Normalize SingleTypeRelationshipImportResult on creation

Author: s1ck

core/src/main/java/org/neo4j/gds/api/RelationshipPropertyStore.java

@@ -19,7 +19,6 @@
  */
 package org.neo4j.gds.api;
 
-import org.immutables.value.Value;
 import org.neo4j.gds.annotation.ValueClass;
 
 import java.util.Collection;
@@ -32,6 +31,10 @@ public interface RelationshipPropertyStore {
 
     Map<String, RelationshipProperty> relationshipProperties();
 
+    default boolean isEmpty() {
+        return relationshipProperties().isEmpty();
+    }
+
     default RelationshipProperty get(String propertyKey) {
         return relationshipProperties().get(propertyKey);
     }
@@ -48,13 +51,6 @@ default boolean containsKey(String propertyKey) {
         return relationshipProperties().containsKey(propertyKey);
     }
 
-    @Value.Check
-    default void validate() {
-        if (relationshipProperties().isEmpty()) {
-            throw new IllegalStateException("Relationship property store must not be empty.");
-        }
-    }
-
     static Builder builder() {
         // need to initialize with empty map due to `deferCollectionAllocation = true`
         return new Builder().relationshipProperties(Collections.emptyMap());

core/src/main/java/org/neo4j/gds/core/loading/SingleTypeRelationshipImportResult.java

@@ -19,6 +19,7 @@
  */
 package org.neo4j.gds.core.loading;
 
+import org.immutables.value.Value;
 import org.neo4j.gds.annotation.ValueClass;
 import org.neo4j.gds.api.RelationshipPropertyStore;
 import org.neo4j.gds.api.Relationships;
@@ -42,6 +43,17 @@ public interface SingleTypeRelationshipImportResult {
 
     Optional<RelationshipPropertyStore> inverseProperties();
 
+    @Value.Check
+    default SingleTypeRelationshipImportResult normalize() {
+        if (properties().map(RelationshipPropertyStore::isEmpty).orElse(false)) {
+            return builder().from(this).properties(Optional.empty()).build();
+        }
+        if (inverseProperties().map(RelationshipPropertyStore::isEmpty).orElse(false)) {
+            return builder().from(this).inverseProperties(Optional.empty()).build();
+        }
+        return this;
+    }
+
     static ImmutableSingleTypeRelationshipImportResult.Builder builder() {
         return ImmutableSingleTypeRelationshipImportResult.builder();
     }