CDRIVER-696: If the server description knows the last error, use it

Author: bjori

src/mongoc/mongoc-cluster.c

@@ -1171,10 +1171,14 @@ _mongoc_cluster_add_node (mongoc_cluster_t *cluster,
                                                        sd->id);
 
       if (!scanner_node) {
-         bson_set_error (error,
-                         MONGOC_ERROR_STREAM,
-                         MONGOC_ERROR_STREAM_NOT_ESTABLISHED,
-                         "Could not find node %s", sd->connection_address);
+         if (sd->error.code) {
+            memcpy (error, &sd->error, sizeof *error);
+         } else {
+            bson_set_error (error,
+                            MONGOC_ERROR_STREAM,
+                            MONGOC_ERROR_STREAM_NOT_ESTABLISHED,
+                            "Could not find node %s", sd->connection_address);
+         }
          RETURN (NULL);
       }
 
@@ -1363,10 +1367,15 @@ mongoc_cluster_fetch_stream (mongoc_cluster_t *cluster,
 
       scanner_node = mongoc_topology_scanner_get_node (topology->scanner, server_id);
       if (!scanner_node) {
-         bson_set_error (error,
-                         MONGOC_ERROR_STREAM,
-                         MONGOC_ERROR_STREAM_NOT_ESTABLISHED,
-                         "Could not find node %u", server_id);
+         sd = mongoc_topology_description_server_by_id (&topology->description, server_id);
+         if (sd && sd->error.code) {
+            memcpy (error, &sd->error, sizeof *error);
+         } else {
+            bson_set_error (error,
+                            MONGOC_ERROR_STREAM,
+                            MONGOC_ERROR_STREAM_NOT_ESTABLISHED,
+                            "Could not find node %u", server_id);
+         }
          GOTO(FETCH_FAIL);
       }
 
@@ -1396,7 +1405,8 @@ mongoc_cluster_fetch_stream (mongoc_cluster_t *cluster,
 
          /* In single-threaded mode, we can use sd's max_wire_version */
          if (!_mongoc_cluster_auth_node (cluster, stream, sd->host.host,
-                                         sd->max_wire_version, error)) {
+                                         sd->max_wire_version, &sd->error)) {
+            memcpy (error, &sd->error, sizeof *error);
             GOTO(FETCH_FAIL);
          }
          scanner_node->has_auth = true;