Function INSERT() now works according to coercibility rules

Test for INSERT() has been added

mysql-test/r/func_str.result

@@ -303,6 +303,9 @@ latin2_general_ci	3
 select collation(substring(_latin2'ab',1)), coercibility(substring(_latin2'ab',1));
 collation(substring(_latin2'ab',1))	coercibility(substring(_latin2'ab',1))
 latin2_general_ci	3
+select collation(insert(_latin2'abcd',2,3,_latin2'ef')), coercibility(insert(_latin2'abcd',2,3,_latin2'ef'));
+collation(insert(_latin2'abcd',2,3,_latin2'ef'))	coercibility(insert(_latin2'abcd',2,3,_latin2'ef'))
+latin2_general_ci	3
 create table t1 
 select
 left(_latin2'a',1),
@@ -322,7 +325,8 @@ repeat(_latin2'a',10),
 reverse(_latin2'ab'),
 quote(_latin2'ab'),
 soundex(_latin2'ab'),
-substring(_latin2'ab',1)
+substring(_latin2'ab',1),
+insert(_latin2'abcd',2,3,_latin2'ef')
 ;
 show create table t1;
 Table	Create Table
@@ -344,6 +348,7 @@ t1	CREATE TABLE `t1` (
   `reverse(_latin2'ab')` char(2) character set latin2 NOT NULL default '',
   `quote(_latin2'ab')` char(6) character set latin2 NOT NULL default '',
   `soundex(_latin2'ab')` char(4) character set latin2 NOT NULL default '',
-  `substring(_latin2'ab',1)` char(2) character set latin2 NOT NULL default ''
+  `substring(_latin2'ab',1)` char(2) character set latin2 NOT NULL default '',
+  `insert(_latin2'abcd',2,3,_latin2'ef')` char(6) character set latin2 NOT NULL default ''
 ) TYPE=MyISAM CHARSET=latin1
 drop table t1;

mysql-test/t/func_str.test

@@ -154,6 +154,7 @@ select collation(reverse(_latin2'ab')), coercibility(reverse(_latin2'ab'));
 select collation(quote(_latin2'ab')), coercibility(quote(_latin2'ab'));
 select collation(soundex(_latin2'ab')), coercibility(soundex(_latin2'ab'));
 select collation(substring(_latin2'ab',1)), coercibility(substring(_latin2'ab',1));
+select collation(insert(_latin2'abcd',2,3,_latin2'ef')), coercibility(insert(_latin2'abcd',2,3,_latin2'ef'));
 
 create table t1 
 select
@@ -174,7 +175,8 @@ select
   reverse(_latin2'ab'),
   quote(_latin2'ab'),
   soundex(_latin2'ab'),
-  substring(_latin2'ab',1)
+  substring(_latin2'ab',1),
+  insert(_latin2'abcd',2,3,_latin2'ef')
 ;
 
 show create table t1;

sql/item_strfunc.cc

@@ -861,6 +861,14 @@ null:
 
 void Item_func_insert::fix_length_and_dec()
 {
+  if (set_charset(args[0]->charset(), args[0]->coercibility,
+      		  args[3]->charset(), args[3]->coercibility))
+  {
+      my_error(ER_CANT_AGGREGATE_COLLATIONS,MYF(0),
+	     args[0]->charset()->name,coercion_name(args[0]->coercibility),
+	     args[3]->charset()->name,coercion_name(args[3]->coercibility),
+	     func_name());
+  }
   max_length=args[0]->max_length+args[3]->max_length;
   if (max_length > MAX_BLOB_WIDTH)
   {