concretizer: handle variants defined through validators

Variant of this kind don't have a list of possible
values encoded in the ASP facts. Since all we have
is a validator the list of possible values just includes
just the default value and possibly the value passed
from packages.yaml or cli.

lib/spack/spack/solver/asp.py

@@ -1486,6 +1486,21 @@ def setup(self, driver, specs):
                 else:
                     for clause in self.spec_clauses(dep):
                         self.gen.fact(clause)
+                        # TODO: This might need to be moved somewhere else.
+                        # TODO: It's needed to account for open-ended variants
+                        # TODO: validated through a function. The rationale is
+                        # TODO: that if a value is set from cli and validated
+                        # TODO: then it's also a possible value.
+                        if clause.name == 'variant_set':
+                            variant_name = clause.args[1]
+                            variant_def = dep.package.variants[variant_name]
+                            variant_def.validate_or_raise(
+                                dep.variants[variant_name],
+                                dep.package
+                            )
+                            self.gen.fact(
+                                fn.variant_possible_value(*clause.args)
+                            )
 
         self.gen.h1("Virtual Constraints")
         self.define_virtual_constraints()

lib/spack/spack/test/cmd/install.py

@@ -467,8 +467,14 @@ def test_cdash_report_concretization_error(tmpdir, mock_fetch, install_mockery,
             report_file = report_dir.join('Update.xml')
             assert report_file in report_dir.listdir()
             content = report_file.open().read()
-            assert '<UpdateReturnStatus>Conflicts in concretized spec' \
-                in content
+            assert '<UpdateReturnStatus>' in content
+            # The message is different based on using the
+            # new or the old concretizer
+            expected_messages = (
+                'Conflicts in concretized spec',
+                'does not satisfy'
+            )
+            assert any(x in content for x in expected_messages)
 
 
 @pytest.mark.disable_clean_stage_check