Travis CI: Test Python 3.8

[hugovk]

Python 3.8.0 final is now available on Travis CI as 3.8.

Follows on from #7219.

For #7229.

[hugovk]

The vendoring job, now on 3.8, is failing and I'm not entirely sure why. Any ideas?

  Installing build dependencies: started
  Installing build dependencies: still running...
  Installing build dependencies: finished with status 'error'
  ERROR: Command errored out with exit status 1:
   command: /home/travis/build/pypa/pip/.tox/vendoring/bin/python /home/travis/build/pypa/pip/.tox/vendoring/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-72o4mrvy/overlay --no-warn-script-location --no-binary :all: --only-binary :none: -i https://pypi.org/simple -- flit
       cwd: None
  Complete output (53 lines):
  Collecting flit
    Downloading https://files.pythonhosted.org/packages/1f/87/9ea76ab4cdf1fd36710d9688ec36a0053067c47e753b32272f952ff206c5/flit-1.3.tar.gz (92kB)
    Installing build dependencies: started
    Installing build dependencies: finished with status 'done'
    Getting requirements to build wheel: started
    Getting requirements to build wheel: finished with status 'done'
    Installing backend dependencies: started
    Installing backend dependencies: finished with status 'done'
      Preparing wheel metadata: started
      Preparing wheel metadata: finished with status 'done'
  Collecting pytoml (from flit)
    Using cached https://files.pythonhosted.org/packages/f4/ba/98ee2054a2d7b8bebd367d442e089489250b6dc2aee558b000e961467212/pytoml-0.1.21.tar.gz
  Collecting requests (from flit)
    Using cached https://files.pythonhosted.org/packages/01/62/ddcf76d1d19885e8579acb1b1df26a852b03472c0e46d2b959a714c90608/requests-2.22.0.tar.gz
  Collecting docutils (from flit)
    Using cached https://files.pythonhosted.org/packages/93/22/953e071b589b0b1fee420ab06a0d15e5aa0c7470eb9966d60393ce58ad61/docutils-0.15.2.tar.gz
  Collecting chardet<3.1.0,>=3.0.2 (from requests->flit)
    Using cached https://files.pythonhosted.org/packages/fc/bb/a5768c230f9ddb03acc9ef3f0d4a3cf93462473795d18e9535498c8f929d/chardet-3.0.4.tar.gz
  Collecting idna<2.9,>=2.5 (from requests->flit)
    Using cached https://files.pythonhosted.org/packages/ad/13/eb56951b6f7950cadb579ca166e448ba77f9d24efc03edd7e55fa57d04b7/idna-2.8.tar.gz
  Collecting urllib3!=1.25.0,!=1.25.1,<1.26,>=1.21.1 (from requests->flit)
    Using cached https://files.pythonhosted.org/packages/ff/44/29655168da441dff66de03952880c6e2d17b252836ff1aa4421fba556424/urllib3-1.25.6.tar.gz
  Collecting certifi>=2017.4.17 (from requests->flit)
    Using cached https://files.pythonhosted.org/packages/62/85/7585750fd65599e88df0fed59c74f5075d4ea2fe611deceb95dd1c2fb25b/certifi-2019.9.11.tar.gz
  Skipping bdist_wheel for flit, due to binaries being disabled for it.
  Installing collected packages: pytoml, chardet, idna, urllib3, certifi, requests, docutils, flit
    Running setup.py install for pytoml: started
      Running setup.py install for pytoml: finished with status 'done'
    Running setup.py install for chardet: started
      Running setup.py install for chardet: finished with status 'done'
    Running setup.py install for idna: started
      Running setup.py install for idna: finished with status 'done'
    Running setup.py install for urllib3: started
      Running setup.py install for urllib3: finished with status 'done'
    Running setup.py install for certifi: started
      Running setup.py install for certifi: finished with status 'done'
    Running setup.py install for requests: started
      Running setup.py install for requests: finished with status 'done'
    Running setup.py install for docutils: started
      Running setup.py install for docutils: finished with status 'done'
    Running setup.py install for flit: started
      Running setup.py install for flit: finished with status 'error'
      ERROR: Command errored out with exit status 1:
       command: /home/travis/build/pypa/pip/.tox/vendoring/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-m8m1f9wv/flit/setup.py'"'"'; __file__='"'"'/tmp/pip-install-m8m1f9wv/flit/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-bgg5jvoz/install-record.txt --single-version-externally-managed --prefix /tmp/pip-build-env-72o4mrvy/overlay --compile --install-headers /home/travis/build/pypa/pip/.tox/vendoring/include/site/python3.8/flit
           cwd: /tmp/pip-install-m8m1f9wv/flit/
      Complete output (3 lines):
      Traceback (most recent call last):
        File "<string>", line 1, in <module>
      ModuleNotFoundError: No module named 'setuptools'
      ----------------------------------------
  ERROR: Command errored out with exit status 1: /home/travis/build/pypa/pip/.tox/vendoring/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-m8m1f9wv/flit/setup.py'"'"'; __file__='"'"'/tmp/pip-install-m8m1f9wv/flit/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-bgg5jvoz/install-record.txt --single-version-externally-managed --prefix /tmp/pip-build-env-72o4mrvy/overlay --compile --install-headers /home/travis/build/pypa/pip/.tox/vendoring/include/site/python3.8/flit Check the logs for full command output.
  WARNING: You are using pip version 19.2.3, however version 19.3 is available.
  You should consider upgrading via the 'pip install --upgrade pip' command.
  ----------------------------------------
ERROR: Command errored out with exit status 1: /home/travis/build/pypa/pip/.tox/vendoring/bin/python /home/travis/build/pypa/pip/.tox/vendoring/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-72o4mrvy/overlay --no-warn-script-location --no-binary :all: --only-binary :none: -i https://pypi.org/simple -- flit Check the logs for full command output.
WARNING: You are using pip version 19.2.3, however version 19.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
ERROR: InvocationError for command /home/travis/build/pypa/pip/.tox/vendoring/bin/invoke vendoring.update (exited with code 1)
___________________________________ summary ____________________________________
ERROR:   vendoring: commands failed
The command "tools/travis/run.sh" exited with 1.

[chrahunt]

The corresponding logs from a previous build show:

...
  Missing build time requirements in pyproject.toml for pep517==0.7.0 from https://files.pythonhosted.org/packages/a9/17/0b2944c9e5d2415b78e5aac55aaa2a5aef916ccdd2a085c44f294d6f182c/pep517-0.7.0.tar.gz#sha256=d283181fdb83fb698556cd3a4ebde5bb352b59242574e6ca56a95118774da374 (from -r /home/travis/build/pypa/pip/src/pip/_vendor/vendor.txt (line 11)): 'setuptools' and 'wheel'.
  This version of pip does not implement PEP 517 so it cannot build a wheel without 'setuptools' and 'wheel'.
  Installing build dependencies: started
  Installing build dependencies: finished with status 'done'
...
Successfully downloaded appdirs CacheControl colorama contextlib2 distlib distro html5lib ipaddress msgpack packaging pep517 progress pyparsing pytoml requests certifi chardet idna urllib3 retrying setuptools six webencodings
You are using pip version 10.0.1, however version 19.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

So probably this is another example of #6222, and the pip bundled with the previous Python was old enough to not have this issue.

[hugovk]

Thanks! Whilst the PR to fix that (#6606) is awaiting review, I've made PR #7224.

[chrahunt]

#6606 was merged, but this is also blocked on actions/setup-python#30 (so the docs build can have 1 python mentioned in config)

[pradyunsg]

I don't think we should block broader CI testing for 3.8 on the fact that 3.8 isn't available for docs builds. This is especially true since Read The Docs is the blocker in that scenario, not Travis or GitHub Actions.

[hugovk]

@pradyunsg Agreed, please see #7224 which basically flips 3.8-dev to 3.8 final, and moves them up in the list. No changes to the base Python for docs etc.

[hugovk]

#6606 was merged, but this is also blocked on actions/setup-python#30 (so the docs build can have 1 python mentioned in config)

Python 3.8 is now available on GitHub Actions: actions/setup-python#30 (comment).

[BrownTruck]

Hello!

I am an automated bot and I have noticed that this pull request is not currently able to be merged. If you are able to either merge the master branch into this pull request or rebase this pull request against master then it will be eligible for code review and hopefully merging!

[chrahunt]

Added pip>=19.3.1 requirement to the vendoring dependencies which has #6606.

[chrahunt]

Thanks for sticking with this @hugovk!

[hugovk]

And thanks for vendoring fix!