From 3913eaa6e87d0be0b4d35b5fc44cad51cdd9e696 Mon Sep 17 00:00:00 2001
From: Matt Broadstone <mbroadst@mongodb.com>
Date: Mon, 15 Jul 2019 10:06:08 -0400
Subject: [PATCH] refactor: ensure selected server in retry supports retryable
 reads

---
 lib/operations/execute_operation.js | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/operations/execute_operation.js b/lib/operations/execute_operation.js
index 84a53a5967..6c574a6ceb 100644
--- a/lib/operations/execute_operation.js
+++ b/lib/operations/execute_operation.js
@@ -94,6 +94,10 @@ function executeOperation(topology, operation, callback) {
   });
 }
 
+function supportsRetryableReads(server) {
+  return maxWireVersion(server) >= 6;
+}
+
 function executeWithServerSelection(topology, operation, callback) {
   const readPreference = operation.readPreference || ReadPreference.primary;
 
@@ -108,7 +112,7 @@ function executeWithServerSelection(topology, operation, callback) {
 
     // select a new server, and attempt to retry the operation
     topology.selectServer(readPreference, (err, server) => {
-      if (err) {
+      if (err || !supportsRetryableReads(server)) {
         callback(err, null);
         return;
       }
@@ -127,7 +131,7 @@ function executeWithServerSelection(topology, operation, callback) {
     const shouldRetryReads =
       topology.s.options.retryReads !== false &&
       (operation.session && !operation.session.inTransaction()) &&
-      maxWireVersion(server) >= 6;
+      supportsRetryableReads(server);
 
     if (operation.hasAspect(Aspect.RETRYABLE) && shouldRetryReads) {
       operation.execute(server, callbackWithRetry);