Update to v2.8.6 without release

- Code refactoring
- Update the song database
- Fix a bug of the friend system which arose in the last version
- Fix a bug of duplicate calculating finishing states when players finish playing the chart in Link Play.

latest version/core/sql.py

@@ -20,14 +20,17 @@ class Connect():
         return self.c
 
     def __exit__(self, exc_type, exc_val, exc_tb):
+        if exc_type is not None:
+            if self.conn:
+                self.conn.rollback()
+
+            current_app.logger.error(
+                traceback.format_exception(exc_type, exc_val, exc_tb))
+
         if self.conn:
             self.conn.commit()
             self.conn.close()
 
-        if exc_type is not None:
-            current_app.logger.error(
-                traceback.format_exception(exc_type, exc_val, exc_tb))
-
         return True