core/pkgs/build-support/testers/test-equal-derivation.nix
2024-05-13 11:34:52 -04:00

27 lines
720 B
Nix

{ lib, runCommand, emptyFile, nix-diff }:
assertion: a: b:
let
drvA = builtins.unsafeDiscardOutputDependency a.drvPath or (throw "testEqualDerivation second argument must be a package");
drvB = builtins.unsafeDiscardOutputDependency b.drvPath or (throw "testEqualDerivation third argument must be a package");
name =
if a?name
then "testEqualDerivation-${a.name}"
else "testEqualDerivation";
in
if drvA == drvB then
emptyFile
else
runCommand name
{
inherit assertion drvA drvB;
nativeBuildInputs = [ nix-diff ];
} ''
echo "$assertion"
echo "However, the derivations differ:"
echo
echo nix-diff $drvA $drvB
nix-diff $drvA $drvB
exit 1
''