MDEV-25718 Assertion `transaction.is_streaming()' failed

* Update wsrep-lib which contains the fix
* Add deterministic test case that reproduces the assertion
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

mysql-test/suite/galera_sr/r/MDEV-25718.result

+connection node_2;
+connection node_1;
+CREATE TABLE t1 (f1 INTEGER PRIMARY KEY);
+connection node_1;
+SET SESSION wsrep_trx_fragment_size = 1;
+START TRANSACTION;
+SET debug_sync = "ha_write_row_end SIGNAL write_row_end WAIT_FOR write_row_continue";
+INSERT INTO t1 VALUES (1);;
+connect node_ctrl, 127.0.0.1, root, , test, $NODE_MYPORT_1;
+connection node_ctrl;
+SET debug_sync = "now WAIT_FOR write_row_end";
+SET GLOBAL debug_dbug = '+d,wsrep_streaming_rollback';
+connect node_1a, 127.0.0.1, root, , test, $NODE_MYPORT_1;
+connection node_1a;
+TRUNCATE TABLE t1;;
+connection node_ctrl;
+SET SESSION debug_sync = "now WAIT_FOR wsrep_streaming_rollback_reached";
+SET SESSION wsrep_sync_wait = 0;
+SET debug_sync = "now SIGNAL write_row_continue";
+SET SESSION debug_sync = "now SIGNAL wsrep_streaming_rollback_continue";
+connection node_1a;
+connection node_1;
+ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
+connection node_ctrl;
+SET GLOBAL debug_dbug = "";
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t1;

mysql-test/suite/galera_sr/t/MDEV-25718.cnf

+# Set thread-handling as a workaround to avoid MDEV-26528.
+# The file can be removed once fixed.
+
+!include ../galera_2nodes.cnf
+
+[mysqld.1]
+thread-handling=pool-of-threads

mysql-test/suite/galera_sr/t/MDEV-25718.test

+#
+# MDEV-25718 Assertion `transaction.is_streaming()' failed in
+#            void wsrep::transaction::adopt()
+#
+
+--source include/galera_cluster.inc
+--source include/have_debug_sync.inc
+
+CREATE TABLE t1 (f1 INTEGER PRIMARY KEY);
+
+#
+# Start a SR transaction and block it after it has replicated
+# a fragment. Notice the transaction is still in executing state.
+#
+--connection node_1
+SET SESSION wsrep_trx_fragment_size = 1;
+START TRANSACTION;
+SET debug_sync = "ha_write_row_end SIGNAL write_row_end WAIT_FOR write_row_continue";
+--send INSERT INTO t1 VALUES (1);
+
+--connect node_ctrl, 127.0.0.1, root, , test, $NODE_MYPORT_1
+--connection node_ctrl
+SET debug_sync = "now WAIT_FOR write_row_end";
+SET GLOBAL debug_dbug = '+d,wsrep_streaming_rollback';
+
+#
+# Issue a conflicting DDL, that will block in streaming_rollback
+# sync point.
+#
+--connect node_1a, 127.0.0.1, root, , test, $NODE_MYPORT_1
+--connection node_1a
+--send TRUNCATE TABLE t1;
+
+--connection node_ctrl
+SET SESSION debug_sync = "now WAIT_FOR wsrep_streaming_rollback_reached";
+
+#
+# Let the INSERT continue. If bug is present will be able to go through
+# before_rollback() / streaming_rollback() and clear its streaming context,
+# which causes the assertion to trigger in BF aborter.
+#
+SET SESSION wsrep_sync_wait = 0;
+SET debug_sync = "now SIGNAL write_row_continue";
+
+# Let's give the INSERT some time, to make sure it does rollback
+--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE INFO = "INSERT INTO t1 VALUES (1)" AND STATE = "Freeing items";
+--source include/wait_condition.inc
+
+# Resume the DDL in streaming_rollback
+SET SESSION debug_sync = "now SIGNAL wsrep_streaming_rollback_continue";
+
+--connection node_1a
+--reap
+
+--connection node_1
+--error ER_LOCK_DEADLOCK
+--reap
+
+# Cleanup
+--connection node_ctrl
+SET GLOBAL debug_dbug = "";
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t1;

sql/wsrep_server_service.cc

@@ -32,6 +32,7 @@
 #include "sql_class.h" /* system variables */
 #include "transaction.h" /* trans_xxx */
 #include "sql_base.h" /* close_thread_tables */
+#include "debug_sync.h"
 
 static void init_service_thd(THD* thd, char* thread_stack)
 {
@@ -388,6 +389,16 @@ int Wsrep_server_service::wait_committing_transactions(int timeout)
   return wsrep_wait_committing_connections_close(timeout);
 }
 
-void Wsrep_server_service::debug_sync(const char*)
+void Wsrep_server_service::debug_sync(const char* sync_point)
 {
+  DBUG_EXECUTE_IF(sync_point, {
+      std::stringstream dbug_action;
+      dbug_action << "now "
+                  << "SIGNAL " << sync_point << "_reached "
+                  << "WAIT_FOR " << sync_point << "_continue";
+      const std::string& action(dbug_action.str());
+      DBUG_ASSERT(!debug_sync_set_action(current_thd,
+                                         action.c_str(),
+                                         action.length()));
+    };);
 }