Avoid NPE on ElementSchema#hasProperty

Co-authored-by: Florentin Dörre <florentin.dorre@neotechnology.com>

Author: Mats-SX

core/src/test/java/org/neo4j/gds/api/schema/NodeSchemaTest.java

@@ -34,11 +34,18 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class NodeSchemaTest {
 
+    @Test
+    void handlesOutsideOfSchemaRequests() {
+        NodeSchema empty = NodeSchema.builder().build();
+        assertFalse(empty.hasProperty(NodeLabel.of("NotInSchema"), "notInSchemaEither"));
+    }
+
     @Test
     void testDefaultValues() {
         var label = NodeLabel.of("Foo");

core/src/test/java/org/neo4j/gds/api/schema/RelationshipSchemaTest.java

@@ -34,11 +34,18 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class RelationshipSchemaTest {
 
+    @Test
+    void handlesOutsideOfSchemaRequests() {
+        var empty = RelationshipSchema.builder().build();
+        assertFalse(empty.hasProperty(RelationshipType.of("NotInSchema"), "notInSchemaEither"));
+    }
+
     @Test
     void testDefaultValuesAndAggregation() {
         var relType = RelationshipType.of("BAR");

graph-schema-api/src/main/java/org/neo4j/gds/api/schema/ElementSchema.java

@@ -59,7 +59,9 @@ default boolean hasProperties(ELEMENT_IDENTIFIER elementIdentifier) {
 
     @Value.Default
     default boolean hasProperty(ELEMENT_IDENTIFIER elementIdentifier, String propertyKey) {
-        return (!properties().get(elementIdentifier).isEmpty() && properties().get(elementIdentifier).containsKey(propertyKey));
+        return properties().containsKey(elementIdentifier) && (!properties()
+            .get(elementIdentifier)
+            .isEmpty() && properties().get(elementIdentifier).containsKey(propertyKey));
     }
 
     @Value.Default