MDEV-26947 UNIQUE column checks fail in InnoDB resulting in table corruption

InnoDB fails to rollback the bulk insert buffered operation when
trx_mark_sql_stat_end() encounters the DB_DUPLICATE_KEY error.
In this case, check table fails with secondary index row count
mismatch. InnoDB gives the error "ER_ERROR_DURING_COMMIT"
while encountering the DB_DUPLICATE_KEY in trx_mark_sql_stat_end()

mysql-test/suite/innodb/r/insert_into_empty.result

@@ -182,3 +182,32 @@ CREATE TABLE t (i INT) ENGINE=InnoDB PARTITION BY HASH (i) PARTITIONS 2;
 INSERT INTO t VALUES (0);
 INSERT INTO t VALUES (1),(0),(1);
 DROP TABLE t;
+#
+# MDEV-26947 UNIQUE column checks fail in InnoDB resulting
+#	in table corruption
+#
+CREATE TABLE t (c1 INT KEY,c2 INT UNIQUE) ENGINE=InnoDB;
+BEGIN;
+INSERT INTO t VALUES (1,0),(2,0);
+ERROR HY000: Got error 1 "Operation not permitted" during COMMIT
+CHECK TABLE t;
+Table	Op	Msg_type	Msg_text
+test.t	check	status	OK
+COMMIT;
+DROP TABLE t;
+CREATE TABLE t (i INT UNIQUE)ENGINE=InnoDB;
+INSERT INTO t VALUES (0),(0);
+ERROR HY000: Got error 1 "Operation not permitted" during COMMIT
+CHECK TABLE t;
+Table	Op	Msg_type	Msg_text
+test.t	check	status	OK
+DROP TABLE t;
+CREATE TABLE t (c INT PRIMARY KEY,c2 CHAR(1) UNIQUE)ENGINE=InnoDB;
+BEGIN;
+INSERT INTO t VALUES(1, ''),(2, '');
+ERROR HY000: Got error 1 "Operation not permitted" during COMMIT
+SELECT * FROM t;
+c	c2
+DELETE FROM t;
+COMMIT;
+DROP TABLE t;

mysql-test/suite/innodb/t/insert_into_empty.test

@@ -193,3 +193,31 @@ CREATE TABLE t (i INT) ENGINE=InnoDB PARTITION BY HASH (i) PARTITIONS 2;
 INSERT INTO t VALUES (0);
 INSERT INTO t VALUES (1),(0),(1);
 DROP TABLE t;
+
+--echo #
+--echo # MDEV-26947 UNIQUE column checks fail in InnoDB resulting
+--echo #	in table corruption
+--echo #
+
+CREATE TABLE t (c1 INT KEY,c2 INT UNIQUE) ENGINE=InnoDB;
+BEGIN;
+--error ER_ERROR_DURING_COMMIT
+INSERT INTO t VALUES (1,0),(2,0);
+CHECK TABLE t;
+COMMIT;
+DROP TABLE t;
+
+CREATE TABLE t (i INT UNIQUE)ENGINE=InnoDB;
+--error ER_ERROR_DURING_COMMIT
+INSERT INTO t VALUES (0),(0);
+CHECK TABLE t;
+DROP TABLE t;
+
+CREATE TABLE t (c INT PRIMARY KEY,c2 CHAR(1) UNIQUE)ENGINE=InnoDB;
+BEGIN;
+--error ER_ERROR_DURING_COMMIT
+INSERT INTO t VALUES(1, ''),(2, '');
+SELECT * FROM t;
+DELETE FROM t;
+COMMIT;
+DROP TABLE t;

storage/innobase/handler/ha_innodb.cc

@@ -4547,6 +4547,10 @@ innobase_commit(
 		SQL statement */
 
 		trx_mark_sql_stat_end(trx);
+		if (UNIV_UNLIKELY(trx->error_state != DB_SUCCESS)) {
+			trx_rollback_for_mysql(trx);
+			DBUG_RETURN(1);
+		}
 	}
 
 	/* Reset the number AUTO-INC rows required */