Bug#52121 partition by key on utf32 enum field cause debug assertion: (length % 4) == 0

      
Problem: ENUM columns are sorted and distributed according to their
numeric value, but Field::hash() incorrectly passed string character set
(utf32) in combination with numeric value to the hash function,
which made assertion fail.

Fix: pass "binary" character set in combination with numeric value
to the hash function.

  mysql-test/suite/parts/r/part_ctype_utf32.result
  Adding tests

  mysql-test/suite/parts/t/part_ctype_utf32.test
  Adding test

  sql/field.cc
  Pass correct character set pointer to the hash function.

mysql-test/suite/parts/r/part_ctype_utf32.result

+#
+# Bug#52121 partition by key on utf32 enum field cause debug assertion: (length % 4) == 0
+#
+DROP TABLE IF EXISTS t1;
+Warnings:
+Note	1051	Unknown table 't1'
+CREATE TABLE t1 (
+a enum('a') CHARACTER SET utf32 COLLATE utf32_spanish2_ci
+) ENGINE=MYISAM PARTITION BY KEY(a) PARTITIONS 2;
+INSERT INTO t1 VALUES ('a');
+SELECT * FROM t1;
+a
+a
+DROP TABLE t1;

mysql-test/suite/parts/t/part_ctype_utf32.test

+################################################################################
+# t/partition_ctype_utf32.test                                                 #
+#                                                                              #
+# Purpose:                                                                     #
+#  Tests for partitions + UTF32                                                #
+#                                                                              #
+#------------------------------------------------------------------------------#
+# Original Author: Alexander Barkov                                            #
+# Original Date: 2010-08-05                                                    #
+# Change Author:                                                               #
+# Change Date:                                                                 #
+# Change:                                                                      #
+################################################################################
+
+--source include/have_partition.inc
+--source include/have_utf32.inc
+
+--echo #
+--echo # Bug#52121 partition by key on utf32 enum field cause debug assertion: (length % 4) == 0
+--echo #
+
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (
+ a enum('a') CHARACTER SET utf32 COLLATE utf32_spanish2_ci
+) ENGINE=MYISAM PARTITION BY KEY(a) PARTITIONS 2;
+INSERT INTO t1 VALUES ('a');
+SELECT * FROM t1;
+DROP TABLE t1;

sql/field.cc

@@ -1329,7 +1329,7 @@ void Field::hash(ulong *nr, ulong *nr2)
   else
   {
     uint len= pack_length();
-    CHARSET_INFO *cs= charset();
+    CHARSET_INFO *cs= sort_charset();
     cs->coll->hash_sort(cs, ptr, len, nr, nr2);
   }
 }