Google App Engine。 TextProperty重置为“”

Question

I run a small video game. Each player has an account model with a variety of properties.

I recently added a TextProperty to track player badges. These are just an ASCII character that is appended to the account.badges property as they are awarded.

Because the properly is new, most account models don't have this property. In about 3 places throughout the site I have some code that looks like this

if not player.badges:
  player.badges = ""

player.badges += "A"
player.put_memcache()
player.put()

For some reason, one of the players badges keeps getting reset to "" (empty string). I can't for the life of me work out how or why.

I've not worked with TextProperties before. Is there some strange behaviour I don't understand?

Do TextProperties not play nice with the memcache?

The account is not getting reset to some old state because other properties seem to be storing values correctly. Its just this one TextProperty.

Anyhow, I'm confused and would appreciated some fresh ideas that would help me track down the issue.

Question Answers

The badges propery is just defined like this

class Account(db.Model):

    badges = db.TextProperty()

    email = db.StringProperty()
    alias = db.StringProperty()
    avatar = db.IntegerProperty()

put_memchche is just a wrapper around memcache set.

def put_memchche(self):
    memcache.set("account" + self.key().name(), self)

Answer 1

AFAIK, text is similar to string, the difference is just text can contain more character and cannot be indexed. If you specify the default to "" I think you do not need the if part. Is it only happen for one player? Are you sure on runtime it hits the player.badges += 'A'. It would be easier to debug if you provide more code, based on your example, I don't see a problem why badges do not changed.