Add error labels to MongoWriteConcernException (#834)

The error labels are at the top level of the response
document, and the code was assuming that they were
embedded in the writeConcernError document.  This fix
ensures that error labels at the top level are properly
added to MongoWriteConcernException

JAVA-4419

Author: jyemin

driver-core/src/main/com/mongodb/internal/operation/FindAndModifyHelper.java

@@ -23,6 +23,7 @@
 import com.mongodb.internal.connection.Connection;
 import com.mongodb.internal.operation.CommandOperationHelper.CommandWriteTransformer;
 import com.mongodb.internal.operation.CommandOperationHelper.CommandWriteTransformerAsync;
+import org.bson.BsonArray;
 import org.bson.BsonBoolean;
 import org.bson.BsonDocument;
 import org.bson.BsonInt32;
@@ -54,9 +55,12 @@ public T apply(final BsonDocument result, final AsyncConnection connection) {
 
     private static <T> T transformDocument(final BsonDocument result, final ServerAddress serverAddress) {
         if (hasWriteConcernError(result)) {
-            throw new MongoWriteConcernException(
+            MongoWriteConcernException writeConcernException = new MongoWriteConcernException(
                     createWriteConcernError(result.getDocument("writeConcernError")),
                     createWriteConcernResult(result.getDocument("lastErrorObject", new BsonDocument())), serverAddress);
+            result.getArray("errorLabels", new BsonArray()).stream().map(i -> i.asString().getValue())
+                    .forEach(writeConcernException::addLabel);
+            throw writeConcernException;
         }
 
         if (!result.isDocument("value")) {

driver-core/src/main/com/mongodb/internal/operation/WriteConcernHelper.java

@@ -61,9 +61,12 @@ public static boolean hasWriteConcernError(final BsonDocument result) {
     }
 
     public static MongoWriteConcernException createWriteConcernException(final BsonDocument result, final ServerAddress serverAddress) {
-        return new MongoWriteConcernException(
+        MongoWriteConcernException writeConcernException = new MongoWriteConcernException(
                 createWriteConcernError(result.getDocument("writeConcernError")),
                 WriteConcernResult.acknowledged(0, false, null), serverAddress);
+        result.getArray("errorLabels", new BsonArray()).stream().map(i -> i.asString().getValue())
+                .forEach(writeConcernException::addLabel);
+        return writeConcernException;
     }
 
     public static WriteConcernError createWriteConcernError(final BsonDocument writeConcernErrorDocument) {