set command can overwrite data structure of hash

[han-ian]

May be this is a bug.

How to reporduce the test:

Diving into the code, can see that string and hash meta key has the same key format. For the set command, may be it need to check if there is a existing key ?

[han-ian]

If this is a bug, I guess the sub_key may be out of control because the meta_key is lost.