[Nix-dev] Debugging nixpkgs

[Michael Raskin]

>Konrad Hinsen writes:
>
> > While trying to build some derivations for MacOSX, I hit a problem
> > which I think is a bug in nixpkgs and which moreover I think I know
> > how to fix. How would I best go about debugging this? Can I just
> > copy the source code somewhere, modify some files, and then test-build
> > and test-run with that modified version? Do I risk messing up my
> > installation that way? I don't quite see yet how modifying the
> > source code of nixpkgs fits into the "nothing ever changes" view
> > of Nix.
>
>I would still like to see comments on this issue. I understand that most of you
>are working on improving nixpkgs. What's your setup? A checkout of the SVN
>source code on which you work? Do you keep different profiles for the release
>version and your personal working copy? Or is it safe to mix both in a single
>profile?

Changes to NixPkgs tree do not affect the packages built from it; and it
is version-controlled, so you can revert if you make a mistake. 

nix-call-package script allows me to test most of the new packages 
without adding them to all-packages.nix

I don't install anything in profiles; I use systemPackages for some 
things and direct "nix-build -o something " for others; obviously,
testing is done with nix-build.