From fc1a7750a7e904743a2b5dd508095a33baf01cd5 Mon Sep 17 00:00:00 2001
From: Matt Broadstone <mbroadst@mongodb.com>
Date: Wed, 5 Feb 2020 18:01:25 -0500
Subject: [PATCH] refactor: errors before handshake should mark server unknown

---
 lib/core/sdam/server.js | 37 ++++++++++++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 5 deletions(-)

diff --git a/lib/core/sdam/server.js b/lib/core/sdam/server.js
index d60082a525..1c4aeeda79 100644
--- a/lib/core/sdam/server.js
+++ b/lib/core/sdam/server.js
@@ -279,7 +279,11 @@ class Server extends EventEmitter {
     }
 
     this.s.pool.withConnection((err, conn, cb) => {
-      if (err) return cb(err);
+      if (err) {
+        markServerUnknown(this, err);
+        return cb(err);
+      }
+
       conn.command(ns, cmd, options, makeOperationHandler(this, options, cb));
     }, callback);
   }
@@ -299,7 +303,11 @@ class Server extends EventEmitter {
     }
 
     this.s.pool.withConnection((err, conn, cb) => {
-      if (err) return cb(err);
+      if (err) {
+        markServerUnknown(this, err);
+        return cb(err);
+      }
+
       conn.query(ns, cmd, cursorState, options, makeOperationHandler(this, options, cb));
     }, callback);
   }
@@ -319,7 +327,11 @@ class Server extends EventEmitter {
     }
 
     this.s.pool.withConnection((err, conn, cb) => {
-      if (err) return cb(err);
+      if (err) {
+        markServerUnknown(this, err);
+        return cb(err);
+      }
+
       conn.getMore(ns, cursorState, batchSize, options, makeOperationHandler(this, options, cb));
     }, callback);
   }
@@ -341,7 +353,11 @@ class Server extends EventEmitter {
     }
 
     this.s.pool.withConnection((err, conn, cb) => {
-      if (err) return cb(err);
+      if (err) {
+        markServerUnknown(this, err);
+        return cb(err);
+      }
+
       conn.killCursors(ns, cursorState, makeOperationHandler(this, null, cb));
     }, callback);
   }
@@ -436,11 +452,22 @@ function executeWriteOperation(args, options, callback) {
   }
 
   server.s.pool.withConnection((err, conn, cb) => {
-    if (err) return cb(err);
+    if (err) {
+      markServerUnknown(server, err);
+      return cb(err);
+    }
+
     conn[op](ns, ops, options, makeOperationHandler(server, options, cb));
   }, callback);
 }
 
+function markServerUnknown(server, error) {
+  server.emit(
+    'descriptionReceived',
+    new ServerDescription(server.description.address, null, { error })
+  );
+}
+
 function makeOperationHandler(server, options, callback) {
   return function handleOperationResult(err, result) {
     if (err) {