Suggestion: catch repo = pname usage

[hughobrien]

Arising from a discussion here

repo = pname is nice for DRY but probably creates a binding that goes too far.

I suggest detecting when repo is anything other than a string literal.

Thanks for this project!

[drupol]

I fully agree with this.

I'm going to use this issue as a justification for people asking why they can't use a variable for the repo attribute.

The reason is that changing the pname of a derivation shouldn't change the src attribute.

Bad

stdenv.mkDerivation (finalAttrs: {
  pname = "foobar";

  src = fetchFromGitHub {
    owner = "xxx";
    repo = finalAttrs.pname;
    rev = "zzz";
    hash = "sha256-abcd";
  };
})

Good

stdenv.mkDerivation (finalAttrs: {
  pname = "foobar";

  src = fetchFromGitHub {
    owner = "xxx";
    repo = "foobar";
    rev = "zzz";
    hash = "sha256-abcd";
  };
})

[SuperSandro2000]

Especially more concerning is finalAttrs.pname