add a test

lib/spack/spack/test/concretize.py

@@ -1350,6 +1350,21 @@ def test_reuse_installed_packages_when_package_def_changes(
         # Structure and package hash will be different without reuse
         assert root.dag_hash() != new_root_without_reuse.dag_hash()
 
+    @pytest.mark.only_clingo("Use case not supported by the original concretizer")
+    def test_no_reuse_when_variant_condition_does_not_hold(self, mutable_database, mock_packages):
+        spack.config.set("concretizer:reuse", True)
+
+        # Install a spec which for which the `version_based` variant condition does not hold
+        old = Spec("conditional-variant-pkg @1").concretized()
+        old.package.do_install(fake=True, explicit=True)
+
+        # Then explicitly require a spec with `+version_based`, which shouldn't reuse previous spec
+        new1 = Spec("conditional-variant-pkg +version_based").concretized()
+        assert new1.satisfies("@2 +version_based")
+
+        new2 = Spec("conditional-variant-pkg +two_whens").concretized()
+        assert new2.satisfies("@2 +two_whens +version_based")
+
     @pytest.mark.only_clingo("Use case not supported by the original concretizer")
     def test_reuse_with_flags(self, mutable_database, mutable_config):
         spack.config.set("concretizer:reuse", True)