[Reproducible-builds] Bug#824049: emacs24: please make start value of gensym-counter reproducible

[Alexis Bienvenüe]

Source: emacs24
Version: 24.5+1-6
Severity: wishlist
Tags: patch upstream
User: reproducible-builds at lists.alioth.debian.org
Usertags: toolchain
X-Debbugs-Cc: reproducible-builds at lists.alioth.debian.org

Dear Maintainer,

When bytecompiling elisp files, cl-gensym-counter is initialized from
the current time, leading to unreproducible results. This can affect
reproducibility [1] of some software packages that build-depend on emacs
(and of emacs24 itself). I suggest to set the initial value of
cl-gensym-counter from the names of the files to be compiled (see
proposed patch).

Test-case:

cd /tmp
wget
https://sources.debian.net/data/main/e/emacs24/24.5+1-5/lisp/org/ob-C.el
emacs -batch --no-site-file --no-site-lisp -f batch-byte-compile ob-C.el
cp ob-C.elc ob-C.elc.0
sleep 1
emacs -batch --no-site-file --no-site-lisp -f batch-byte-compile ob-C.el
diff ob-C.elc ob-C.elc.0

The two files should be the same, but they differ (with different #:Gnnn
values)

Regards,
Alexis Bienvenüe.

[1] https://wiki.debian.org/ReproducibleBuilds/

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