1. Removed module self test in favor of unittests -- Timbot's suggestion.
2. Replaced calls to Set([]) with Set() -- Timbot's suggestion
3. Fixed subtle bug in sets of sets:
The following code did not work (will add to test suite):
d = Set('d')
s = Set([d]) # Stores inner set as an ImmutableSet
s.remove(d) # For comparison, wraps d in _TemporarilyImmutableSet
The comparison proceeds by computing the hash of the
_TemporarilyImmutableSet and finding it in the dictionary.
It then verifies equality by calling ImmutableSet.__eq__()
and crashes from the binary sanity check.
The problem is that the code assumed equality would be checked
with _TemporarilyImmutableSet.__eq__().
The solution is to let _TemporarilyImmutableSet derive from BaseSet
so it will pass the sanity check and then to provide it with the
._data element from the wrapped set so that ImmutableSet.__eq__()
will find ._data where it expects.
Since ._data is now provided and because BaseSet is the base class,
_TemporarilyImmutableSet no longer needs .__eq__() or .__ne__().
Note that inheriting all of BaseSet's methods is harmless because
none of those methods (except ones starting with an underscore)
can mutate the .data element. Also _TemporarilyImmutableSet is only
used internally as is not otherwise visible.
1 file changed