Bug #7498 User variable SET saves SIGNED BIGINT as UNSIGNED BIGINT

- Add unsigned flag to user_var_entry, used when 'type' is INT_RESULT
- Propagate unsigned flag from the query executed by Item_single_row_subselect


mysql-test/r/user_var.result:
  Update test results
mysql-test/t/user_var.test:
  Add test case
sql/item_func.cc:
  Add unsigned_flag to user_var_entry. Used when 'type' is INT_RESULT
  Pass unsigned_flag to 'update_hash' if type is INT_RESULT
sql/item_func.h:
  Removed unused variable save_buff
  Add parameter unsigned_arg to 'update_hash'
sql/item_subselect.cc:
  Propagate unsigned_flag to Item_singlerow_subselect from the items in the select to the cached items.
sql/sql_class.h:
  Add unsigned_flag to user_var_entry. Used when 'type' is INT_RESULT

4 files changed, 21 insertions, 11 deletions

diff --git a/sql/item_func.cc b/sql/item_func.cc
index 6ec74560b91..7450451b0d0 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -3408,6 +3408,7 @@ static user_var_entry *get_variable(HASH *hash, LEX_STRING &name,
     entry->length=0;
     entry->update_query_id=0;
     entry->collation.set(NULL, DERIVATION_IMPLICIT);
+    entry->unsigned_flag= 0;
     /*
       If we are here, we were called from a SET or a query which sets a
       variable. Imagine it is this:
@@ -3494,6 +3495,7 @@ Item_func_set_user_var::fix_length_and_dec()
     type     - type of new value
     cs       - charset info for new value
     dv       - derivation for new value
+    unsigned_arg - indiates if a value of type INT_RESULT is unsigned
 
   RETURN VALUE
     False - success, True - failure
@@ -3501,7 +3503,8 @@ Item_func_set_user_var::fix_length_and_dec()
 
 static bool
 update_hash(user_var_entry *entry, bool set_null, void *ptr, uint length,
-            Item_result type, CHARSET_INFO *cs, Derivation dv)
+            Item_result type, CHARSET_INFO *cs, Derivation dv,
+            bool unsigned_arg)
 {
   if (set_null)
   {
@@ -3549,6 +3552,7 @@ update_hash(user_var_entry *entry, bool set_null, void *ptr, uint length,
       ((my_decimal*)entry->value)->fix_buffer_pointer();
     entry->length= length;
     entry->collation.set(cs, dv);
+    entry->unsigned_flag= unsigned_arg;
   }
   entry->type=type;
   return 0;
@@ -3557,7 +3561,8 @@ update_hash(user_var_entry *entry, bool set_null, void *ptr, uint length,
 
 bool
 Item_func_set_user_var::update_hash(void *ptr, uint length, Item_result type,
-                                    CHARSET_INFO *cs, Derivation dv)
+                                    CHARSET_INFO *cs, Derivation dv,
+                                    bool unsigned_arg)
 {
   /*
     If we set a variable explicitely to NULL then keep the old
@@ -3566,7 +3571,7 @@ Item_func_set_user_var::update_hash(void *ptr, uint length, Item_result type,
   if ((null_value= args[0]->null_value) && null_item)
     type= entry->type;                          // Don't change type of item
   if (::update_hash(entry, (null_value= args[0]->null_value),
-                    ptr, length, type, cs, dv))
+                    ptr, length, type, cs, dv, unsigned_arg))
   {
     current_thd->fatal_error();     // Probably end of memory
     null_value= 1;
@@ -3648,7 +3653,10 @@ String *user_var_entry::val_str(my_bool *null_value, String *str,
     str->set(*(double*) value, decimals, &my_charset_bin);
     break;
   case INT_RESULT:
-    str->set(*(longlong*) value, &my_charset_bin);
+    if (!unsigned_flag)
+      str->set(*(longlong*) value, &my_charset_bin);
+    else
+      str->set(*(ulonglong*) value, &my_charset_bin);
     break;
   case DECIMAL_RESULT:
     my_decimal2string(E_DEC_FATAL_ERROR, (my_decimal *)value, 0, 0, 0, str);
@@ -3719,6 +3727,7 @@ Item_func_set_user_var::check()
   case INT_RESULT:
   {
     save_result.vint= args[0]->val_int();
+    unsigned_flag= args[0]->unsigned_flag;
     break;
   }
   case STRING_RESULT:
@@ -3774,7 +3783,8 @@ Item_func_set_user_var::update()
   case INT_RESULT:
   {
     res= update_hash((void*) &save_result.vint, sizeof(save_result.vint),
-		     INT_RESULT, &my_charset_bin, DERIVATION_IMPLICIT);
+		     INT_RESULT, &my_charset_bin, DERIVATION_IMPLICIT,
+                     unsigned_flag);
     break;
   }
   case STRING_RESULT:
@@ -4141,7 +4151,7 @@ bool Item_user_var_as_out_param::fix_fields(THD *thd, Item **ref)
 void Item_user_var_as_out_param::set_null_value(CHARSET_INFO* cs)
 {
   if (::update_hash(entry, TRUE, 0, 0, STRING_RESULT, cs,
-                    DERIVATION_IMPLICIT))
+                    DERIVATION_IMPLICIT, 0 /* unsigned_arg */))
     current_thd->fatal_error();			// Probably end of memory
 }
 
@@ -4150,7 +4160,7 @@ void Item_user_var_as_out_param::set_value(const char *str, uint length,
                                            CHARSET_INFO* cs)
 {
   if (::update_hash(entry, FALSE, (void*)str, length, STRING_RESULT, cs,
-                    DERIVATION_IMPLICIT))
+                    DERIVATION_IMPLICIT, 0 /* unsigned_arg */))
     current_thd->fatal_error();			// Probably end of memory
 }
 
diff --git a/sql/item_func.h b/sql/item_func.h
index a91d93be8c6..8f90626ad26 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -1154,8 +1154,6 @@ class Item_func_set_user_var :public Item_func
     String *vstr;
     my_decimal *vdec;
   } save_result;
-  String save_buff;
-  
 
 public:
   LEX_STRING name; // keep it public
@@ -1166,8 +1164,8 @@ public:
   longlong val_int();
   String *val_str(String *str);
   my_decimal *val_decimal(my_decimal *);
-  bool update_hash(void *ptr, uint length, enum Item_result type, 
-  		   CHARSET_INFO *cs, Derivation dv);
+  bool update_hash(void *ptr, uint length, enum Item_result type,
+  		   CHARSET_INFO *cs, Derivation dv, bool unsigned_arg= 0);
   bool check();
   bool update();
   enum Item_result result_type () const { return cached_result_type; }
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index d93f6501ebb..4e6b168c9e9 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -1497,6 +1497,7 @@ static Item_result set_row(List<Item> &item_list, Item *item,
     item->max_length= sel_item->max_length;
     res_type= sel_item->result_type();
     item->decimals= sel_item->decimals;
+    item->unsigned_flag= sel_item->unsigned_flag;
     *maybe_null= sel_item->maybe_null;
     if (!(row[i]= Item_cache::get_cache(res_type)))
       return STRING_RESULT; // we should return something
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 0ddba0e6f05..be13084b1ea 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -1954,6 +1954,7 @@ class user_var_entry
   ulong length;
   query_id_t update_query_id, used_query_id;
   Item_result type;
+  bool unsigned_flag;
 
   double val_real(my_bool *null_value);
   longlong val_int(my_bool *null_value);