Bug#26703: DROP DATABASE fails if database contains a #mysql50# \

	table with backticks

(Thanks to Lu Jingdong, though I did not take his patch directly, as
it contained a significant flaw.)

It wasn't a backtick/parsing problem.  We merely didn't anticipate
and allocate enough space to handle the optional "#mysql50#" table-
name prefix. 

Now, allocate that extra space in case we need it when we look up 
a legacy table to get its file's name.


mysql-test/r/drop.result:
  Verify that databases with old-style files can be removed.
mysql-test/t/drop.test:
  Verify that databases with old-style files can be removed.
sql/sql_db.cc:
  Extend the size of the memory that holds the table's name, so that
  the legacy "mysql50" prefix fits.

1 files changed, 7 insertions, 2 deletions

diff --git a/sql/sql_db.cc b/sql/sql_db.cc
index d03ac7921ac..75f9f5e847d 100644
--- a/sql/sql_db.cc
+++ b/sql/sql_db.cc
@@ -1111,12 +1111,17 @@ static long mysql_rm_known_files(THD *thd, MY_DIR *dirp, const char *db,
       /* Drop the table nicely */
       *extension= 0;			// Remove extension
       TABLE_LIST *table_list=(TABLE_LIST*)
-	thd->calloc(sizeof(*table_list)+ strlen(db)+strlen(file->name)+2);
+                              thd->calloc(sizeof(*table_list) + 
+                                          strlen(db) + 1 +
+                                          MYSQL50_TABLE_NAME_PREFIX_LENGTH + 
+                                          strlen(file->name) + 1);
+
       if (!table_list)
-	goto err;
+        goto err;
       table_list->db= (char*) (table_list+1);
       table_list->table_name= strmov(table_list->db, db) + 1;
       VOID(filename_to_tablename(file->name, table_list->table_name,
+                                 MYSQL50_TABLE_NAME_PREFIX_LENGTH +
                                  strlen(file->name) + 1));
       table_list->alias= table_list->table_name;	// If lower_case_table_names=2
       table_list->internal_tmp_table= is_prefix(file->name, tmp_file_prefix);