CDRIVER-3293 unpin on transient txn error

Author: kevinAlbs

src/libmongoc/src/mongoc/mongoc-client-session.c

@@ -637,6 +637,15 @@ _mongoc_client_session_handle_reply (mongoc_client_session_t *session,
       return;
    }
 
+   if (mongoc_error_has_label (reply, "TransientTransactionError")) {
+      /* Transaction Spec: "Drivers MUST unpin a ClientSession when a command
+       * within a transaction, including commitTransaction and abortTransaction,
+       * fails with a TransientTransactionError". If the server reply included
+       * a TransientTransactionError, we unpin here. If a network error caused
+       * us to add a label client-side, we unpin in network_error_reply. */
+      session->server_id = 0;
+   }
+
    while (bson_iter_next (&iter)) {
       if (!strcmp (bson_iter_key (&iter), "$clusterTime") &&
           BSON_ITER_HOLDS_DOCUMENT (&iter)) {

src/libmongoc/src/mongoc/mongoc-cluster.c

@@ -2779,19 +2779,27 @@ network_error_reply (bson_t *reply, mongoc_cmd_t *cmd)
 {
    bson_t labels;
 
-   if (!reply) {
-      return;
+   if (reply) {
+      bson_init (reply);
    }
-
-   bson_init (reply);
-
    /* Transactions Spec defines TransientTransactionError: "Any
     * network error or server selection error encountered running any
     * command besides commitTransaction in a transaction. In the case
     * of command errors, the server adds the label; in the case of
     * network errors or server selection errors where the client
     * receives no server reply, the client adds the label." */
    if (_mongoc_client_session_in_txn (cmd->session) && !cmd->is_txn_finish) {
+      /* Transaction Spec: "Drivers MUST unpin a ClientSession when a command
+       * within a transaction, including commitTransaction and abortTransaction,
+       * fails with a TransientTransactionError". If we're about to add
+       * a TransientTransactionError label due to a client side error then we
+       * unpin. If commitTransaction/abortTransation includes a label in the
+       * server reply, we unpin in _mongoc_client_session_handle_reply. */
+      cmd->session->server_id = 0;
+      if (!reply) {
+         return;
+      }
+
       BSON_APPEND_ARRAY_BEGIN (reply, "errorLabels", &labels);
       BSON_APPEND_UTF8 (&labels, "0", TRANSIENT_TXN_ERR);
       bson_append_array_end (reply, &labels);

src/libmongoc/tests/json/transactions/mongos-recovery-token.json

@@ -268,7 +268,6 @@
     },
     {
       "description": "commitTransaction retry fails on new mongos",
-      "skipReason": "currently failing",
       "useMultipleMongoses": true,
       "clientOptions": {
         "heartbeatFrequencyMS": 30000

src/libmongoc/tests/json/transactions/pin-mongos.json

@@ -827,7 +827,7 @@
     },
     {
       "description": "remain pinned after non-transient error on commit",
-      "skipReason": "currently failing",
+      "skipReason": "blocked on SPEC-1320",
       "useMultipleMongoses": true,
       "operations": [
         {
@@ -1072,7 +1072,6 @@
     },
     {
       "description": "unpin after transient error within a transaction and commit",
-      "skipReason": "currently failing",
       "useMultipleMongoses": true,
       "clientOptions": {
         "heartbeatFrequencyMS": 30000

src/libmongoc/tests/test-mongoc-transactions.c

@@ -68,20 +68,29 @@ _disable_failpoints (json_test_ctx_t *ctx, const char *host_str)
       ctx->test_framework_uri, host_str);
 
    /* Some transactions tests have a failCommand for "isMaster" repeat seven
-    * times.
-    * Repeat this seven times. */
+    * times. Repeat this seven times. And set a reduced server selection timeout
+    * so we don't hang on failed ismaster commands. */
+   mongoc_uri_set_option_as_int32 (
+      uri, MONGOC_URI_SERVERSELECTIONTIMEOUTMS, 500);
+
    for (i = 0; i < 7; i++) {
-      client = mongoc_client_new_from_uri (uri);
+      bool ret;
 
-      ASSERT_OR_PRINT (
-         mongoc_client_command_simple (
-            client,
-            "admin",
-            tmp_bson ("{'configureFailPoint': 'failCommand', 'mode': 'off'}"),
-            NULL,
-            NULL,
-            &error),
-         error);
+      client = mongoc_client_new_from_uri (uri);
+      ret = mongoc_client_command_simple (
+         client,
+         "admin",
+         tmp_bson ("{'configureFailPoint': 'failCommand', 'mode': 'off'}"),
+         NULL,
+         NULL,
+         &error);
+      if (!ret) {
+         /* Tests that fail with isMaster also fail to disable the failpoint
+          * (since we run isMaster when opening the connection). Ignore those
+          * errors. */
+         BSON_ASSERT (NULL !=
+                      strstr (error.message, "No suitable servers found"));
+      }
       mongoc_client_destroy (client);
    }
    mongoc_uri_destroy (uri);