Re: [v2 0/1] Erlang

[ludo@gnu.org (Ludovic Courtès)]

Leo Famulari <leo@famulari.name> skribis:

> On Fri, Apr 01, 2016 at 10:19:11AM +0200, Pjotr Prins wrote:
>> 
>> On Thu, Mar 31, 2016 at 03:35:44PM -0400, Leo Famulari wrote:
>> > This adds Erlang.
>> > 
>> > Originally written by Steve Sprang, I added the man pages and fixed all
>> > the "FHS bugs" I noticed.
>> > 
>> > Pjotr used it to build a working Elixir:
>> > http://lists.gnu.org/archive/html/guix-devel/2016-03/msg00999.html
>> 
>> Better even, I am actually using that Elixir and Erlang :). Please
>> push when there are no other issues.
>  
> Cool! From my point of view, there are no blocking issues.
>
> There are two sources of non-determinism when building repeatedly on the
> same machine.
>
> All the .beam files have timestamps and build paths embedded [0]. This
> is a known issue without a clear solution. The build paths don't seem so
> bad to me, since my understanding is that they are set deterministically
> by the Guix builder.
>
> There are also some .script files that also embed timestamps in a human
> readable string. Grepping for the string makes it easy to find the
> source of this. We could patch the timestamp format string with the
> value of SOURCE_DATE_EPOCH.
>
> Thoughts?
>
> [0]
> https://wiki.debian.org/ReproducibleBuilds/TimestampsInBeamFiles

A patch along the lines of the one of the page above should do the work
for beam files, no?  We’d have to change DEB_BUILD_DATE to
SOURCE_DATE_EPOCH, and remove regexp-matching from there.

Ludo’ (who’s never written Erlang code ;-)).