From 048ee81836fa477e4f4052bea5b8e6ae58483c48 Mon Sep 17 00:00:00 2001
From: Prashant Mital <5883388+prashantmital@users.noreply.github.com>
Date: Mon, 17 May 2021 13:58:06 -0700
Subject: [PATCH] PYTHON-2719 RawBatchCursor must raise StopIteration instead
 of returning empty bytes when the cursor contains no results (#624)

---
 pymongo/message.py  | 4 +++-
 test/test_cursor.py | 7 +++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/pymongo/message.py b/pymongo/message.py
index 25de5a72f..d08636ff1 100644
--- a/pymongo/message.py
+++ b/pymongo/message.py
@@ -1526,7 +1526,9 @@ class _OpReply(object):
                                    error_object.get("$err"),
                                    error_object.get("code"),
                                    error_object)
-        return [self.documents]
+        if self.documents:
+            return [self.documents]
+        return []
 
     def unpack_response(self, cursor_id=None,
                         codec_options=_UNICODE_REPLACE_CODEC_OPTIONS,
diff --git a/test/test_cursor.py b/test/test_cursor.py
index 582d0641e..fb657c3f6 100644
--- a/test/test_cursor.py
+++ b/test/test_cursor.py
@@ -1471,7 +1471,14 @@ class TestRawBatchCursor(IntegrationTest):
         explanation = c.find_raw_batches().explain()
         self.assertIsInstance(explanation, dict)
 
+    def test_empty(self):
+        self.db.test.drop()
+        cursor = self.db.test.find_raw_batches()
+        with self.assertRaises(StopIteration):
+            next(cursor)
+
     def test_clone(self):
+        self.db.test.insert_one({})
         cursor = self.db.test.find_raw_batches()
         # Copy of a RawBatchCursor is also a RawBatchCursor, not a Cursor.
         self.assertIsInstance(next(cursor.clone()), bytes)