merge of bug 47902 and (null-merge) of bug 57924.

bug#57924 does not occur in 5.5, so I reverted the 5.1 specific
code and used the errors from 5.5 instead in the tests

client/mysqltest.cc

@@ -7555,7 +7555,11 @@ void run_query_stmt(MYSQL *mysql, struct st_command *command,
 
       mysql_free_result(res);     /* Free normal result set with meta data */
 
-      /* Clear prepare warnings */
+      /*
+        Clear prepare warnings if there are execute warnings,
+        since they are probably duplicated.
+      */
+      if (ds_execute_warnings.length || mysql->warning_count)
         dynstr_set(&ds_prepare_warnings, NULL);
     }
     else

mysql-test/r/partition_error.result

 drop table if exists t1, t2;
 #
+# Bug#57924: crash when creating partitioned table with
+#            multiple columns in the partition key
+#
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a,b))
+PARTITION BY KEY(a, b, a);
+ERROR HY000: Duplicate partition field name 'a'
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a,b))
+PARTITION BY KEY(A, b);
+DROP TABLE t1;
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a,b))
+PARTITION BY KEY(a, b, A);
+ERROR HY000: Duplicate partition field name 'a'
+#
 # Bug#54483: valgrind errors when making warnings for multiline inserts
 #            into partition
 #

mysql-test/t/partition_error.test

@@ -10,6 +10,21 @@ drop table if exists t1, t2;
 
 let $MYSQLD_DATADIR= `SELECT @@datadir`;
 
+--echo #
+--echo # Bug#57924: crash when creating partitioned table with
+--echo #            multiple columns in the partition key
+--echo #
+--error ER_SAME_NAME_PARTITION_FIELD
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a,b))
+PARTITION BY KEY(a, b, a);
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a,b))
+PARTITION BY KEY(A, b);
+DROP TABLE t1;
+--error ER_SAME_NAME_PARTITION_FIELD
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a,b))
+PARTITION BY KEY(a, b, A);
+
+
 --echo #
 --echo # Bug#54483: valgrind errors when making warnings for multiline inserts
 --echo #            into partition
@@ -670,7 +685,6 @@ PARTITION BY HASH (TIME_TO_SEC(a));
 CREATE TABLE t1 (a INT)
 PARTITION BY HASH (TIME_TO_SEC(a));
 
-
 --echo #
 --echo # Bug#50036: Inconsistent errors when using TIMESTAMP
 --echo #            columns/expressions