Previously, unless unsupported platforms were allowed, the following
would fail to evaluate (from an "x86_64-linux" system):
pkgsCross.x86_64-freebsd.__splicedPackages.docutils.__spliced.buildHost
It shouldn't have, because the buildHost package ends up being for
Linux. This broke evaluation of e.g. pkgsCross.x86_64-freebsd.libdrm,
because it has docutils in nativeBuildInputs. mkDerivation would try
to go through __spliced.buildHost on docutils to get to the Linux
version, but the check in ensurePythonModules would kick in first,
triggering the meta check because of the equality check in the
implementation of hasPythonModule, which would fail because Python is
not marked as supported on FreeBSD in Nixpkgs at the moment. Thus,
even though they're not supposed to be, the meta checks would be
triggered even though the only attribute being accessed on the
unsupported derivation was __spliced.
We can fix this by using the same mechanism used to implement the meta
checks themselves: lib.extendDerivation. Now, attempting to access
drvPath or outPath on an attribute that fails the validity check will
produce the same error as before, but other accesses will be allowed
through, fixing splicing.
I've tested evaluation of packages that pass and fail the validity
check, and confirmed that the behaviour is still correct.
It wasn't clear before, but it turns out that this is just four
separate conditions, and an attribute is valid if any of the
conditions is true, so we don't need a sea of parentheses to express
it.
checkInputs used to be added to nativeBuildInputs. Now we have
nativeCheckInputs to do that instead. Doing this treewide change allows
to keep hashes identical to before the introduction of
nativeCheckInputs.
fetchPypi doesn't use python under the hood and doesn't need to be tied
to a specific version of python. Moving it to top level makes it more
consistent with other fetchers and makes code generation easier.
- Remove code related to i686 archs (not supported anymore since #209100)
- Split non-install steps in installPhase in installCheckPhase/preFixup
- Add missing pre/post hooks
