[Nix-dev] garbage collection and nix-push

[Michael Raskin]

>> Of course, if you look at it you will see that you can easily generate
>> such a file yourself and nix-build it.
>
>I was looking at that just now :)
>
>But I would like to go a step further and just patch nix-push a bit.
>It doesn't need to copy anything I guess.
>Just having it output the result of building that expression to
>$destDir/result instead of to the tempdir and produce symlinks from
>$destDir into that result would save space and (copy)time and have the
>benefit of plugging into a gcroot all at once.

Note: this wouldn't work for Hydra where pushes happen to go to remote
storage some of the time, but such an option would hopefully be 
mergeable into mainline nix-push.