refactor: ensure selected server in retry supports retryable reads

Author: mbroadst

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);