Dictionary extraction such as c = {**a, **b} not functioning properly.

[heetbeet]

The following was tested on Linux Mint 17, Python version Python 3.6.2 :: Anaconda custom (64-bit) and dotmap version sys.version_info(major=3, minor=6, micro=2, releaselevel='final', serial=0)

1. (lambda **x:x)(**DotMap(a=1)) returns an unexpected empty dictionary {},
2. {**DotMap(a=1),**DotMap(b=2)} returns an unexpected empty dictionary {}, and
3. m = DotMap(); m.a = 2; m.b = 3; print('{a} {b}'.format(**m)); fails with KeyError: 'a'.

Other functionality is working properly such as:

1. DotMap(a=1)['a'] returns an expected 1, and
2. DotMap(a=1).a returns an expected 1.

[drgrib]

@heetbeet I'm not able to reproduce item 3, but I can reproduce 1 and 2.

The issue seems to be that, because DotMap inherits from OrderedDict, its own implementations for

• __len__
• __iter__
• __getitem__

are being ignored in these particular types of ** calls and instead being called for the parent OrderedDict class.

I can fix your cases by removing that inheritance and only having it inherit from MutableMapping but that breaks a unit test in __main__ with the title == copy order preservation ==.

If you have immediate suggestions, I'm open to them. Otherwise, I'll have to debug this at a later time.

[heetbeet]

@drgrib I see. I switched over to the following implementation for my dot dictionary needs (I know it clashes for keys that are the same as the dictionary names - such as "pop", "update", "keys", "values", etc.):

class DotDict(dict):
    def __init__(self, **kwds):
        self.update(kwds)
        self.__dict__ = self

So I am not in an immediate need for fixes. I'll switch back to DotMap in the future when doing a bit of code refactoring and the pip default is working nicely again. Thanks for the trouble.

[remcoboerma]

Shortest test on python2.7.13 for this issue:

>>> dict(**dotmap.DotMap(a=1))
{}

When using ** a lot this means DotMap fails as a dropin replacement for dictionaries. And it would be so nice to have just that.

[drgrib]

I've given this multiple shots and it's honestly too complicated to be worth the trouble when there is a simple workaround available already:

>>> dict(**dotmap.DotMap(a=1).toDict())
{'a': 1}

More on why completely acing the subclass in this manner is so difficult here.

[drgrib]

Fixed in #53