From b57e6e281fb8920606e134c6f2255d8f5ebbd743 Mon Sep 17 00:00:00 2001
From: Shane Harvey <shnhrv@gmail.com>
Date: Tue, 26 Jun 2018 13:59:02 -0400
Subject: [PATCH] PYTHON-1599 Fix unchecked return value in cmessagemodule

---
 pymongo/_cmessagemodule.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pymongo/_cmessagemodule.c b/pymongo/_cmessagemodule.c
index 9d358c864..29c4a7451 100644
--- a/pymongo/_cmessagemodule.c
+++ b/pymongo/_cmessagemodule.c
@@ -1199,6 +1199,10 @@ _batched_op_msg(
     }
     /* Save space for size */
     size_location = buffer_save_space(buffer, 4);
+    if (size_location == -1) {
+        PyErr_NoMemory();
+        return 0;
+    }
 
     switch (op) {
     case _INSERT: