[Nix-dev] Re: Git expression

[Isaac Dupree]

Marc Weber wrote:
> On Tue, Jun 17, 2008 at 10:29:53AM -0400, Isaac Dupree wrote:
>>  Marc Weber wrote:
>>> Ways how this could be achieved:
>>> a) rebuild 3 times removing not needed parts (expensive)
>>> b) build once, copy only the files you need to a new derviation store
>>>   path (then the not needed parts will be garbage collected)
>>> Both can lead to trouble and more time to be spend on maintainance of
>>> the packages..
>>  thinking about (b)... Debian splits packages after they've been built, so we 
>>  know that it can be done (they'll make sure of it).  The difference perhaps 
>>  is that we'd put the different parts in different prefixes.  So we really 
>>  should, for example, pass a different --docdir to ./configure than --prefix, 
>>  which "should" make things work (probably with some build-systems and even 
>>  some configure-based, there will be things that don't quite work right, so 
>>  maintenance-work can at least help upstream fix those... at least, that 
>>  philosophy towards upstream is GoboLinux's...)
> There are more differences:
> Passing different --docdir --prefix directories does not work, because
> you don't know the final destination at this point, you know them after
> the packages has been compiled because the hash for the doc and binary
> expressions will have it listed as dependency influencing their hash.

well, can you use repeated hash rewriting afterwards to fix 
dependencies?  but... if docs are something that the program (if it's a 
program) accesses, then the program has to depend on the docs, so there 
was no point separating them (unless you find some way to use a wrapper, 
I guess)

> On the other hand I don't care about the header files and I need
> documentation. So there is not that much benefit.
> you also need to list each dependency twice (buildInputs = [libXY_dv
> libXY_runtime])
> Hmm then most --find-lib-xy-in=$what_here_include_or_libs ?
> will no longer work. This could all be patched though. It just seems to
> be a lot of effort. Benefits and costs doesn't pay off for me.

well, I don't care that much either, I usually *want* those development 
files anyway (unless I'm trying to cram it into a small disk-space for 
some reason, livecd/usb maybe)

-Isaac