BUG#19304: Merge handler allowed in partitioned tables

mysql-test/r/partition.result:
  New test case
mysql-test/t/partition.test:
  New test case
sql/partition_info.cc:
  Check for not merge handler in partitioned table
sql/share/errmsg.txt:
  New error message

mysql-test/r/partition.result

@@ -886,4 +886,8 @@ s1
 2
 3
 drop table t1;
+create table t1 (a int)
+partition by key (a)
+(partition p0 engine = MERGE);
+ERROR HY000: MyISAM Merge handler cannot be used in partitioned tables
 End of 5.1 tests

mysql-test/t/partition.test

@@ -1009,4 +1009,12 @@ select auto_increment from information_schema.tables where table_name='t1';
 select * from t1;
 drop table t1;
 
+#
+# BUG 19304 Partitions: MERGE handler not allowed in partitioned tables
+#
+--error ER_PARTITION_MERGE_ERROR
+create table t1 (a int)
+partition by key (a)
+(partition p0 engine = MERGE);
+
 --echo End of 5.1 tests

sql/partition_info.cc

@@ -431,18 +431,22 @@ char *partition_info::has_unique_names()
 bool partition_info::check_engine_mix(handlerton **engine_array, uint no_parts)
 {
   uint i= 0;
-  bool result= FALSE;
   DBUG_ENTER("partition_info::check_engine_mix");
 
   do
   {
     if (engine_array[i] != engine_array[0])
     {
-      result= TRUE;
-      break;
+      my_error(ER_MIX_HANDLER_ERROR, MYF(0));
+      DBUG_RETURN(TRUE);
     }
   } while (++i < no_parts);
-  DBUG_RETURN(result);
+  if (!strcmp(engine_array[0]->name,"MRG_MYISAM"))
+  {
+    my_error(ER_PARTITION_MERGE_ERROR, MYF(0));
+    DBUG_RETURN(TRUE);
+  }
+  DBUG_RETURN(FALSE);
 }
 
 
@@ -756,10 +760,7 @@ bool partition_info::check_partition_info(handlerton **eng_type,
     } while (++i < no_parts);
   }
   if (unlikely(partition_info::check_engine_mix(engine_array, part_count)))
-  {
-    my_error(ER_MIX_HANDLER_ERROR, MYF(0));
     goto end;
-  }
 
   if (eng_type)
     *eng_type= (handlerton*)engine_array[0];

sql/share/errmsg.txt

@@ -5840,3 +5840,6 @@ ER_NULL_IN_VALUES_LESS_THAN
 ER_WRONG_PARTITION_NAME
         eng "Incorrect partition name"
         swe "Felaktigt partitionsnamn"
+ER_PARTITION_MERGE_ERROR
+        eng "MyISAM Merge handler cannot be used in partitioned tables"
+        swe "MyISAM Merge kan inte anndas i en partitionerad tabell"