JAVA-2566: Include empty cursor document in AggregateToCollectionOperation when connected to a 3.6 MongoDB server

Author: jyemin

driver-core/src/main/com/mongodb/operation/AggregateToCollectionOperation.java

@@ -42,6 +42,7 @@
 import static com.mongodb.operation.OperationHelper.AsyncCallableWithConnection;
 import static com.mongodb.operation.OperationHelper.CallableWithConnection;
 import static com.mongodb.operation.OperationHelper.LOGGER;
+import static com.mongodb.operation.OperationHelper.serverIsAtLeastVersionThreeDotSix;
 import static com.mongodb.operation.OperationHelper.validateCollation;
 import static com.mongodb.operation.OperationHelper.releasingCallback;
 import static com.mongodb.operation.OperationHelper.serverIsAtLeastVersionThreeDotTwo;
@@ -270,6 +271,11 @@ private BsonDocument getCommand(final ConnectionDescription description) {
         if (bypassDocumentValidation != null && serverIsAtLeastVersionThreeDotTwo(description)) {
             commandDocument.put("bypassDocumentValidation", BsonBoolean.valueOf(bypassDocumentValidation));
         }
+
+        if (serverIsAtLeastVersionThreeDotSix(description)) {
+            commandDocument.put("cursor", new BsonDocument());
+        }
+
         appendWriteConcernToCommand(writeConcern, commandDocument, description);
         if (collation != null) {
             commandDocument.put("collation", collation.asDocument());

driver-core/src/main/com/mongodb/operation/OperationHelper.java

@@ -385,6 +385,10 @@ static boolean serverIsAtLeastVersionThreeDotFour(final ConnectionDescription de
         return serverIsAtLeastVersion(description, new ServerVersion(3, 4));
     }
 
+    static boolean serverIsAtLeastVersionThreeDotSix(final ConnectionDescription description) {
+        return serverIsAtLeastVersion(description, new ServerVersion(3, 5));
+    }
+
     static boolean serverIsAtLeastVersion(final ConnectionDescription description, final ServerVersion serverVersion) {
         return description.getServerVersion().compareTo(serverVersion) >= 0;
     }

driver-core/src/test/functional/com/mongodb/operation/AggregateToCollectionOperationSpecification.groovy

@@ -233,18 +233,23 @@ class AggregateToCollectionOperationSpecification extends OperationFunctionalSpe
             operation.collation(defaultCollation)
             expectedCommand.append('collation', defaultCollation.asDocument())
         }
+        if (useCursor) {
+            expectedCommand.append('cursor', new BsonDocument())
+        }
 
         then:
         testOperation(operation, serverVersion, expectedCommand, false, BsonDocument.parse('{ok: 1}'))
 
         where:
-        serverVersion | includeBypassValidation | includeWriteConcern | includeCollation | async
-        [3, 4, 0]     | true                    | true                | true             | true
-        [3, 4, 0]     | true                    | true                | true             | false
-        [3, 2, 0]     | true                    | false               | false            | true
-        [3, 2, 0]     | true                    | false               | false            | false
-        [3, 0, 0]     | false                   | false               | false            | true
-        [3, 0, 0]     | false                   | false               | false            | false
+        serverVersion | includeBypassValidation | includeWriteConcern | includeCollation | async  | useCursor
+        [3, 6, 0]     | true                    | true                | true             | true   | true
+        [3, 6, 0]     | true                    | true                | true             | false  | true
+        [3, 4, 0]     | true                    | true                | true             | true   | false
+        [3, 4, 0]     | true                    | true                | true             | false  | false
+        [3, 2, 0]     | true                    | false               | false            | true   | false
+        [3, 2, 0]     | true                    | false               | false            | false  | false
+        [3, 0, 0]     | false                   | false               | false            | true   | false
+        [3, 0, 0]     | false                   | false               | false            | false  | false
 
     }