[Nix-dev] nix rebuilds

[Harmen]

I'm building a few ruby and node projects with nix. It works well enough, but
nix does too many rebuilds, also when nothing changed. The question is: how I
can figure out why it does a rebuild? Maybe some checksum has changed, but can
I somehow figure out which one?

I put the .nix file in the repo next to the code, so I don't refer to an
external repo with a nice checksum, but like this:

  src = ./.;


This is for a Ruby on Rails project build with bundix.

Any thoughts? Thanks!
Harmen