BUG#18198: Too much expressiveness in partition functions allowed

First step


sql/item.h:
  Add function to check for partition function whether allowed or not.
  In this first step allow only a field on its own.
  Further steps will add a lot more possibilities.
sql/partition_info.cc:
  Add a check whether the partition function is allowed by walking the
  partition function expression.
sql/share/errmsg.txt:
  Add a new error code for partition function not allowed

sql/item.h

@@ -744,6 +744,11 @@ class Item {
   virtual bool find_item_in_field_list_processor(byte *arg) { return 0; }
   virtual bool change_context_processor(byte *context) { return 0; }
   virtual bool reset_query_id_processor(byte *query_id) { return 0; }
+  virtual bool check_partition_func_processor(byte *bool_arg)
+  {
+    *(bool *)bool_arg= FALSE;
+    return 0;
+  }
 
   virtual Item *equal_fields_propagator(byte * arg) { return this; }
   virtual Item *set_no_const_sub(byte *arg) { return this; }
@@ -1202,6 +1207,7 @@ class Item_field :public Item_ident
       result_field->query_id= field->query_id;
     return 0;
   }
+  bool check_partition_func_processor(byte *bool_arg) { return 0; }
   void cleanup();
   Item_equal *find_item_equal(COND_EQUAL *cond_equal);
   Item *equal_fields_propagator(byte *arg);

sql/partition_info.cc

@@ -655,8 +655,15 @@ bool partition_info::check_partition_info(handlerton **eng_type,
   uint i, tot_partitions;
   bool result= TRUE;
   char *same_name;
+  bool part_expression_ok= TRUE;
   DBUG_ENTER("partition_info::check_partition_info");
 
+  if (part_expr->walk(Item::check_partition_func_processor,
+                      (byte*)&part_expression_ok))
+  {
+    my_error(ER_PARTITION_FUNC_NOT_ALLOWED, MYF(0));
+    goto end;
+  }
   if (unlikely(!is_sub_partitioned() && 
                !(use_default_subpartitions && use_default_no_subpartitions)))
   {

sql/share/errmsg.txt

@@ -5826,3 +5826,6 @@ ER_NDB_CANT_SWITCH_BINLOG_FORMAT
 	eng "The NDB cluster engine does not support changing the binlog format on the fly yet"
 ER_PARTITION_NO_TEMPORARY
 	eng "Cannot create temporary table with partitions"
+ER_PARTITION_FUNCTION_NOT_ALLOWED
+        eng "This partition function is not allowed"
+        swe "Denna partitioneringsfunktion r inte tillten"