The pure Python implementation of _dict_to_bson in fact accepts
arbitrary mapping types, while the C implementation only accepts
mapping types based on `dict`.
The attached BUG-arbitrary-mapping.patch (see
https://github.com/wolfmanx/mongo-python-driver/commit/6eb4cc47e35c3fc8bb17a81bf9189c3d4fa7b4a4)
provides a possible solution that allows to enable/disable this feature.
IMHO, the default should be either to break existing code or at list
issue a warning, since there is no easy way to fix code, that depends
on the behavior of the pure Python implementation and suddenly won't
run with the C extension enabled.
With the following test case in test_zz_bson.py (see attachment, only
excerpt shown here)::
class TestBSON(unittest.TestCase):
def setUp(self):
pass
def test_arbitrary_mapping_type(self):
class ArbitrayMapping(object):
def __init__(self):
self._arbitrary_mapping_dict_ = dict()
def __getattr__(self, attr):
try:
return getattr(self._arbitrary_mapping_dict_, attr)
except AttributeError:
return super(ArbitrayMapping, self).__getattribute__(attr)
def __iter__(self):
return self._arbitrary_mapping_dict_.__iter__()
def __getitem__(self, key):
return self._arbitrary_mapping_dict_.__getitem__(key)
def __setitem__(self, key, val):
return self._arbitrary_mapping_dict_.__setitem__(key, val)
am = ArbitrayMapping()
self.assertRaises(TypeError, BSON.encode, am)
am['_id'] = 'FFFFFFFFFFFFFFFFFFFFFFFF'
self.assertRaises(TypeError, BSON.encode, am)
Running the test with the C extension, a `TypeError` is raised, since
_cbson._dict_to_bson only accepts real `dict` objects. Therefore,
the test passes::
$ python setup.py test -s test.test_zz_bson test_arbitrary_mapping_type (test.test_zz_bson.TestBSON) ... ok
But without the C Extension, the test fails, since the Python version
of _dict_to_bson indeed accepts arbitrary mapping types::
$ find -name '*.so' | xargs -r rm; python setup.py --without-c-ext test -s test.test_zz_bson
test_arbitrary_mapping_type (test.test_zz_bson.TestBSON) ... FAIL
======================================================================
FAIL: test_arbitrary_mapping_type (test.test_zz_bson.TestBSON)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/ws/project/ws-util/mongodb/pymongo/mongo-python-driver-git/test/test_zz_bson.py", line 85, in test_arbitrary_mapping_type
self.assertRaises(TypeError, BSON.encode, am)
AssertionError: TypeError not raised
----------------------------------------------------------------------
- is depended on by
-
PYTHON-505 Allow PyMongo to work with any object that implements mapping protocol, not just dicts
-
- Closed
-