Bug/452

nemo/src/execution/planning/operations/negation.rs

@@ -28,6 +28,7 @@ pub(crate) fn node_negation(
         .iter()
         .map(|atom| {
             let subtract_markers = variable_translation.operation_table(atom.terms().iter());
+
             let node = subplan_union(
                 plan,
                 table_manager,
@@ -36,9 +37,22 @@ pub(crate) fn node_negation(
                 subtract_markers.clone(),
             );
 
-            // We simply apply all constraints to this node
-            // Constraints which do not reference this atom will be filtered in the physical layer
-            let node_filtered = node_filter(plan, variable_translation, node, subtracted_filters);
+            // We only keep those constraints that can be evaluated within the current atom
+            let filters = subtracted_filters
+                .iter()
+                .filter(|filter| {
+                    filter.variables().all(|variable| {
+                        subtract_markers.contains(
+                            variable_translation
+                                .get(variable)
+                                .expect("variable translation must know every variable"),
+                        )
+                    })
+                })
+                .cloned()
+                .collect::<Vec<Constraint>>();
+
+            let node_filtered = node_filter(plan, variable_translation, node, &filters);
 
             // The tables may contain columns that are not part of `node_main`.
             // These need to be projected away.

nemo/src/execution/planning/plan_head_restricted.rs

@@ -80,8 +80,6 @@ impl RestrictedChaseStrategy {
         let head_join_atoms = analysis.existential_aux_rule.positive_body().clone();
         let head_join_constraints = analysis.existential_aux_rule.positive_constraints().clone();
 
-        println!("{:?}, {:?}", head_join_atoms, head_join_constraints);
-
         let aux_head = &analysis.existential_aux_rule.head()[0];
         let mut aux_head_order = VariableOrder::new();
         let mut used_join_head_variables = HashSet::<Variable>::new();

resources/testcases/regression/planning_engine/constants_negation/run.rls

@@ -0,0 +1,21 @@
+%%% Test related to 
+%%% https://github.com/knowsys/nemo/issues/452
+%%%
+%%% Previously, an incorrect plan was produced, which lead to a crash. 
+
+S(a, b, c).
+S(r, r, r).
+T(a, b).
+T(a, c).
+
+R(?x, ?y, ?z) :- 
+    S(?x, ?y, ?z),
+    ~ T(?x, ?y),
+    ~ T(a, ?z).
+
+R(?x, ?y, ?z) :- 
+    S(?x, ?y, ?z),
+    ~ T(a, ?y),
+    ~ T(a, ?z).
+
+@export R :- csv {} .

resources/testcases/regression/planning_engine/constants_negation/run/R.csv

@@ -0,0 +1 @@
+r,r,r