Describe the bug

In Nix 2.13, the NIX_PATH environment variable overrides the value of the nix-path setting in nix.conf.

Steps To Reproduce

E.g. if nix.conf contains

extra-nix-path = nixpkgs=flake:nixpkgs

then Nix 2.13 behaves as follows:

# NIX_PATH=nixpkgs=flake:foo nix-build  '<nixpkgs>' -A hello
error: cannot find flake 'flake:foo' in the flake registries

But on current master, NIX_PATH is ignored:

# NIX_PATH=nixpkgs=flake:foo nix-build  '<nixpkgs>' -A hello
/nix/store/7j2sjbdbhlyda1sm0s6p0frfy0dxj67i-hello-2.12.1

Expected behavior

NIX_PATH should take precedence. Not only is that what most people would expect (I think), but it's also a regression.

nix-env --version output

Additional context

This is probably caused by 1cba598.

Priorities

Add 👍 to issues you find important.