[BUG] Wrong encoding detected for empty JSON response

[tseaver]

Describe the bug

requests 2.26.0 switched to using charset_normalizer by default under Python 3 (see: googleapis/python-cloud-core#117). After this change, a response constructed with an empty JSON body (b"{}) can no longer unmarshall to the empty dict in its json method.

To Reproduce

>>> import charset_normalizer
>>> empty_json_response = b"{}"
>>> detected = charset_normalizer.detect(empty_json_response)
....nox/unit-3-6/lib/python3.6/site-packages/charset_normalizer/api.py:95: UserWarning: Trying to detect encoding from a tiny portion of (2) byte(s).
  warn('Trying to detect encoding from a tiny portion of ({}) byte(s).'.format(length))
>>> detected
{'encoding': 'utf_16_be', 'language': '', 'confidence': 1.0}
>>> decoded = empty_json_response.decode(detected["encoding"])
>>> decoded
'筽'
>>> import json
>>> json.loads(decoded)
/opt/Python-3.6.10/lib/python3.6/json/__init__.py:354: in loads
    return _default_decoder.decode(s)
/opt/Python-3.6.10/lib/python3.6/json/decoder.py:339: in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <json.decoder.JSONDecoder object at 0x7fd0b5810860>, s = '筽', idx = 0

    def raw_decode(self, s, idx=0):
        """Decode a JSON document from ``s`` (a ``str`` beginning with
        a JSON document) and return a 2-tuple of the Python
        representation and the index in ``s`` where the document ended.
    
        This can be used to decode a JSON document from a string that may
        have extraneous data at the end.
    
        """
        try:
            obj, end = self.scan_once(s, idx)
        except StopIteration as err:
>           raise JSONDecodeError("Expecting value", s, err.value) from None
E           json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Expected behavior
I expect to be able unmarshall b"{}" into an empty dict, {}.

Desktop (please complete the following information):

• OS: Linux
• Python version: 3.6, 3.7, 3.8, 3.9
• Package version: 2.0.1

[Ousret]

Hi @tseaver

Thanks for the report,
I was able to reproduce this easily. The miss-detect fault happen in the plugin TooManySymbolOrPunctuationPlugin(MessDetectorPlugin).
Adjustments are to be done in this plugin.

[Ousret]

The following PR should fix your issue #59
If you have any more concerns, do not hesitate.

[Ousret]

Now available under https://github.com/Ousret/charset_normalizer/releases/tag/2.0.2