aliases should be compared with my_strcasecmp (BUG#3251)

some db comparison code cleupup
removed compiler warnings


mysql-test/r/lowercase_table.result:
  test for BUG#3251
mysql-test/t/lowercase_table.test:
  test for BUG#3251
sql/item.cc:
  simple strcmp can be used for db name comparison
sql/set_var.h:
  changed initialisation order to satisfy compiler
sql/sql_cache.cc:
  simple strcmp can be used for db name comparison
sql/sql_db.cc:
  better use special cherset for files
sql/sql_parse.cc:
  simple strcmp can be used for db name comparison
  aliases should be compared with my_strcasecmp
sql/sql_select.cc:
  aliases should be compared with my_strcasecmp

mysql-test/r/lowercase_table.result

-drop table if exists t1,t2,t3,t4,T1;
+drop table if exists t1,t2,t3,t4;
 create table T1 (id int primary key, Word varchar(40) not null, Index(Word));
 create table t4 (id int primary key, Word varchar(40) not null);
 INSERT INTO T1 VALUES (1, 'a'), (2, 'b'), (3, 'c');
@@ -49,3 +49,12 @@ delete P1.*,p2.* from t1 as P1, t2 as P2 where P1.a=p2.a;
 update t1 as p1, t2 as p2 SET p1.a=1,P2.a=1 where p1.a=P2.a;
 update t1 as P1, t2 as P2 SET P1.a=1,p2.a=1 where P1.a=p2.a;
 drop table t1,t2;
+create table t1 (a int);
+create table t2 (a int);
+select * from t1 c, t2 C;
+ERROR 42000: Not unique table/alias: 'C'
+select C.a, c.a from t1 c, t2 C;
+ERROR 42000: Not unique table/alias: 'C'
+drop table t1, t2;
+show tables;
+Tables_in_test

mysql-test/t/lowercase_table.test

@@ -3,7 +3,7 @@
 #
 
 --disable_warnings
-drop table if exists t1,t2,t3,t4,T1;
+drop table if exists t1,t2,t3,t4;
 --enable_warnings
 
 create table T1 (id int primary key, Word varchar(40) not null, Index(Word));
@@ -41,3 +41,16 @@ delete P1.*,p2.* from t1 as P1, t2 as P2 where P1.a=p2.a;
 update t1 as p1, t2 as p2 SET p1.a=1,P2.a=1 where p1.a=P2.a;
 update t1 as P1, t2 as P2 SET P1.a=1,p2.a=1 where P1.a=p2.a;
 drop table t1,t2;
+
+#
+# aliases case insensitive
+#
+create table t1 (a int);
+create table t2 (a int);
+-- error 1066
+select * from t1 c, t2 C;
+-- error 1066
+select C.a, c.a from t1 c, t2 C;
+drop table t1, t2;
+
+show tables;

sql/item.cc

@@ -456,9 +456,8 @@ bool Item_field::eq(const Item *item, bool binary_cmp) const
 	   (!my_strcasecmp(table_alias_charset, item_field->table_name,
 			   table_name) &&
 	    (!item_field->db_name ||
-	     (item_field->db_name && !my_strcasecmp(table_alias_charset,
-						    item_field->db_name,
-						    db_name))))));
+	     (item_field->db_name && !strcmp(item_field->db_name,
+					     db_name))))));
 }
 
 

sql/set_var.h

@@ -141,7 +141,7 @@ class sys_var_str :public sys_var
 	      sys_update_func update_func_arg,
 	      sys_set_default_func set_default_func_arg,
               char *value_arg)
-    :sys_var(name_arg), check_func(check_func_arg), value(value_arg),
+    :sys_var(name_arg), value(value_arg), check_func(check_func_arg),
     update_func(update_func_arg),set_default_func(set_default_func_arg)
   {}
   bool check(THD *thd, set_var *var);

sql/sql_cache.cc

@@ -1259,12 +1259,7 @@ void Query_cache::invalidate(char *db)
 	do
 	{
 	  next= curr->next;
-	  /*
-	    table_alias_charset used here because it depends of
-	    lower_case_table_names variable
-	  */
-	  if (my_strcasecmp(table_alias_charset, db, 
-			    (char*)(curr->table()->db())) == 0)
+	  if (strcmp(db, (char*)(curr->table()->db())) == 0)
 	    invalidate_table(curr);
 	  /*
 	    invalidate_table can freed block on which point 'next' (if

sql/sql_db.cc

@@ -504,7 +504,8 @@ static long mysql_rm_known_files(THD *thd, MY_DIR *dirp, const char *db,
 	found_other_files++;
       continue;
     }
-    if (db && !my_strcasecmp(&my_charset_latin1,
+    // just for safety we use files_charset_info
+    if (db && !my_strcasecmp(files_charset_info,
                              extension, reg_ext))
     {
       /* Drop the table nicely */

sql/sql_parse.cc

@@ -2712,7 +2712,7 @@ mysql_execute_command(THD *thd)
       for (walk= (TABLE_LIST*) tables; walk; walk= walk->next)
       {
 	if (!my_strcasecmp(table_alias_charset, auxi->alias, walk->alias) &&
-	    !my_strcasecmp(table_alias_charset, walk->db, auxi->db))
+	    !strcmp(walk->db, auxi->db))
 	  break;
       }
       if (!walk)
@@ -4495,7 +4495,8 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
 	 tables ;
 	 tables=tables->next)
     {
-      if (!strcmp(alias_str,tables->alias) && !strcmp(ptr->db, tables->db))
+      if (!my_strcasecmp(table_alias_charset, alias_str, tables->alias) &&
+	  !strcmp(ptr->db, tables->db))
       {
 	net_printf(thd,ER_NONUNIQ_TABLE,alias_str); /* purecov: tested */
 	DBUG_RETURN(0);				/* purecov: tested */

sql/sql_select.cc

@@ -9376,7 +9376,7 @@ void st_select_lex::print(THD *thd, String *str)
 	str->append(table->db);
 	str->append('.');
 	str->append(table->real_name);
-	if (strcmp(table->real_name, table->alias))
+	if (my_strcasecmp(table_alias_charset, table->real_name, table->alias))
 	{
 	  str->append(' ');
 	  str->append(table->alias);