MUST NOT send Transfer-Encoding or Content-Length for 1xx or 204

[alexanderlukanin13]

Fixes #165

[digitalresistor]

Also fixes/closes: #152

[mmerickel]

This fix does not affect the content-length at all so I think #152 is still valid but probably needs to be fixed in webob, not waitress.

[digitalresistor]

Do we have a test that will verify waitress will not send any content even if the WSGI app returns a body for the 204 and that we still close the iterator correctly (even if we don't iterate over it)?

[digitalresistor]

You may be correct @mmerickel. Need to verify.

[tseaver]

Also needs a test for a 10x status.

[digitalresistor]

There is a test for if the status code starts with 1.

[tseaver]

@bertjwregeer I'm talking about branch coverage: the PR does not add a new testcase for the 10x status code, only for 204. It also doesn't update any existing testcases which might have triggered the same branch.

[alexanderlukanin13]

@tseaver @bertjwregeer Added test for HTTP 1xx (specifically 100 Continue) code. Test is the same as for 204. If you want more in-depth testing, please ask someone with a good knowledge of waitress.

[tseaver]

I would be included to factor the test into a self.no_body() method, and then test that for the different status codes.

[digitalresistor]

@mmerickel That's not an issue in WebOb.

The issue is related to how Waitress deals with responses that don't contain a Content-Length header:

def test_execute_app_returns_204_no_content_without_cl(self):
        def app(environ, start_response):
            start_response('204 No Content', [])
            return [b'']

        inst = self._makeOne()
        inst.channel.server.application = app
        inst.execute()
        self.assertEqual(inst.content_length, None)

======================================================================
FAIL: test_execute_app_returns_204_no_content_without_cl (waitress.tests.test_task.TestWSGITask)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/xistence/Projects/waitress/waitress/tests/test_task.py", line 486, in test_execute_app_returns_204_no_content_without_cl
    self.assertEqual(inst.content_length, None)
AssertionError: 0 != None

[digitalresistor]

@alexanderlukanin13 do you have time to incorporate the changes that @tseaver requested?

[digitalresistor]

Thank you @alexanderlukanin13, I'll try and get some work done on this tonight!

[digitalresistor]

Please see #202 for a follow-up to this PR that includes a fix for the 304 issue and goes a step further to make sure we don't accidentally send a further response than expected.