adding verification for dynamic mapping

Author: henriquepaes1

server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java

@@ -334,14 +334,16 @@ public final void validate(MappingLookup mappers) {
             }
 
             final String sourceScope = mappers.nestedLookup().getNestedParent(this.fullPath());
+            ObjectMapper.Dynamic dynamic = mappers.getMapping().getRoot().dynamic;
+            boolean needsFieldVerification = dynamic != null && dynamic.equals(ObjectMapper.Dynamic.FALSE);
             for (String copyTo : this.copyTo().copyToFields()) {
                 if (mappers.isMultiField(copyTo)) {
                     throw new IllegalArgumentException("[copy_to] may not be used to copy to a multi-field: [" + copyTo + "]");
                 }
                 if (mappers.isObjectField(copyTo)) {
                     throw new IllegalArgumentException("Cannot copy to field [" + copyTo + "] since it is mapped as an object");
                 }
-                if (mappers.getMapper(copyTo) == null){
+                if (needsFieldVerification && mappers.getMapper(copyTo) == null){
                     throw new IllegalArgumentException("Cannot copy to field [" + copyTo + "] since it is a non existent field");
                 }
 

server/src/test/java/org/elasticsearch/index/mapper/CopyToMapperTests.java

@@ -645,18 +645,38 @@ public void testCopyFromMultiField() {
         assertThat(e.getMessage(), Matchers.containsString("[copy_to] may not be used to copy from a multi-field: [field.bar]"));
     }
 
-    public void testCopyToNonExistentField() {
-        Exception e = expectThrows(IllegalArgumentException.class, () -> createDocumentMapper(fieldMapping(b -> {
-            b.startObject("test_field");
+    public void testCopyToNonExistentFieldDynamicFalse() {
+        Exception e = expectThrows(IllegalArgumentException.class, () -> createDocumentMapper(topMapping(b -> {
+            b.field("dynamic", "false");
+            b.startObject("properties");
             {
-                b.field("type", "text");
-                b.array("copy_to", "missing_field");
+                b.startObject("test_field");
+                {
+                    b.field("type", "text");
+                    b.field("copy_to", "missing_field");
+                }
+                b.endObject();
             }
             b.endObject();
         })));
         assertThat(e.getMessage(), Matchers.containsString("Cannot copy to field [missing_field] since it is a non existent field"));
     }
 
+    public void testCopyToNonExistentFieldDynamicTrue() throws IOException {
+        DocumentMapper mapper = createDocumentMapper(topMapping(b -> {
+            b.field("dynamic", "true");
+            b.startObject("properties");
+            {
+                b.startObject("test_field");
+                {
+                    b.field("type", "text");
+                    b.field("copy_to", "missing_field");
+                }
+                b.endObject();
+            }
+            b.endObject();}));
+    }
+
     public void testCopyToDateRangeFailure() throws Exception {
         DocumentMapper docMapper = createDocumentMapper(topMapping(b -> {
             b.startObject("properties");