diff --git a/core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java b/core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java
index 227edc23d7d..85367723c54 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java
@@ -473,9 +473,7 @@ final class DocumentParser {
             if (update != null) {
                 context.addDynamicMapper(update);
             }
-            if (fieldMapper.copyTo() != null) {
-                parseCopyFields(context, fieldMapper.copyTo().copyToFields());
-            }
+            parseCopyFields(context, fieldMapper.copyTo().copyToFields());
         }
     }
 
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java b/core/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
index b8c958f41f3..c2af9f715dd 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
@@ -43,6 +43,7 @@ import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.stream.StreamSupport;
 
 public abstract class FieldMapper extends Mapper implements Cloneable {
@@ -60,7 +61,7 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
         protected boolean indexOptionsSet = false;
         protected boolean docValuesSet = false;
         protected final MultiFields.Builder multiFieldsBuilder;
-        protected CopyTo copyTo;
+        protected CopyTo copyTo = CopyTo.empty();
 
         protected Builder(String name, MappedFieldType fieldType, MappedFieldType defaultFieldType) {
             super(name);
@@ -256,7 +257,7 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
         defaultFieldType.freeze();
         this.defaultFieldType = defaultFieldType;
         this.multiFields = multiFields;
-        this.copyTo = copyTo;
+        this.copyTo = Objects.requireNonNull(copyTo);
     }
 
     @Override
@@ -407,10 +408,7 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
         }
 
         multiFields.toXContent(builder, params);
-
-        if (copyTo != null) {
-            copyTo.toXContent(builder, params);
-        }
+        copyTo.toXContent(builder, params);
     }
 
     protected final void doXContentAnalyzers(XContentBuilder builder, boolean includeDefaults) throws IOException {
@@ -617,6 +615,12 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
      */
     public static class CopyTo {
 
+        private static final CopyTo EMPTY = new CopyTo(Collections.emptyList());
+
+        public static CopyTo empty() {
+            return EMPTY;
+        }
+
         private final List<String> copyToFields;
 
         private CopyTo(List<String> copyToFields) {
@@ -643,6 +647,9 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
             }
 
             public CopyTo build() {
+                if (copyToBuilders.isEmpty()) {
+                    return EMPTY;
+                }
                 return new CopyTo(Collections.unmodifiableList(copyToBuilders));
             }
         }
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/MetadataFieldMapper.java b/core/src/main/java/org/elasticsearch/index/mapper/MetadataFieldMapper.java
index ec84631e041..0833e8f33f3 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/MetadataFieldMapper.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/MetadataFieldMapper.java
@@ -55,7 +55,7 @@ public abstract class MetadataFieldMapper extends FieldMapper {
     }
 
     protected MetadataFieldMapper(String simpleName, MappedFieldType fieldType, MappedFieldType defaultFieldType, Settings indexSettings) {
-        super(simpleName, fieldType, defaultFieldType, indexSettings, MultiFields.empty(), null);
+        super(simpleName, fieldType, defaultFieldType, indexSettings, MultiFields.empty(), CopyTo.empty());
     }
 
     /**
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/DocumentFieldMapperTests.java b/core/src/test/java/org/elasticsearch/index/mapper/DocumentFieldMapperTests.java
index 27b90801ecc..398708d75f9 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/DocumentFieldMapperTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/DocumentFieldMapperTests.java
@@ -95,7 +95,7 @@ public class DocumentFieldMapperTests extends LuceneTestCase {
         private static final Settings SETTINGS = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT).build();
 
         FakeFieldMapper(String simpleName, MappedFieldType fieldType) {
-            super(simpleName, fieldType.clone(), fieldType.clone(), SETTINGS, null, null);
+            super(simpleName, fieldType.clone(), fieldType.clone(), SETTINGS, MultiFields.empty(), CopyTo.empty());
         }
 
         @Override
diff --git a/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/MetaJoinFieldMapper.java b/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/MetaJoinFieldMapper.java
index db9fae9b47d..2b02f41636b 100644
--- a/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/MetaJoinFieldMapper.java
+++ b/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/MetaJoinFieldMapper.java
@@ -108,7 +108,7 @@ public class MetaJoinFieldMapper extends FieldMapper {
     }
 
     MetaJoinFieldMapper(String name, MappedFieldType fieldType, Settings indexSettings) {
-        super(name, fieldType, ParentIdFieldMapper.Defaults.FIELD_TYPE, indexSettings, MultiFields.empty(), null);
+        super(name, fieldType, ParentIdFieldMapper.Defaults.FIELD_TYPE, indexSettings, MultiFields.empty(), CopyTo.empty());
     }
 
     void setFieldMapper(ParentJoinFieldMapper mapper) {
diff --git a/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentIdFieldMapper.java b/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentIdFieldMapper.java
index cc2815c373a..91adfc5fdf9 100644
--- a/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentIdFieldMapper.java
+++ b/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentIdFieldMapper.java
@@ -134,7 +134,7 @@ public final class ParentIdFieldMapper extends FieldMapper {
                                   Set<String> children,
                                   MappedFieldType fieldType,
                                   Settings indexSettings) {
-        super(simpleName, fieldType, Defaults.FIELD_TYPE, indexSettings, MultiFields.empty(), null);
+        super(simpleName, fieldType, Defaults.FIELD_TYPE, indexSettings, MultiFields.empty(), CopyTo.empty());
         this.parentName = parentName;
         this.children = children;
     }
diff --git a/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentJoinFieldMapper.java b/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentJoinFieldMapper.java
index 0b3a3885fab..7a17d9ed7fe 100644
--- a/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentJoinFieldMapper.java
+++ b/modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentJoinFieldMapper.java
@@ -249,7 +249,7 @@ public final class ParentJoinFieldMapper extends FieldMapper {
                                     MetaJoinFieldMapper uniqueFieldMapper,
                                     List<ParentIdFieldMapper> parentIdFields,
                                     boolean eagerGlobalOrdinals) {
-        super(simpleName, fieldType, Defaults.FIELD_TYPE, indexSettings, MultiFields.empty(), null);
+        super(simpleName, fieldType, Defaults.FIELD_TYPE, indexSettings, MultiFields.empty(), CopyTo.empty());
         this.parentIdFields = parentIdFields;
         this.uniqueFieldMapper = uniqueFieldMapper;
         this.uniqueFieldMapper.setFieldMapper(this);