From f8c375e550ac6851bec534475c781dee2e112aaa Mon Sep 17 00:00:00 2001
From: lma <lma@cloudera.com>
Date: Fri, 8 Mar 2019 11:12:04 -0800
Subject: [PATCH] ATLAS-2933:Empty array attributes are returned as null
 instead of an empty list.

---
 .../store/graph/v2/AtlasGraphUtilsV2.java     | 13 +++---
 .../store/graph/v2/EntityGraphRetriever.java  |  6 ++-
 .../graph/v2/AtlasComplexAttributesTest.java  | 42 ++++++++++++++++++-
 3 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/repository/src/main/java/org/apache/atlas/repository/store/graph/v2/AtlasGraphUtilsV2.java b/repository/src/main/java/org/apache/atlas/repository/store/graph/v2/AtlasGraphUtilsV2.java
index 8f4baa1cc9c..b144bf9f372 100644
--- a/repository/src/main/java/org/apache/atlas/repository/store/graph/v2/AtlasGraphUtilsV2.java
+++ b/repository/src/main/java/org/apache/atlas/repository/store/graph/v2/AtlasGraphUtilsV2.java
@@ -207,12 +207,15 @@ public static <T extends AtlasElement> void setProperty(T element, String proper
         Object existingValue = element.getProperty(propertyName, Object.class);
 
         if (value == null || (value instanceof Collection && ((Collection)value).isEmpty())) {
-            if (existingValue != null) {
-                if (LOG.isDebugEnabled()) {
-                    LOG.debug("Removing property {} from {}", propertyName, toString(element));
+            if (value == null) {
+                if (existingValue != null) {
+                    if (LOG.isDebugEnabled()) {
+                        LOG.debug("Removing property {} from {}", propertyName, toString(element));
+                    }
+                    element.removeProperty(propertyName);
                 }
-
-                element.removeProperty(propertyName);
+            } else {
+                element.setProperty(propertyName, value);
             }
         } else {
             if (!value.equals(existingValue)) {
diff --git a/repository/src/main/java/org/apache/atlas/repository/store/graph/v2/EntityGraphRetriever.java b/repository/src/main/java/org/apache/atlas/repository/store/graph/v2/EntityGraphRetriever.java
index c727a4fd937..fc69357c828 100644
--- a/repository/src/main/java/org/apache/atlas/repository/store/graph/v2/EntityGraphRetriever.java
+++ b/repository/src/main/java/org/apache/atlas/repository/store/graph/v2/EntityGraphRetriever.java
@@ -725,6 +725,10 @@ private List<AtlasObjectId> mapVertexToArrayForSoftRef(AtlasVertex entityVertex,
         List<AtlasObjectId> ret        = null;
         List                softRefVal = entityVertex.getListProperty(attribute.getVertexPropertyName(), List.class);
 
+        if (CollectionUtils.isEmpty(softRefVal)) {
+            return softRefVal;
+        }
+
         if (CollectionUtils.isNotEmpty(softRefVal)) {
             ret = new ArrayList<>();
 
@@ -822,7 +826,7 @@ private List<Object> mapVertexToArray(AtlasVertex entityVertex, AtlasEntityExtIn
         List<Object>   arrayElements    = getArrayElementsProperty(arrayElementType, entityVertex, attribute);
 
         if (CollectionUtils.isEmpty(arrayElements)) {
-            return null;
+            return arrayElements;
         }
 
         if (LOG.isDebugEnabled()) {
diff --git a/repository/src/test/java/org/apache/atlas/repository/store/graph/v2/AtlasComplexAttributesTest.java b/repository/src/test/java/org/apache/atlas/repository/store/graph/v2/AtlasComplexAttributesTest.java
index cf7fa080a6c..2a3624a13a2 100644
--- a/repository/src/test/java/org/apache/atlas/repository/store/graph/v2/AtlasComplexAttributesTest.java
+++ b/repository/src/test/java/org/apache/atlas/repository/store/graph/v2/AtlasComplexAttributesTest.java
@@ -38,6 +38,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -48,10 +49,13 @@
 import static org.apache.atlas.TestUtilsV2.ENTITY_TYPE_MAP;
 import static org.apache.atlas.TestUtilsV2.ENTITY_TYPE_WITH_COMPLEX_COLLECTION_ATTR;
 import static org.apache.atlas.TestUtilsV2.ENTITY_TYPE_WITH_COMPLEX_COLLECTION_ATTR_DELETE;
+import static org.apache.atlas.TestUtilsV2.ENTITY_TYPE_WITH_NESTED_COLLECTION_ATTR;
 import static org.apache.atlas.TestUtilsV2.NAME;
 import static org.apache.atlas.repository.graph.GraphHelper.getStatus;
 import static org.apache.atlas.type.AtlasTypeUtil.getAtlasObjectId;
 import static org.testng.Assert.assertNull;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.assertTrue;
 import static org.testng.AssertJUnit.assertEquals;
 
 @Guice(modules = TestModules.TestOnlyModule.class)
@@ -59,6 +63,7 @@ public class AtlasComplexAttributesTest extends AtlasEntityTestBase {
     private AtlasEntityWithExtInfo complexCollectionAttrEntity;
     private AtlasEntityWithExtInfo complexCollectionAttrEntityForDelete;
     private AtlasEntityWithExtInfo mapAttributesEntity;
+    private AtlasEntityWithExtInfo nestedCollectionAttrEntity;
 
     @BeforeClass
     public void setUp() throws Exception {
@@ -66,13 +71,15 @@ public void setUp() throws Exception {
 
         // create typeDefs
         AtlasTypesDef[] testTypesDefs = new AtlasTypesDef[] { TestUtilsV2.defineTypeWithComplexCollectionAttributes(),
-                                                              TestUtilsV2.defineTypeWithMapAttributes() };
+                                                              TestUtilsV2.defineTypeWithMapAttributes(),
+                                                              TestUtilsV2.defineTypeWithNestedCollectionAttributes()};
         createTypesDef(testTypesDefs);
 
         // create entity
         complexCollectionAttrEntity          = TestUtilsV2.createComplexCollectionAttrEntity();
         complexCollectionAttrEntityForDelete = TestUtilsV2.createComplexCollectionAttrEntity();
         mapAttributesEntity                  = TestUtilsV2.createMapAttrEntity();
+        nestedCollectionAttrEntity           = TestUtilsV2.createNestedCollectionAttrEntity();
     }
 
     @Test
@@ -195,6 +202,39 @@ private void updateEntityMapAttributes(AtlasEntity attrEntity, Map<String, Strin
         attrEntity.setAttribute("mapAttr5", map5);
     }
 
+    @Test
+    public void testEmptyArrayAttribute() throws Exception {
+        init();
+        AtlasEntity nestedEntity = nestedCollectionAttrEntity.getEntity();
+
+        // set the attribute - arrayOfArrayOfStrings of the nestedEntity to
+        // an empty list. Expected behavior is that retrieved entity will
+        // have the value of this field as an empty list instead of null.
+        nestedEntity.setAttribute("arrayOfArrayOfStrings", Collections.emptyList());
+        AtlasEntitiesWithExtInfo nestedEntitiesInfo = new AtlasEntitiesWithExtInfo(nestedEntity);
+
+        EntityMutationResponse response       = entityStore.createOrUpdate(new AtlasEntityStream(nestedEntitiesInfo), false);
+        AtlasEntityHeader updatedNestedEntity = response.getFirstCreatedEntityByTypeName(ENTITY_TYPE_WITH_NESTED_COLLECTION_ATTR);
+        validateEntity(nestedEntitiesInfo, getEntityFromStore(updatedNestedEntity));
+    }
+
+    @Test(dependsOnMethods = "testCreateComplexAttributeEntity")
+    public void testNullArrayAttribute() throws Exception {
+        init();
+
+        // set the attribute - listOfStructs of the complexEntity to null.
+        // Expected behavior is that the retrieved entity will
+        // not have the attribute of listOfStructs.
+        AtlasEntity complexEntity = getEntityFromStore(complexCollectionAttrEntity.getEntity().getGuid());
+        assertTrue(complexEntity.getAttributes().containsKey("listOfStructs"));
+
+        complexEntity.setAttribute("listOfStructs", null);
+        AtlasEntitiesWithExtInfo complexEntityInfo = new AtlasEntitiesWithExtInfo(complexEntity);
+        EntityMutationResponse responseUpdated     = entityStore.createOrUpdate(new AtlasEntityStream(complexEntityInfo), false);
+        AtlasEntityHeader updatedComplexEntity     = responseUpdated.getFirstUpdatedEntityByTypeName(ENTITY_TYPE_WITH_COMPLEX_COLLECTION_ATTR);
+        assertFalse(updatedComplexEntity.getAttributes().containsKey("listOfStructs"));
+    }
+
     @Test(dependsOnMethods = "testCreateComplexAttributeEntity")
     public void testStructArray() throws Exception {
         init();