MDEV-11071: Assertion `thd->transaction.stmt.is_empty()' failed in Lo…

…cked_tables_list::unlock_locked_table

fix_length_and_dec now return result (error/OK)

mysql-test/r/alter_table.result

@@ -2369,5 +2369,16 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 #
+# MDEV-11071: Assertion `thd->transaction.stmt.is_empty()' failed
+# in Locked_tables_list::unlock_locked_tables
+#
+CREATE TABLE t1 (d DATETIME DEFAULT CURRENT_TIMESTAMP, i INT) ENGINE=InnoDB;
+INSERT INTO t1 (i) VALUES (1),(1);
+LOCK TABLE t1 WRITE;
+ALTER TABLE t1 ADD UNIQUE(i);
+ERROR 23000: Duplicate entry '1' for key 'i'
+UNLOCK TABLES;
+DROP TABLE t1;
+#
 # End of 10.2 tests
 #

mysql-test/t/alter_table.test

@@ -1931,6 +1931,22 @@ alter table t1 change b new_b int not null, add column b char(1), add constraint
 show create table t1;
 drop table t1;
 
+--echo #
+--echo # MDEV-11071: Assertion `thd->transaction.stmt.is_empty()' failed
+--echo # in Locked_tables_list::unlock_locked_tables
+--echo #
+
+CREATE TABLE t1 (d DATETIME DEFAULT CURRENT_TIMESTAMP, i INT) ENGINE=InnoDB;
+INSERT INTO t1 (i) VALUES (1),(1);
+LOCK TABLE t1 WRITE;
+--error ER_DUP_ENTRY
+ALTER TABLE t1 ADD UNIQUE(i);
+
+# Cleanup
+UNLOCK TABLES;
+DROP TABLE t1;
+
+
 --echo #
 --echo # End of 10.2 tests
 --echo #

sql/item.h

@@ -4211,7 +4211,7 @@ class Item_func_or_sum: public Item_result_field,
     also to make printing of items inherited from Item_sum uniform.
   */
   virtual const char *func_name() const= 0;
-  virtual void fix_length_and_dec()= 0;
+  virtual bool fix_length_and_dec()= 0;
   bool const_item() const { return const_item_cache; }
   table_map used_tables() const { return used_tables_cache; }
   Item* build_clone(THD *thd, MEM_ROOT *mem_root);