MDEV-8912 Wrong metadata or type for @c:=string_or_blob_field

1 files changed, 51 insertions, 20 deletions

diff --git a/sql/item_func.h b/sql/item_func.h
index 917ae0ed02e..921063f8809 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -175,6 +175,12 @@ public:
   friend class udf_handler;
   Field *tmp_table_field() { return result_field; }
   Field *tmp_table_field(TABLE *t_arg);
+  Field *create_field_for_create_select(THD *thd, TABLE *table)
+  {
+    return result_type() != STRING_RESULT ?
+           tmp_table_field(table) :
+           tmp_table_field_from_field_type(table, false, false);
+  }
   Item *get_tmp_table_item(THD *thd);
 
   my_decimal *val_decimal(my_decimal *);
@@ -1618,10 +1624,39 @@ public:
 
 class user_var_entry;
 
-class Item_func_set_user_var :public Item_func
+
+/**
+  A class to set and get user variables
+*/
+class Item_func_user_var :public Item_func,
+                          public Type_handler_hybrid_field_type
+{
+protected:
+  user_var_entry *m_var_entry;
+public:
+  LEX_STRING name; // keep it public
+  Item_func_user_var(THD *thd, LEX_STRING a)
+    :Item_func(thd), m_var_entry(NULL), name(a) { }
+  Item_func_user_var(THD *thd, LEX_STRING a, Item *b)
+    :Item_func(thd, b), m_var_entry(NULL), name(a) { }
+  Item_func_user_var(THD *thd, Item_func_user_var *item)
+    :Item_func(thd, item),
+    m_var_entry(item->m_var_entry), name(item->name)
+  {
+    set_handler_by_result_type(item->result_type());
+  }
+  enum Item_result cmp_type() const
+  { return Type_handler_hybrid_field_type::cmp_type(); }
+  enum Item_result result_type() const
+  { return Type_handler_hybrid_field_type::result_type(); }
+  enum_field_types field_type() const
+  { return Type_handler_hybrid_field_type::field_type(); }
+  bool check_vcol_func_processor(uchar *int_arg) { return true; }
+};
+
+
+class Item_func_set_user_var :public Item_func_user_var
 {
-  enum Item_result cached_result_type;
-  user_var_entry *entry;
   /*
     The entry_thread_id variable is used:
     1) to skip unnecessary updates of the entry field (see above);
@@ -1646,17 +1681,15 @@ class Item_func_set_user_var :public Item_func
   } save_result;
 
 public:
-  LEX_STRING name; // keep it public
   Item_func_set_user_var(THD *thd, LEX_STRING a, Item *b):
-    Item_func(thd, b), cached_result_type(INT_RESULT),
-    entry(NULL), entry_thread_id(0), name(a)
+    Item_func_user_var(thd, a, b),
+    entry_thread_id(0)
   {}
   Item_func_set_user_var(THD *thd, Item_func_set_user_var *item)
-    :Item_func(thd, item), cached_result_type(item->cached_result_type),
-    entry(item->entry), entry_thread_id(item->entry_thread_id),
+    :Item_func_user_var(thd, item),
+    entry_thread_id(item->entry_thread_id),
     value(item->value), decimal_buff(item->decimal_buff),
-    null_item(item->null_item), save_result(item->save_result),
-    name(item->name)
+    null_item(item->null_item), save_result(item->save_result)
   {}
 
   enum Functype functype() const { return SUSERVAR_FUNC; }
@@ -1677,9 +1710,14 @@ public:
   bool check(bool use_result_field);
   void save_item_result(Item *item);
   bool update();
-  enum Item_result result_type () const { return cached_result_type; }
   bool fix_fields(THD *thd, Item **ref);
   void fix_length_and_dec();
+  Field *create_field_for_create_select(THD *thd, TABLE *table)
+  {
+    return result_type() != STRING_RESULT ?
+           tmp_table_field(table) :
+           tmp_table_field_from_field_type(table, false, true);
+  }
   table_map used_tables() const
   {
     return Item_func::used_tables() | RAND_TABLE_BIT;
@@ -1702,20 +1740,15 @@ public:
   bool register_field_in_bitmap(uchar *arg);
   bool set_entry(THD *thd, bool create_if_not_exists);
   void cleanup();
-  bool check_vcol_func_processor(uchar *int_arg) {return TRUE;}
 };
 
 
-class Item_func_get_user_var :public Item_func,
+class Item_func_get_user_var :public Item_func_user_var,
                               private Settable_routine_parameter
 {
-  user_var_entry *var_entry;
-  Item_result m_cached_result_type;
-
 public:
-  LEX_STRING name; // keep it public
   Item_func_get_user_var(THD *thd, LEX_STRING a):
-    Item_func(thd), m_cached_result_type(STRING_RESULT), name(a) {}
+    Item_func_user_var(thd, a) {}
   enum Functype functype() const { return GUSERVAR_FUNC; }
   LEX_STRING get_name() { return name; }
   double val_real();
@@ -1724,7 +1757,6 @@ public:
   String *val_str(String* str);
   void fix_length_and_dec();
   virtual void print(String *str, enum_query_type query_type);
-  enum Item_result result_type() const;
   /*
     We must always return variables as strings to guard against selects of type
     select @t1:=1,@t1,@t:="hello",@t from foo where (@t1:= t2.b)
@@ -1742,7 +1774,6 @@ public:
   {
     return this;
   }
-  bool check_vcol_func_processor(uchar *int_arg) { return TRUE;}
 };