ATLAS-2325: fix to prevent duplicate elements in SET type attributes

repository/src/main/java/org/apache/atlas/repository/store/graph/v1/EntityGraphMapper.java

@@ -33,6 +33,7 @@ import org.apache.atlas.model.instance.AtlasStruct;
 import org.apache.atlas.model.instance.EntityMutationResponse;
 import org.apache.atlas.model.instance.EntityMutations.EntityOperation;
 import org.apache.atlas.model.typedef.AtlasStructDef.AtlasAttributeDef;
+import org.apache.atlas.model.typedef.AtlasStructDef.AtlasAttributeDef.Cardinality;
 import org.apache.atlas.repository.Constants;
 import org.apache.atlas.repository.RepositoryException;
 import org.apache.atlas.repository.graph.GraphHelper;
@@ -60,18 +61,19 @@ import org.springframework.stereotype.Component;
 
 import javax.inject.Inject;
 import java.util.*;
+import java.util.stream.Collectors;
 
 import static org.apache.atlas.model.instance.AtlasRelatedObjectId.KEY_RELATIONSHIP_ATTRIBUTES;
 import static org.apache.atlas.model.instance.EntityMutations.EntityOperation.CREATE;
 import static org.apache.atlas.model.instance.EntityMutations.EntityOperation.DELETE;
 import static org.apache.atlas.model.instance.EntityMutations.EntityOperation.PARTIAL_UPDATE;
 import static org.apache.atlas.model.instance.EntityMutations.EntityOperation.UPDATE;
+import static org.apache.atlas.model.typedef.AtlasStructDef.AtlasAttributeDef.Cardinality.SET;
 import static org.apache.atlas.repository.Constants.STATE_PROPERTY_KEY;
 import static org.apache.atlas.repository.graph.GraphHelper.getTypeName;
 import static org.apache.atlas.repository.graph.GraphHelper.isRelationshipEdge;
 import static org.apache.atlas.repository.graph.GraphHelper.string;
 import static org.apache.atlas.repository.store.graph.v1.AtlasGraphUtilsV1.getIdFromVertex;
-import static org.apache.atlas.type.AtlasStructType.AtlasAttribute.AtlasRelationshipEdgeDirection.BOTH;
 import static org.apache.atlas.type.AtlasStructType.AtlasAttribute.AtlasRelationshipEdgeDirection.IN;
 import static org.apache.atlas.type.AtlasStructType.AtlasAttribute.AtlasRelationshipEdgeDirection.OUT;
 
@@ -808,6 +810,7 @@ public class EntityGraphMapper {
         AtlasType      elementType         = arrType.getElementType();
         boolean        isReference         = AtlasGraphUtilsV1.isReference(elementType);
         AtlasAttribute inverseRefAttribute = attribute.getInverseRefAttribute();
+        Cardinality    cardinality         = attribute.getAttributeDef().getCardinality();
         List<Object>   newElementsCreated  = new ArrayList<>();
         List<Object>   currentElements;
 
@@ -818,6 +821,10 @@ public class EntityGraphMapper {
         }
 
         if (CollectionUtils.isNotEmpty(newElements)) {
+            if (cardinality == SET) {
+                newElements = (List) newElements.stream().distinct().collect(Collectors.toList());
+            }
+
             for (int index = 0; index < newElements.size(); index++) {
                 AtlasEdge               existingEdge = getEdgeAt(currentElements, index, elementType);
                 AttributeMutationContext arrCtx      = new AttributeMutationContext(ctx.getOp(), ctx.getReferringVertex(), ctx.getAttribute(), newElements.get(index),