This is technically wrong. The documentation states that:
"Note that None may be returned if no handler handles the request
(though the default installed global OpenerDirector uses
UnknownHandler to ensure this never happens)."
This is super marginal and making it optional causes a few dozen
errors in an internal dropbox code base.
* HTTP Handler class annotations for py2/urllib2 & py3/urllib.request
Add full annotations for the following classes:
* Python 2:
* `urllib2.AbstractHTTPHandler`
* `urllib2.HTTPHandler`
* `urllib2.HTTPsHandler`
* Python 3:
* `urllib.request.AbstractHTTPHandler`
* `urllib.request.HTTPHandler`
* `urllib.request.HTTPsHandler`
This information is largely undocumented, and was obtained by directly examining
the Python source code:
* Python 2 (v2.7.15) - https://github.com/python/cpython/blob/v2.7.15/Lib/urllib2.py#L1115-L1243
* Python 3 (v3.7.1) - https://github.com/python/cpython/blob/v3.7.1/Lib/urllib/request.py#L1224-L1364
`urllib2.AbstractHTTPHandler.do_open` takes as a parameter either
`HTTPConnection` or `HTTPSConnection`--one of the classes, not an instance of
either--and constructs an object using only a few of the parameters that either
constructor could use. `HTTPConnectionProtocol` in `stdlib/2/httplib.pyi`
follows a similar patten to `HTTPConnectionProtocol` added to
`stdlib/3/http/client.pyi` in pull request #2582 to describe the type of the
`http_class` that is passed to `do_open`.
It seems that code using HTTPError previously worked by accident
because we used to accept arbitrary keyword arguments when
instantiating BaseException, or any subclass of BaseException
(see https://github.com/python/typeshed/pull/2348).
This commit adds in the correct constructor (which also lets the
user specify the arguments in keyword-argument form).
Note: I'm not very familiar with the urllib libraries, so I opted
to just add the signature and leave it up to somebody else to
fill in the types.
* Add flags to pass on --warn-unused-ignores and --no-implicit-optional to mypy
* Make implicit Optional explicit in arg types (2and3 part)
* Convert {stdlib,third_party}/2 to explicit Optional
Michael Lee