stop using deprecated HTMLParser.unescape

[methane]

Summary of changes

HTMLParser.unescape is deprecated since Python 3.4.

Pull Request Checklist

• N/A Changes have tests
• News fragment added in changelog.d. See documentation for details

[methane]

Should this type of change require News fragment and test?

Note that this change is executed always when this module is imported...

[pganssle]

It took me a second to realize how this was different from the current formulation, but it's because as is, HtmlParser().unescape is always executed, even if unused.

I think a changelog entry would be wise, because when people start using Python 3.9, they'll want to know the minimum version of setuptools to pin.

I don't think a separate test for this is necessary.

Thanks!

[pganssle]

Thanks @methane, I've squashed the current commits and marked this for auto-merge, so it should merge as soon as the CI passes.

Glad to have people getting us ahead of the curve on avoiding deprecation warnings / breaking changes. Much better for the versions of setuptools that work with Python 3.9 to be released well in advance of 3.9.

[GegX]

I encounter that issue with python 3.9 while installing
python3 -m pip install robotframework-debugger
so this would do the trick

´´´
Collecting tkinterhtml (from robotframework-debugger)
Downloading https://files.pythonhosted.org/packages/37/be/86c2db091f663667686726aa7c45dc5fa198683b018986e6a5854006dbd7/tkinterhtml-0.7.zip (930kB)
100% |████████████████████████████████| 931kB 1.9MB/s
Exception:
File "/usr/share/python-wheels/setuptools-39.0.1-py2.py3-none-any.whl/setuptools/py33compat.py", line 54, in
unescape = getattr(html, 'unescape', html_parser.HTMLParser().unescape)
AttributeError: 'HTMLParser' object has no attribute 'unescape
´´´

my params:
setuptools-50.3.2
python 3.9.0
pip 9.0.1

[methane]

What version of setuptools do you use?
Don't you just using very old setuptools?

[joergent]

The file py33compat.py is buggy placing the test for the html module in the bottom of the file probably inside a class where the html module import is hidden and not just after importing html. This is my interpretation as I don't program in python.
However the py33compat.py file is omitted in version 51.0.0 and the wrong test for html.unescape is thus history.

This incorrect test prevented me in using letsencrypt as it was upgrading itself automatically.
I changed the setuptool lines in certbot-auto to this

('12/e1/b9a2926a3c5a3fb055b8f85052f5baa890106a0e21b64a977c10affea751/'
'setuptools-51.0.0.zip',
'029c49fd713e9230f6a41c0298e6e1f5839f2cde7104c0ad5e053a37777e7688'),