Bug#31384 DATE_ADD() and DATE_SUB() return binary data

Problem: DATE_ADD() is a hybrid function and can return
DATE, DATETIME or VARCHAR data type depending on arguments.

In case of VARCHAR data type, DATE_ADD() reported "binary" character set,
which was wrong.

Fix: make DATE_ADD() return @character_set_connection in VARCHAR context.
 @ mysql-test/include/ctype_numconv.inc
   Adding tests
 @ mysql-test/r/ctype_binary.result
   Adding tests
 @ mysql-test/r/ctype_cp1251.result
   Adding tests
 @ mysql-test/r/ctype_latin1.result
   Adding tests
 @ mysql-test/r/ctype_ucs.result
   Adding tests
 @ mysql-test/r/ctype_utf8.result
   Adding tests
 @ sql/item_strfunc.cc
  - Moving code from Item_str_ascii_func::val_str() to
  Item_str_func::val_str_from_val_str_ascii(), as
  this code needs to be shared by Item_date_add_interval.
  - Adding str2 parameter to be used as a buffer, instead of
   using private ascii_buf member.
 @ sql/item_strfunc.h
  - Moving code from Item_str_ascii_func::val_str() to
  Item_str_func::val_str_from_val_str_ascii()
  - Removing "String *val_str_convert_from_ascii(String *str, String *ascii_buf)"
    prototype as it was neither used nor declared.
 @ sql/item_timefunc.h
  - Overwriting parent's charset_for_protocol() method,
    becase we need to behave differenlty in VARCHAR and DATE/DATETYPE context.
  - Adding ascii_buf for conversion.
  - Adding val_str_ascii() prototype.
  - Adding val_str() which uses newly added
    Item_str_func::val_str_from_val_str_ascii(),
    passing ascii_buf as a conversion buffer.

1 files changed, 7 insertions, 7 deletions

diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index 25eb08ffa75..0248c133f60 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -70,7 +70,7 @@ String my_empty_string("",default_charset_info);
   Normally conversion does not happen, and val_str_ascii() is immediately
   returned instead.
 */
-String *Item_str_ascii_func::val_str(String *str)
+String *Item_str_func::val_str_from_val_str_ascii(String *str, String *str2)
 {
   DBUG_ASSERT(fixed == 1);
 
@@ -82,19 +82,19 @@ String *Item_str_ascii_func::val_str(String *str)
     return res;
   }
   
-  DBUG_ASSERT(str != &ascii_buf);
+  DBUG_ASSERT(str != str2);
   
   uint errors;
-  String *res= val_str_ascii(&ascii_buf);
+  String *res= val_str_ascii(str);
   if (!res)
     return 0;
   
-  if ((null_value= str->copy(res->ptr(), res->length(),
-                             &my_charset_latin1, collation.collation,
-                             &errors)))
+  if ((null_value= str2->copy(res->ptr(), res->length(),
+                              &my_charset_latin1, collation.collation,
+                              &errors)))
     return 0;
   
-  return str;
+  return str2;
 }