From 386ac12a48c7a4abcd2f82f21bcf5a48a235d7fd Mon Sep 17 00:00:00 2001
From: mkaruza <mario.karuza@galeracluster.com>
Date: Mon, 26 Jul 2021 09:14:37 +0200
Subject: [PATCH] MDEV-25740 Assertion `!wsrep_has_changes(thd) ||
 (thd->lex->sql_command == SQLCOM_CREATE_TABLE &&
 !thd->is_current_stmt_binlog_format_row())' failed in void
 wsrep_commit_empty(THD*, bool)
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Using ROLLBACK with `completion_type = CHAIN` result in start of
transaction and implicit commit before previous WSREP internal data is
cleared.

Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
---
 mysql-test/suite/galera/r/MDEV-25740.result |  9 +++++++++
 mysql-test/suite/galera/t/MDEV-25740.test   | 14 ++++++++++++++
 sql/sql_parse.cc                            |  5 +++++
 3 files changed, 28 insertions(+)
 create mode 100644 mysql-test/suite/galera/r/MDEV-25740.result
 create mode 100644 mysql-test/suite/galera/t/MDEV-25740.test

diff --git a/mysql-test/suite/galera/r/MDEV-25740.result b/mysql-test/suite/galera/r/MDEV-25740.result
new file mode 100644
index 00000000000..5a4318a7f19
--- /dev/null
+++ b/mysql-test/suite/galera/r/MDEV-25740.result
@@ -0,0 +1,9 @@
+connection node_2;
+connection node_1;
+SET AUTOCOMMIT = OFF;
+SET completion_type = CHAIN;
+CREATE TABLE t1(f1 INT) ENGINE=InnoDB;
+BEGIN;
+INSERT INTO t1 VALUES (1);
+ROLLBACK;
+DROP TABLE t1;
diff --git a/mysql-test/suite/galera/t/MDEV-25740.test b/mysql-test/suite/galera/t/MDEV-25740.test
new file mode 100644
index 00000000000..0ea8d5f55c0
--- /dev/null
+++ b/mysql-test/suite/galera/t/MDEV-25740.test
@@ -0,0 +1,14 @@
+#
+# When `completion_type = CHAIN` is used, transaction started should not have previous writeset.
+#
+
+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+
+SET AUTOCOMMIT = OFF;
+SET completion_type = CHAIN;
+CREATE TABLE t1(f1 INT) ENGINE=InnoDB;
+BEGIN;
+INSERT INTO t1 VALUES (1);
+ROLLBACK;
+DROP TABLE t1;
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 3cccca9b786..9e78a1a95e2 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -5750,6 +5750,11 @@ mysql_execute_command(THD *thd)
     /* Begin transaction with the same isolation level. */
     if (tx_chain)
     {
+#ifdef WITH_WSREP
+      /* If there are pending changes after rollback we should clear them */
+      if (wsrep_on(thd) && wsrep_has_changes(thd))
+        wsrep_after_statement(thd);
+#endif
       if (trans_begin(thd))
         goto error;
     }