Fix rel props projection

Author: IoannisPanagiotas

CHANGELOG.md

@@ -6,8 +6,9 @@
 ### Bug Fixes
 1. Fix a bug where disconnected nodes were not projected.
 2. Fix a bug where multiple nodes containing the identifying name could be nondeterministically matched. The user must now specify the exact name.
-3. Support weighted degree centrality.
-4.  Support projecting specific node labels.
+3. Support weighted degree centrality. 
+4. Support projecting specific node labels.
+5. Fix a bug where projection would fail loading non-numbers relationship properties. 
 
 ### Other Changes
 

mcp_server/src/mcp_server_neo4j_gds/gds.py

@@ -206,6 +206,8 @@ def create_projection_query(node_labels):
 
 
 def validate_rel_properties(gds: GraphDataScience, rel_properties, node_labels=None):
+    if node_labels is None:
+        node_labels = []
     if len(node_labels) > 0:
         match_rel_query = f"""
             MATCH (n)-[r]->(m)
@@ -218,17 +220,26 @@ def validate_rel_properties(gds: GraphDataScience, rel_properties, node_labels=N
     valid_rel_properties = {}
     for i in range(len(rel_properties)):
         pi = gds.run_cypher(
-            f"{match_rel_query} RETURN distinct r.{rel_properties[i]} IS :: STRING AS ISSTRING"
+            f"""
+            {match_rel_query} 
+            WITH r.{rel_properties[i]}  AS prop
+            WITH 
+            CASE 
+                WHEN prop IS :: FLOAT THEN 1
+                WHEN prop IS :: INTEGER THEN 1
+            ELSE 2
+            END AS INVALID_PROP_TYPE
+            RETURN distinct(INVALID_PROP_TYPE)
+            """
         )
-        if pi.shape[0] == 1 and bool(pi["ISSTRING"][0]) is False:
-            valid_rel_properties[rel_properties[i]] = f"r.{rel_properties[i]}"
+        if pi.shape[0] == 1 and int(pi["INVALID_PROP_TYPE"][0]) == 1:
+            valid_rel_properties[rel_properties[i]] = f"toFloat(r.{rel_properties[i]}"
     return valid_rel_properties
 
 
 def validate_node_properties(gds: GraphDataScience, node_properties, node_labels=None):
     if node_labels is None:
         node_labels = []
-
     projectable_properties = {}
 
     for i in range(len(node_properties)):
@@ -282,14 +293,14 @@ def validate_node_properties(gds: GraphDataScience, node_properties, node_labels
 
 
 def create_source_projection_properties(projectable_properties):
-    return create_projection_properties(projectable_properties, "n")
+    return create_node_projection_properties(projectable_properties, "n")
 
 
 def create_target_projection_properties(projectable_properties):
-    return create_projection_properties(projectable_properties, "m")
+    return create_node_projection_properties(projectable_properties, "m")
 
 
-def create_projection_properties(projectable_properties, variable):
+def create_node_projection_properties(projectable_properties, variable):
     valid_node_properties = {}
     for prop in projectable_properties:
         property_type = projectable_properties[prop]

mcp_server/tests/test_projection.py

@@ -141,6 +141,51 @@ def test_node_projection_properties_with_node_labels(neo4j_container):
     assert "prop" not in projection_properties_foo
 
 
+@pytest.mark.asyncio
+def test_rel_projection_properties(neo4j_container):
+    """Import test data into Neo4j."""
+    # Set environment variables for the import script
+    os.environ["NEO4J_URI"] = neo4j_container
+    os.environ["NEO4J_USERNAME"] = NEO4J_USER
+    os.environ["NEO4J_PASSWORD"] = NEO4J_PASSWORD
+
+    driver = GraphDatabase.driver(neo4j_container, auth=(NEO4J_USER, NEO4J_PASSWORD))
+    existing_count1 = -1
+    existing_count2 = -2
+    gds = GraphDataScience(driver)
+    with driver.session() as session:
+        session.run("CREATE (:Foo)-[:R{ prop_ok1: 2.0}]->(:Foo)")
+        session.run("CREATE (:Foo)-[:R{ prop_ok2: 2}]->(:Foo)")
+        session.run("CREATE (:Foo)-[:R{ prop_bad: 2.0}]->(:Foo)")
+        session.run("CREATE (:Foo)-[:R{ prop_bad: 'Foo'}]->(:Foo)")
+
+        res = session.run("MATCH (n) WHERE 'Foo' IN labels(n) RETURN count(n) as count")
+        existing_count1 = res.single()["count"]
+
+    # do validations
+    from mcp_server.src.mcp_server_neo4j_gds.gds import validate_rel_properties
+
+    projection_properties = validate_rel_properties(
+        gds, ["prop_ok1", "prop_ok2", "prop_bad"]
+    )
+
+    # remove data
+    with driver.session() as session:
+        session.run("MATCH (n:Foo)  DETACH DELETE n")
+
+        res = session.run("MATCH (n) WHERE 'Foo' IN labels(n) RETURN count(n) as count")
+        existing_count2 = res.single()["count"]
+
+    driver.close()
+
+    # assertions at the end to ensure failures do not affect other tests
+    assert existing_count1 == 8
+    assert existing_count2 == 0
+    assert "prop_ok1" in projection_properties
+    assert "prop_ok2" in projection_properties
+    assert "prop_bad" not in projection_properties
+
+
 @pytest.mark.asyncio
 def test_rel_projection_properties_with_node_labels(neo4j_container):
     """Import test data into Neo4j."""