Merge mysql.com:/usr/home/bar/mysql-4.1.b15581

into  mysql.com:/usr/home/bar/mysql-5.0

mysql-test/r/ctype_utf8.result

@@ -1167,3 +1167,11 @@ set @a:=null;
 execute my_stmt using @a;
 a	b
 drop table if exists t1;
+CREATE TABLE t1 (t TINYTEXT CHARACTER SET utf8);
+INSERT INTO t1 VALUES(REPEAT('a', 100));
+CREATE TEMPORARY TABLE t2 SELECT COALESCE(t) AS bug FROM t1;
+SELECT LENGTH(bug) FROM t2;
+LENGTH(bug)
+100
+DROP TABLE t2;
+DROP TABLE t1;

mysql-test/t/ctype_utf8.test

@@ -868,6 +868,16 @@ set names utf8;
 select distinct char(a) from t1;
 drop table t1;
 
+#
+# Bug#15581: COALESCE function truncates mutli-byte TINYTEXT values
+#
+CREATE TABLE t1 (t TINYTEXT CHARACTER SET utf8);
+INSERT INTO t1 VALUES(REPEAT('a', 100));
+CREATE TEMPORARY TABLE t2 SELECT COALESCE(t) AS bug FROM t1;
+SELECT LENGTH(bug) FROM t2;
+DROP TABLE t2;
+DROP TABLE t1;
+
 # End of 4.1 tests
 
 #

sql/field.cc

@@ -8981,11 +8981,11 @@ uint32 Field_blob::max_length()
   switch (packlength)
   {
   case 1:
-    return 255;
+    return 255 * field_charset->mbmaxlen;
   case 2:
-    return 65535;
+    return 65535 * field_charset->mbmaxlen;
   case 3:
-    return 16777215;
+    return 16777215 * field_charset->mbmaxlen;
   case 4:
     return (uint32) 4294967295U;
   default: