MDEV-24522 Assertion `inited==NONE' fails upon UPDATE on versioned table with unique blob

Cause: no table->update_handler cloned at the moment of
vers_insert_history_row(). update_handler is needed because there
can't be several inited indexes at once in the same handler. First
index is inited by QUICK_RANGE_SELECT::reset(). Then when history row
is inserted check_duplicate_long_entry_key() is done and it requires
another index.

mysql-test/suite/versioning/r/update.result

@@ -399,3 +399,19 @@ a	check_row(row_start, row_end)
 1	HISTORICAL ROW
 1	CURRENT ROW
 drop tables t1, t2, t3;
+#
+# MDEV-24522 Assertion `inited==NONE' fails upon UPDATE on versioned table with unique blob
+
+create table t1 (a int, b int, c text, unique(c), key (b)) engine=myisam with system versioning;
+insert into t1 values (1, 1, 'foo'), (2, 11, 'bar');
+update t1 set a = 3 where b <= 9;
+update t1 set a = 3 where b <= 10;
+drop table t1;
+create table t1 (a int, b int, c text, unique(c), key (b)) engine=myisam with system versioning;
+create table t2 (a int, b int, c text, unique(c), key (b)) engine=myisam with system versioning;
+insert into t1 values (1, 1, 'foo'), (2, 11, 'bar');
+insert into t2 values (1, 1, 'foo'), (2, 11, 'bar');
+update t1 set a = 3 where b <= 9;
+update t2 set a = 3 where b <= 9;
+update t1, t2 set t1.a = 3, t2.a = 3 where t1.b <= 10 and t2.b <= 10 and t1.b = t2.b;
+drop tables t1, t2;

mysql-test/suite/versioning/t/update.test

@@ -326,4 +326,28 @@ select *, check_row(row_start, row_end) from t2 for system_time all order by row
 # cleanup
 drop tables t1, t2, t3;
 
+--echo #
+--echo # MDEV-24522 Assertion `inited==NONE' fails upon UPDATE on versioned table with unique blob
+--echo
+create table t1 (a int, b int, c text, unique(c), key (b)) engine=myisam with system versioning;
+insert into t1 values (1, 1, 'foo'), (2, 11, 'bar');
+
+update t1 set a = 3 where b <= 9;
+update t1 set a = 3 where b <= 10;
+
+# cleanup
+drop table t1;
+
+create table t1 (a int, b int, c text, unique(c), key (b)) engine=myisam with system versioning;
+create table t2 (a int, b int, c text, unique(c), key (b)) engine=myisam with system versioning;
+insert into t1 values (1, 1, 'foo'), (2, 11, 'bar');
+insert into t2 values (1, 1, 'foo'), (2, 11, 'bar');
+
+update t1 set a = 3 where b <= 9;
+update t2 set a = 3 where b <= 9;
+update t1, t2 set t1.a = 3, t2.a = 3 where t1.b <= 10 and t2.b <= 10 and t1.b = t2.b;
+
+# cleanup
+drop tables t1, t2;
+
 source suite/versioning/common_finish.inc;

sql/handler.h

@@ -3191,7 +3191,7 @@ class handler :public Sql_alloc
   {
     cached_table_flags= table_flags();
   }
-  /* ha_ methods: pubilc wrappers for private virtual API */
+  /* ha_ methods: public wrappers for private virtual API */
   
   int ha_open(TABLE *table, const char *name, int mode, uint test_if_locked,
               MEM_ROOT *mem_root= 0, List<String> *partitions_to_open=NULL);

sql/sql_update.cc

@@ -1108,6 +1108,7 @@ int mysql_update(THD *thd,
       {
         store_record(table, record[2]);
         table->mark_columns_per_binlog_row_image();
+        table->clone_handler_for_update();
         error= vers_insert_history_row(table);
         restore_record(table, record[2]);
         if (unlikely(error))
@@ -2599,6 +2600,7 @@ int multi_update::send_data(List<Item> &not_used_values)
       if (has_vers_fields && table->versioned(VERS_TIMESTAMP))
       {
         store_record(table, record[2]);
+        table->clone_handler_for_update();
         if (unlikely(error= vers_insert_history_row(table)))
         {
           restore_record(table, record[2]);