fix(cypher): restore cartesian where pattern OR/XOR fail-fast (#1391)

Author: lmeyerov

graphistry/compute/gfql/cypher/lowering.py

@@ -6231,6 +6231,9 @@ def lower_match_query(
     row_where: Optional[ExpressionText] = None
     row_where_predicates: List[str] = list(dynamic_row_where_predicates)
     if query.where is not None:
+        where_expr_upper = boolean_expr_to_text(query.where.expr_tree).upper() if query.where.expr_tree is not None else ""
+        if _cartesian_node_only_patterns(merged_match) is not None and query.where.expr_tree is not None and _where_expr_tree_pattern_predicates(query.where.expr_tree) and (" OR " in where_expr_upper or " XOR " in where_expr_upper):
+            raise _unsupported_at_span("Cypher WHERE pattern predicates mixed with OR/XOR are not yet supported for cartesian MATCH patterns", field="where", value=where_expr_upper, span=query.where.span)
         where_expr, where_pattern_row_filters = _rewrite_where_expr_patterns_to_markers(
             where=query.where,
             alias_targets=alias_targets,

graphistry/tests/compute/gfql/cypher/test_lowering.py

@@ -1555,6 +1555,25 @@ def test_string_cypher_supports_cartesian_node_only_row_filter_between_aliases()
     ]
 
 
+def test_string_cypher_rejects_cartesian_where_pattern_predicates_mixed_with_or() -> None:
+    graph = _mk_graph(
+        pd.DataFrame(
+            {
+                "id": [0, 1, 2],
+                "label__TheLabel": [False, True, False],
+                "label__MissingLabel": [False, False, False],
+            }
+        ),
+        pd.DataFrame({"s": [0, 0, 1], "d": [1, 2, 2], "type": ["T", "X", "T"]}),
+    )
+    with pytest.raises(GFQLValidationError, match="OR/XOR"):
+        graph.gfql(
+            "MATCH (a), (b) "
+            "WHERE a.id = 0 AND (a)-[:T]->(b:TheLabel) OR (a)-[:T*]->(b:MissingLabel) "
+            "RETURN DISTINCT b"
+        )
+
+
 def test_string_cypher_supports_cartesian_dynamic_pattern_property_projection() -> None:
     graph = _mk_cartesian_dynamic_pattern_graph()