Bug#7302: UCS2 data in ENUM field get truncated when new column is added

mysql-test/r/ctype_ucs.result

@@ -581,3 +581,14 @@ x,y	0078002C0079
 z	007A
 x,y,z,,,	0078002C0079002C007A002C00E4002C00F6002C00FC
 drop table t1;
+create table t1(a enum('a','b','c')) default character set ucs2;
+insert into t1 values('a'),('b'),('c');
+alter table t1 add b char(1);
+show warnings;
+Level	Code	Message
+select * from t1 order by a;
+a	b
+a	NULL
+b	NULL
+c	NULL
+drop table t1;

mysql-test/t/ctype_ucs.test

@@ -374,3 +374,13 @@ insert into t1 values ('x,y');
 insert into t1 values ('x,y,z,,,');
 select a, hex(a) from t1 order by a;
 drop table t1;
+
+#
+# Bug#7302 UCS2 data in ENUM fields get truncated when new column is added
+#
+create table t1(a enum('a','b','c')) default character set ucs2;
+insert into t1 values('a'),('b'),('c');
+alter table t1 add b char(1);
+show warnings;
+select * from t1 order by a;
+drop table t1;

sql/mysql_priv.h

@@ -815,6 +815,7 @@ ulonglong find_set(TYPELIB *lib, const char *x, uint length, CHARSET_INFO *cs,
 		   char **err_pos, uint *err_len, bool *set_warning);
 uint find_type(TYPELIB *lib, const char *find, uint length, bool part_match);
 uint find_type2(TYPELIB *lib, const char *find, uint length, CHARSET_INFO *cs);
+void unhex_type2(TYPELIB *lib);
 uint check_word(TYPELIB *lib, const char *val, const char *end,
 		const char **end_of_word);
 

sql/strfunc.cc

@@ -169,6 +169,43 @@ uint find_type2(TYPELIB *typelib, const char *x, uint length, CHARSET_INFO *cs)
 } /* find_type */
 
 
+/*
+  Un-hex all elements in a typelib
+
+  SYNOPSIS
+   unhex_type2()
+   interval       TYPELIB (struct of pointer to values + lengths + count)
+
+  NOTES
+
+  RETURN
+    N/A
+*/
+
+void unhex_type2(TYPELIB *interval)
+{
+  for (uint pos= 0; pos < interval->count; pos++)
+  {
+    char *from, *to;
+    for (from= to= (char*) interval->type_names[pos]; *from; )
+    {
+      /*
+        Note, hexchar_to_int(*from++) doesn't work
+        one some compilers, e.g. IRIX. Looks like a compiler
+        bug in inline functions in combination with arguments
+        that have a side effect. So, let's use from[0] and from[1]
+        and increment 'from' by two later.
+      */
+
+      *to++= (char) (hexchar_to_int(from[0]) << 4) +
+                     hexchar_to_int(from[1]);
+      from+= 2;
+    }
+    interval->type_lengths[pos] /= 2;
+  }
+}
+
+
 /*
   Check if the first word in a string is one of the ones in TYPELIB
 

sql/table.cc

@@ -490,25 +490,7 @@ int openfrm(const char *name, const char *alias, uint db_stat, uint prgflag,
     {
       /* Unescape UCS2 intervals from HEX notation */
       TYPELIB *interval= outparam->intervals + interval_nr - 1;
-      for (uint pos= 0; pos < interval->count; pos++)
-      {
-        char *from, *to;
-        for (from= to= (char*) interval->type_names[pos]; *from; )
-        {
-          /*
-            Note, hexchar_to_int(*from++) doesn't work
-            one some compilers, e.g. IRIX. Looks like a compiler
-            bug in inline functions in combination with arguments
-            that have a side effect. So, let's use from[0] and from[1]
-            and increment 'from' by two later.
-          */
-
-          *to++= (char) (hexchar_to_int(from[0]) << 4) +
-                         hexchar_to_int(from[1]);
-          from+= 2;
-        }
-        interval->type_lengths[pos] /= 2;
-      }
+      unhex_type2(interval);
     }
     
     *field_ptr=reg_field=

sql/unireg.cc

@@ -174,6 +174,17 @@ bool mysql_create_frm(THD *thd, my_string file_name,
     goto err2;
   if (my_close(file,MYF(MY_WME)))
     goto err3;
+
+  {
+    /* Unescape all UCS2 intervals: were escaped in pack_headers */
+    List_iterator<create_field> it(create_fields);
+    create_field *field;
+    while ((field=it++))
+    {
+      if (field->interval && field->charset->mbminlen > 1)
+        unhex_type2(field->interval);
+    }
+  }
   DBUG_RETURN(0);
 
 err: