From 20d5a9cf814d3a22310d162b67762569e231d772 Mon Sep 17 00:00:00 2001
From: Shane Harvey <shane.harvey@mongodb.com>
Date: Mon, 1 Mar 2021 14:09:27 -0800
Subject: [PATCH] PYTHON-2543 Do not mark a server unknown from a "writeErrors"
 response (#570)

---
 pymongo/topology.py                           |  6 +-
 .../errors/write_errors_ignored.json          | 96 +++++++++++++++++++
 test/test_discovery_and_monitoring.py         |  4 +-
 3 files changed, 104 insertions(+), 2 deletions(-)
 create mode 100644 test/discovery_and_monitoring/errors/write_errors_ignored.json

diff --git a/pymongo/topology.py b/pymongo/topology.py
index 194884a75..4e07db86b 100644
--- a/pymongo/topology.py
+++ b/pymongo/topology.py
@@ -32,7 +32,8 @@ from pymongo.errors import (ConnectionFailure,
                             NotMasterError,
                             OperationFailure,
                             PyMongoError,
-                            ServerSelectionTimeoutError)
+                            ServerSelectionTimeoutError,
+                            WriteError)
 from pymongo.monitor import SrvMonitor
 from pymongo.pool import PoolOptions
 from pymongo.server import Server
@@ -578,6 +579,9 @@ class Topology(object):
             # operation fails because of any network error besides a socket
             # timeout...."
             return
+        elif issubclass(exc_type, WriteError):
+            # Ignore writeErrors.
+            return
         elif issubclass(exc_type, NotMasterError):
             # As per the SDAM spec if:
             #   - the server sees a "not master" error, and
diff --git a/test/discovery_and_monitoring/errors/write_errors_ignored.json b/test/discovery_and_monitoring/errors/write_errors_ignored.json
new file mode 100644
index 000000000..6b80673c1
--- /dev/null
+++ b/test/discovery_and_monitoring/errors/write_errors_ignored.json
@@ -0,0 +1,96 @@
+{
+  "description": "writeErrors field is ignored",
+  "uri": "mongodb://a/?replicaSet=rs",
+  "phases": [
+    {
+      "description": "Primary A is discovered",
+      "responses": [
+        [
+          "a:27017",
+          {
+            "ok": 1,
+            "ismaster": true,
+            "hosts": [
+              "a:27017"
+            ],
+            "setName": "rs",
+            "minWireVersion": 0,
+            "maxWireVersion": 9,
+            "topologyVersion": {
+              "processId": {
+                "$oid": "000000000000000000000001"
+              },
+              "counter": {
+                "$numberLong": "1"
+              }
+            }
+          }
+        ]
+      ],
+      "outcome": {
+        "servers": {
+          "a:27017": {
+            "type": "RSPrimary",
+            "setName": "rs",
+            "topologyVersion": {
+              "processId": {
+                "$oid": "000000000000000000000001"
+              },
+              "counter": {
+                "$numberLong": "1"
+              }
+            },
+            "pool": {
+              "generation": 0
+            }
+          }
+        },
+        "topologyType": "ReplicaSetWithPrimary",
+        "logicalSessionTimeoutMinutes": null,
+        "setName": "rs"
+      }
+    },
+    {
+      "description": "Ignore command error with writeErrors field",
+      "applicationErrors": [
+        {
+          "address": "a:27017",
+          "when": "afterHandshakeCompletes",
+          "maxWireVersion": 9,
+          "type": "command",
+          "response": {
+            "ok": 1,
+            "writeErrors": [
+              {
+                "errmsg": "NotMasterNoSlaveOk",
+                "code": 13435
+              }
+            ]
+          }
+        }
+      ],
+      "outcome": {
+        "servers": {
+          "a:27017": {
+            "type": "RSPrimary",
+            "setName": "rs",
+            "topologyVersion": {
+              "processId": {
+                "$oid": "000000000000000000000001"
+              },
+              "counter": {
+                "$numberLong": "1"
+              }
+            },
+            "pool": {
+              "generation": 0
+            }
+          }
+        },
+        "topologyType": "ReplicaSetWithPrimary",
+        "logicalSessionTimeoutMinutes": null,
+        "setName": "rs"
+      }
+    }
+  ]
+}
diff --git a/test/test_discovery_and_monitoring.py b/test/test_discovery_and_monitoring.py
index ddb87271a..4ffffffae 100644
--- a/test/test_discovery_and_monitoring.py
+++ b/test/test_discovery_and_monitoring.py
@@ -29,7 +29,8 @@ from pymongo.errors import (AutoReconnect,
                             NetworkTimeout,
                             NotMasterError,
                             OperationFailure)
-from pymongo.helpers import _check_command_response
+from pymongo.helpers import (_check_command_response,
+                             _check_write_command_response)
 from pymongo.ismaster import IsMaster
 from pymongo.server_description import ServerDescription, SERVER_TYPE
 from pymongo.settings import TopologySettings
@@ -94,6 +95,7 @@ def got_app_error(topology, app_error):
     try:
         if error_type == 'command':
             _check_command_response(app_error['response'], max_wire_version)
+            _check_write_command_response(app_error['response'])
         elif error_type == 'network':
             raise AutoReconnect('mock non-timeout network error')
         elif error_type == 'timeout':