Fix for bug #20695: Charset introducer overrides charset definition for column.

  - if there are two character set definitions in the column declaration,
    we replace the first one with the second one as we store both in the LEX->charset
    slot. Add a separate slot to the LEX structure to store underscore charset.
  - convert default values to the column charset of STRING, VARSTRING fields 
    if necessary as well.


mysql-test/r/ctype_recoding.result:
  Fix for bug #20695: Charset introducer overrides charset definition for column.
    - test result.
mysql-test/t/ctype_recoding.test:
  Fix for bug #20695: Charset introducer overrides charset definition for column.
    - test case.
sql/sql_lex.cc:
  Fix for bug #20695: Charset introducer overrides charset definition for column.
    - LEX->underscore_charset introduced to store UNDERSCORE_CHARSET
sql/sql_lex.h:
  Fix for bug #20695: Charset introducer overrides charset definition for column.
    - LEX->underscore_charset introduced to store UNDERSCORE_CHARSET
sql/sql_table.cc:
  Fix for bug #20695: Charset introducer overrides charset definition for column.
    - convert default values to the column charset of VARSTRING, STRING, ENUM, 
      SET fields if necessary.
sql/sql_yacc.yy:
  Fix for bug #20695: Charset introducer overrides charset definition for column.
    - LEX->underscore_charset introduced to store UNDERSCORE_CHARSET

6 files changed, 63 insertions, 34 deletions

diff --git a/mysql-test/r/ctype_recoding.result b/mysql-test/r/ctype_recoding.result
index 0b5c6f8974c..2daa2d5ba0b 100644
--- a/mysql-test/r/ctype_recoding.result
+++ b/mysql-test/r/ctype_recoding.result
@@ -247,3 +247,14 @@ lpad(c1,3,'ö')	lpad('ö',3,c1)
 select rpad(c1,3,'ö'), rpad('ö',3,c1) from t1;
 rpad(c1,3,'ö')	rpad('ö',3,c1)
 ßöö	ößß
+drop table t1;
+set names koi8r;
+create table t1(a char character set cp1251 default _koi8r 0xFF);
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` char(1) character set cp1251 default 'ÿ'
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t1;
+create table t1(a char character set latin1 default _cp1251 0xFF);
+ERROR 42000: Invalid default value for 'a'
diff --git a/mysql-test/t/ctype_recoding.test b/mysql-test/t/ctype_recoding.test
index 5648cea7fd3..ddaaa7b9e4f 100644
--- a/mysql-test/t/ctype_recoding.test
+++ b/mysql-test/t/ctype_recoding.test
@@ -186,5 +186,17 @@ select rpad(c1,3,'ö'), rpad('ö',3,c1) from t1;
 # TODO
 #select case c1 when 'ß' then 'ß' when 'ö' then 'ö' else 'c' end from t1;
 #select export_set(5,c1,'ö'), export_set(5,'ö',c1) from t1;
+drop table t1;
+
+#
+# Bug 20695: problem with field default value's character set
+#
+
+set names koi8r;
+create table t1(a char character set cp1251 default _koi8r 0xFF);
+show create table t1;
+drop table t1;
+--error 1067
+create table t1(a char character set latin1 default _cp1251 0xFF);
 
 # End of 4.1 tests
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index fb9a765f12c..dfe406c351e 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -643,8 +643,9 @@ int yylex(void *arg, void *yythd)
       */
 
       if ((yylval->lex_str.str[0]=='_') && 
-          (lex->charset=get_charset_by_csname(yylval->lex_str.str+1,
-					      MY_CS_PRIMARY,MYF(0))))
+          (lex->underscore_charset=
+             get_charset_by_csname(yylval->lex_str.str + 1,
+                                   MY_CS_PRIMARY,MYF(0))))
         return(UNDERSCORE_CHARSET);
       return(result_state);			// IDENT or IDENT_QUOTED
 
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 35f02db6cf9..12f89202e2d 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -613,7 +613,7 @@ typedef struct st_lex
   LEX_USER *grant_user;
   gptr yacc_yyss,yacc_yyvs;
   THD *thd;
-  CHARSET_INFO *charset;
+  CHARSET_INFO *charset, *underscore_charset;
 
   List<key_part_spec> col_list;
   List<key_part_spec> ref_list;
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 631d2d89bbb..a5cb0d45664 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -516,6 +516,40 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
       DBUG_RETURN(-1);
     }
 
+    /*
+      Convert the default value character
+      set into the column character set if necessary.
+    */
+    if (sql_field->def && 
+        savecs != sql_field->def->collation.collation &&
+        (sql_field->sql_type == FIELD_TYPE_VAR_STRING ||
+         sql_field->sql_type == FIELD_TYPE_STRING ||
+         sql_field->sql_type == FIELD_TYPE_SET ||
+         sql_field->sql_type == FIELD_TYPE_ENUM))
+    {
+      Item_arena backup_arena;
+      bool need_to_change_arena=
+        !thd->current_arena->is_conventional_execution();
+      if (need_to_change_arena)
+      {
+        /* Assert that we don't do that at every PS execute */
+        DBUG_ASSERT(thd->current_arena->is_first_stmt_execute());
+        thd->set_n_backup_item_arena(thd->current_arena, &backup_arena);
+      }
+
+      sql_field->def= sql_field->def->safe_charset_converter(savecs);
+
+      if (need_to_change_arena)
+        thd->restore_backup_item_arena(thd->current_arena, &backup_arena);
+
+      if (sql_field->def == NULL)
+      {
+        /* Could not convert */
+        my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
+        DBUG_RETURN(-1);
+      }
+    }
+
     if (sql_field->sql_type == FIELD_TYPE_SET ||
         sql_field->sql_type == FIELD_TYPE_ENUM)
     {
@@ -580,35 +614,6 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
         sql_field->interval_list.empty(); // Don't need interval_list anymore
       }
 
-      /*
-        Convert the default value from client character
-        set into the column character set if necessary.
-      */
-      if (sql_field->def && cs != sql_field->def->collation.collation)
-      {
-        Item_arena backup_arena;
-        bool need_to_change_arena=
-          !thd->current_arena->is_conventional_execution();
-        if (need_to_change_arena)
-        {
-          /* Asser that we don't do that at every PS execute */
-          DBUG_ASSERT(thd->current_arena->is_first_stmt_execute());
-          thd->set_n_backup_item_arena(thd->current_arena, &backup_arena);
-        }
-
-        sql_field->def= sql_field->def->safe_charset_converter(cs);
-
-        if (need_to_change_arena)
-          thd->restore_backup_item_arena(thd->current_arena, &backup_arena);
-
-        if (sql_field->def == NULL)
-        {
-          /* Could not convert */
-          my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
-          DBUG_RETURN(-1);
-        }
-      }
-
       if (sql_field->sql_type == FIELD_TYPE_SET)
       {
         if (sql_field->def != NULL)
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 162b4183c84..efd83549312 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -4896,7 +4896,7 @@ text_literal:
 	| NCHAR_STRING
 	{ $$=  new Item_string($1.str,$1.length,national_charset_info); }
 	| UNDERSCORE_CHARSET TEXT_STRING
-	  { $$ = new Item_string($2.str,$2.length,Lex->charset); }
+	  { $$ = new Item_string($2.str,$2.length,Lex->underscore_charset); }
 	| text_literal TEXT_STRING_literal
 	  { ((Item_string*) $1)->append($2.str,$2.length); }
 	;
@@ -4963,7 +4963,7 @@ literal:
 	      (String*) 0;
 	    $$= new Item_string(str ? str->ptr() : "",
 				str ? str->length() : 0,
-				Lex->charset);
+				Lex->underscore_charset);
 	  }
 	| DATE_SYM text_literal { $$ = $2; }
 	| TIME_SYM text_literal { $$ = $2; }