Re: reproducibility

[ludo@gnu.org (Ludovic Courtès)]

Federico Beffa <beffa@ieee.org> skribis:

> On Sun, Jan 10, 2016 at 9:49 PM, Ludovic Courtès <ludo@gnu.org> wrote:
>> Federico Beffa <beffa@ieee.org> skribis:
>>
>>> I've noticed that a derivation is a function of the order of the
>>> inputs. As an example, the following two input orders give rise to two
>>> distinct derivations:
>>>
>>> A)
>>>
>>>     (inputs
>>>      `(("texlive" ,texlive)
>>>        ("texinfo" ,texinfo)
>>>        ("m4" ,m4)
>>>        ("libx11" ,libx11))
>>>
>>> B)
>>>     (inputs
>>>      `(("texinfo" ,texinfo)
>>>        ("texlive" ,texlive)
>>>        ("m4" ,m4)
>>>        ("libx11" ,libx11))
>>>
>>> Is this intentional?
>>
>> Yes.  There are several places where order matters, most importantly
>> search paths, and these are computed from the input lists.
>
> If order matters, it would probably be more robust to force internally
> a specific order rather than relying on the (often random) order
> defined in a package recipe (possibly created by an importer, ...).

Most of the time any order would work, but I can imagine situations
where the packager could purposefully choose a specific order.  So I’d
rather not do any automatic sorting, if that’s what you have in mind.

Thanks,
Ludo’.