Re: reproducible builds and debugging information

[ludo@gnu.org (Ludovic Courtès)]

Mark H Weaver <mhw@netris.org> skribis:

> I think what Tomáš suggested above does not conflict with the design of
> Nix and Guix.  As I understand it, he's suggesting that we have
> 'outputs' default to '("out" "debug") but then the debug outputs would
> be immediately discarded for most packages.  This would save both disk
> space and slave->hydra bandwidth.  Users could then get the debug
> outputs by building the package locally.

OK, I see.  The thing is that “immediately discarded” really means
“after the build completed and they’ve been put in store.”  So the build
machine would still need to be able to cope with the additional storage
requirements.

Also, currently I don’t see how we could avoid transferring the “debug”
output back to the master: when the daemon offloads a derivation build,
it really expects to be able to get all the outputs back.  We could hack
the daemon to special-case “debug” outputs but that doesn’t seem great.

Dunno, maybe I’m still too blinded by what’s possible now to think about
what could be made possible.  :-)

Thanks,
Ludo’.