Does it make sense to make Python 3 dict_keys serializable?

[msabramo]

I ran into an issue porting a project to Python 3, where simplejson raises a TypeError because of dict_keys:

  File "/Users/marca/dev/git-repos/cornice/.tox/py33/lib/python3.3/site-packages/simplejson/encoder.py", line 226, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: dict_keys([1, 2]) is not JSON serializable

This is easily fixed in the project by wrapping the dict_keys with list and that's fine, but I wonder if it makes sense to do it in simplejson as a convenience to make porting to Python 3 easier.

I could submit a PR if this is deemed useful, but I wanted to check first and make sure that this makes sense, wouldn't hurt performance too much, etc.

[etrepum]

Not sure this makes sense, it's the first time that this has come up.

I'd prefer not to add special cases for things like this unless there really was a lot of demand for it. Types like this are pretty opaque and it's hard to test for them.

[p3ngu1nx]

I have the same problem

[vsajip]

The encoding of dicts happens via iteration AFAIK, so is this a case where @msabramo, @boriza the code in question explicitly tries to encode the result of some_dict.keys(), rather than encoding some_dict?