concretizer: don't optimize emitting version_satisfies() (#20128)

When all versions were allowed a version_satisfies rule was not emitted,
and this caused conditional directives to fail.

lib/spack/spack/solver/asp.py

@@ -1394,10 +1394,6 @@ def define_version_constraints(self):
             if exact_match:
                 allowed_versions = exact_match
 
-            # don't bother restricting anything if all versions are allowed
-            if len(allowed_versions) == len(self.possible_versions[pkg_name]):
-                continue
-
             predicates = [fn.version(pkg_name, v) for v in allowed_versions]
 
             # version_satisfies(pkg, constraint) is true if and only if a

lib/spack/spack/test/concretize.py

@@ -501,6 +501,11 @@ def test_conflicts_in_spec(self, conflict_spec):
         with pytest.raises(spack.error.SpackError):
             s.concretize()
 
+    def test_conflict_in_all_directives_true(self):
+        s = Spec('when-directives-true')
+        with pytest.raises(spack.error.SpackError):
+            s.concretize()
+
     @pytest.mark.parametrize('spec_str', [
         'conflict@10.0%clang+foo'
     ])