spec.py: fix comparison with multivalued variants (spack#47485)

Author: haampie

lib/spack/spack/test/spec_semantics.py

@@ -1975,3 +1975,7 @@ def test_equality_discriminate_on_propagation(lhs, rhs):
     s, t = Spec(lhs), Spec(rhs)
     assert s != t
     assert len({s, t}) == 2
+
+
+def test_comparison_multivalued_variants():
+    assert Spec("x=a") < Spec("x=a,b") < Spec("x==a,b") < Spec("x==a,b,c")

lib/spack/spack/variant.py

@@ -378,8 +378,8 @@ def _value_setter(self, value: ValueType) -> None:
 
     def _cmp_iter(self) -> Iterable:
         yield self.name
-        yield from (str(v) for v in self.value_as_tuple)
         yield self.propagate
+        yield from (str(v) for v in self.value_as_tuple)
 
     def copy(self) -> "AbstractVariant":
         """Returns an instance of a variant equivalent to self