not figure out why.
> maxima also shows as green there.
>
> Can we get them reproducible? Or can we drop+replace these
> implementations with guile?

Scheme implementations are all vastly different, notably because they
implement different things: the standards were historically very
minimal, so to do practical things, you had to implement custom
extensions.  Because of that, you can’t just use one “Scheme”
implementation as a drop-in replacement for another one.

The implementations are also very different: for instance, Chez
implements a native ahead-of-time compiler whereas Guile has bytecode
compilation plus just-in-time compilation.  Thus problems and solutions
for one implementation are unlikely to translate to other
implementations.

That said I’m surprised about Emacs, this needs more investigation…

HTH,
Ludo’.