2 files changed, 22 insertions, 13 deletions
diff --git a/lib/spack/spack/solver/concretize.lp b/lib/spack/spack/solver/concretize.lp
index 92ba77ad82..26c7907759 100644
--- a/lib/spack/spack/solver/concretize.lp
+++ b/lib/spack/spack/solver/concretize.lp
@@ -696,15 +696,18 @@ requirement_group_satisfied(node(ID, Package), X) :-
 % flags if their only source is from a requirement. This is overly-specific
 % and should use a more-generic approach like in https://github.com/spack/spack/pull/37180
 
-{ attr("node_flag", node(ID, A1), A2, A3) } :-
-  requirement_group_member(Y, Package, X),
-  activate_requirement(node(ID, Package), X),
-  imposed_constraint(Y,"node_flag_set", A1, A2, A3).
-
-{ attr("node_flag_source", node(ID, A1), A2, node(ID, A3)) } :-
-  requirement_group_member(Y, Package, X),
-  activate_requirement(node(ID, Package), X),
-  imposed_constraint(Y,"node_flag_source", A1, A2, A3).
+{ attr("node_flag", node(ID, Package), FlagType, FlagValue) } :-
+  requirement_group_member(ConditionID, Package, RequirementID),
+  activate_requirement(node(ID, Package), RequirementID),
+  pkg_fact(Package, condition_effect(ConditionID, EffectID)),
+  imposed_constraint(EffectID, "node_flag_set", Package, FlagType, FlagValue).
+
+{ attr("node_flag_source", node(NodeID1, Package1), FlagType, node(NodeID2, Package2)) } :-
+  requirement_group_member(ConditionID, Package1, RequirementID),
+  activate_requirement(node(NodeID1, Package1), RequirementID),
+  pkg_fact(Package1, condition_effect(ConditionID, EffectID)),
+  imposed_constraint(EffectID, "node_flag_source", Package1, FlagType, Package2),
+  imposed_packages(NodeID2, Package2).
 
 requirement_weight(node(ID, Package), Group, W) :-
   W = #min {
diff --git a/lib/spack/spack/test/concretize_requirements.py b/lib/spack/spack/test/concretize_requirements.py
index cd51006088..d5295691ce 100644
--- a/lib/spack/spack/test/concretize_requirements.py
+++ b/lib/spack/spack/test/concretize_requirements.py
@@ -469,16 +469,22 @@ packages:
 
 
 @pytest.mark.regression("34241")
-def test_require_cflags(concretize_scope, test_repo):
+def test_require_cflags(concretize_scope, mock_packages):
     """Ensures that flags can be required from configuration."""
     conf_str = """\
 packages:
-  y:
+  mpich2:
     require: cflags="-g"
+  mpi:
+    require: mpich cflags="-O1"
 """
     update_packages_config(conf_str)
-    spec = Spec("y").concretized()
-    assert spec.satisfies("cflags=-g")
+
+    spec_mpich2 = Spec("mpich2").concretized()
+    assert spec_mpich2.satisfies("cflags=-g")
+
+    spec_mpi = Spec("mpi").concretized()
+    assert spec_mpi.satisfies("mpich cflags=-O1")
 
 
 def test_requirements_for_package_that_is_not_needed(concretize_scope, test_repo):