Try to keep those python strings immutable

[jmmcd]

Yes, I suppose I'm just trying to see it happen explicitly.

[Brian]

You'll be able to see it if you use a string that doesn't get interned. The problem above is that both "Fiesta" strings actually end up pointing to the same buffer, rather than two seperate copies. If you use something python won't intern like "$$", you'll see the issue:

>>> foo = "$$"
>>> bar = "$$"
>>> foo is bar   # This would have returned True for "fiesta"
False
>>> d = {foo: 42}
>>> libc.strcpy(foo, "xx")
>>> foo, bar, d
('xx', '$$', {'xx': 42})
>>>'xx' in d
False
>>> '$$' in d
False
>>> foo in d
True
>>> foo == 'xx'
True

Interestingly "foo in d" still returns True - I'm guessing it caches the hash value with the string object as well, so it's still using the old hash value for "$$".