The NixOS 21.03 release has been delayed to 21.05. See NixOS/rfcs#80.
There are two instances of 21.03 which have been left as is, since they
are in stateVersion comparisons. This will ensure that existing user
configurations which refer to 21.03 will continue to work.
continuation of #109595
pkgconfig was aliased in 2018, however, it remained in
all-packages.nix due to its wide usage. This cleans
up the remaining references to pkgs.pkgsconfig and
moves the entry to aliases.nix.
python3Packages.pkgconfig remained unchanged because
it's the canonical name of the upstream package
on pypi.
The current algorithm creates attributes with null values for packages
with no source in a variant of MELPA. Though will satify dependencies
they produce no files, and though a build that transitively depends on
one them will be successful, Emacs won't find them and any code
depending on them won't work.
The solution with minimal code change would have been filtering the
list of results from melpaDerivation by comparing the value against
null, but that leads to an infinite recursion.
This commit also moves legacy renames from the shared to the unstable
set, as the corresponding null value elements won't exist in the
stable set anymore.
The test used for the problem was:
$ nix-build --show-trace ./default.nix -A emacs26Packages.melpaStablePackages.findr
error: expression does not evaluate to a derivation (or a set or list of those)
The expected output, obtained with this commit is:
$ nix-build --show-trace ./default.nix -A emacs26Packages.melpaStablePackages.findr
error: attribute 'findr' in selection path 'emacs26Packages.melpaStablePackages.findr' not found
