CDRIVER-879 preserve scanner node on disconnect

Author: ajdavis

src/mongoc/mongoc-cluster.c

@@ -1079,7 +1079,7 @@ mongoc_cluster_disconnect_node (mongoc_cluster_t *cluster, uint32_t server_id)
 
       /* might never actually have connected */
       if (scanner_node && scanner_node->stream) {
-         mongoc_topology_scanner_node_destroy (scanner_node, true);
+         mongoc_topology_scanner_node_disconnect (scanner_node, true);
          EXIT;
       }
       EXIT;

src/mongoc/mongoc-topology-scanner-private.h

@@ -100,6 +100,10 @@ mongoc_topology_scanner_add_and_scan (mongoc_topology_scanner_t *ts,
 void
 mongoc_topology_scanner_node_retire (mongoc_topology_scanner_node_t *node);
 
+void
+mongoc_topology_scanner_node_disconnect (mongoc_topology_scanner_node_t *node,
+                                         bool failed);
+
 void
 mongoc_topology_scanner_node_destroy (mongoc_topology_scanner_node_t *node,
                                       bool failed);

src/mongoc/mongoc-topology-scanner.c

@@ -149,10 +149,9 @@ mongoc_topology_scanner_node_retire (mongoc_topology_scanner_node_t *node)
 }
 
 void
-mongoc_topology_scanner_node_destroy (mongoc_topology_scanner_node_t *node, bool failed)
+mongoc_topology_scanner_node_disconnect (mongoc_topology_scanner_node_t *node,
+                                         bool failed)
 {
-   DL_DELETE (node->ts->nodes, node);
-
    if (node->dns_results) {
       freeaddrinfo (node->dns_results);
       node->dns_results = NULL;
@@ -161,6 +160,7 @@ mongoc_topology_scanner_node_destroy (mongoc_topology_scanner_node_t *node, bool
 
    if (node->cmd) {
       mongoc_async_cmd_destroy (node->cmd);
+      node->cmd = NULL;
    }
 
    if (node->stream) {
@@ -169,8 +169,16 @@ mongoc_topology_scanner_node_destroy (mongoc_topology_scanner_node_t *node, bool
       } else {
          mongoc_stream_destroy (node->stream);
       }
+
+      node->stream = NULL;
    }
+}
 
+void
+mongoc_topology_scanner_node_destroy (mongoc_topology_scanner_node_t *node, bool failed)
+{
+   DL_DELETE (node->ts->nodes, node);
+   mongoc_topology_scanner_node_disconnect (node, failed);
    bson_free (node);
 }