Without the change metadata evaluation fails on package like
`zammad.src` where no fields are defined in `.nix `files:
src = fetchFromGitHub (lib.importJSON ./source.json);
There evaluation fails as:
$ nix-instantiate --strict --eval --expr 'with import ./. {}; zammad.src.meta'
error:
23| # to indicate where derivation originates, similar to make-derivation.nix's mkDerivation
24| position = "${position.file}:${toString position.line}";
| ^
25| };
error: value is null while a set was expected
After the change evaluation succeeds as:
$ nix-instantiate --strict --eval --expr 'with import ./. {}; zammad.src.meta'
{ homepage = "https://github.com/zammad/zammad"; }
Passing a (multi-line) string was deprecated in #200082 in favour of
list of strings, but still supported (with warning). Now, enforce use of
list of strings.
a67950f20b added `url` attribute
from `fetchurl` and therefore also from `fetchzip`.
We previously relied on `url` from fetchgit-based fetchers
to find the repo URL but now it will just return tarballs
in the case of `fetchFrom{GitHub,GitLab}`.
Let’s add an attribute to `fetch{git,FromGitHub,FromGitLab}`
to expose a repo URL consistently.
