Issue with implementation_name env marker on py34

[andy-maier]

On Python 3.4 with minimum package levels, make installtest fails because Pip stumbles across the use of the implementation_name env marker in dev-requirements.txt and minimum-constraints.txt that was introduced with PR #2200 on the typed-ast package:

makefile: Running install tests
tests/installtest/test_install.sh dist/pywbem-1.0.0.dev1-py2.py3-none-any.whl dist/pywbem-1.0.0.dev1.tar.gz python
Preparing for the tests
Creating test directory: tests/installtest/../../tmp_installtest
Creating source archive unpack directory: tests/installtest/../../tmp_installtest/src_dist
Removing .egg file: tests/installtest/../../dist/pywbem*.egg
Testcase test1: Pip install from repo root directory: tests/installtest/../..
Saving current virtualenv: /home/travis/virtualenv/python3.4.8
Creating virtualenv: tests/installtest/../../tmp_installtest/virtualenvs/pywbem_test_test1
..using this Python command: /home/travis/virtualenv/python3.4.8/bin/python
..that has this Python version: Python 3.4.8
Activating virtualenv: tests/installtest/../../tmp_installtest/virtualenvs/pywbem_test_test1
Python command in this virtualenv: /home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/bin/python
Python version in this virtualenv: Python 3.4.8
Packages in this virtualenv before reinstalling base packages:
pip (8.0.0)
setuptools (19.4)
wheel (0.26.0)
Reinstalling setuptools with PACKAGE_LEVEL=minimum
Error: Command failed with rc=2: pip install setuptools -c /home/travis/build/pywbem/pywbem/minimum-constraints.txt, output follows:
Ignoring pip: markers "python_version == '3.6'" don't match your environment
Ignoring pip: markers "python_version == '3.7'" don't match your environment
Ignoring pip: markers "python_version >= '3.8'" don't match your environment
Ignoring setuptools: markers "python_version == '3.7'" don't match your environment
Ignoring setuptools: markers "python_version >= '3.8'" don't match your environment
Ignoring wheel: markers "python_version == '3.7'" don't match your environment
Ignoring wheel: markers "python_version >= '3.8'" don't match your environment
Ignoring PyYAML: markers "python_version == '2.7'" don't match your environment
Ignoring six: markers "python_version >= '3.8'" don't match your environment
Ignoring funcsigs: markers "python_version < '3.3'" don't match your environment
Ignoring pytest: markers "python_version >= '3.7'" don't match your environment
Ignoring colorama: markers "python_version >= '3.5'" don't match your environment
Ignoring virtualenv: markers "python_version >= '3.5' and python_version < '3.8'" don't match your environment
Ignoring virtualenv: markers "python_version >= '3.8'" don't match your environment
Ignoring pluggy: markers "python_version >= '3.7'" don't match your environment
Ignoring lxml: markers "python_version >= '3.8'" don't match your environment
Ignoring pylint: markers "python_version == '2.7'" don't match your environment
Ignoring pylint: markers "python_version >= '3.5'" don't match your environment
Ignoring astroid: markers "python_version == '2.7'" don't match your environment
Ignoring astroid: markers "python_version >= '3.5'" don't match your environment
Exception:
Traceback (most recent call last):
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/basecommand.py", line 209, in main
    status = self.run(options, args)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/commands/install.py", line 287, in run
    wheel_cache
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/basecommand.py", line 264, in populate_requirement_set
    requirement_set.add_requirement(req)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/req/req_set.py", line 224, in add_requirement
    if not install_req.match_markers():
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/req/req_install.py", line 799, in match_markers
    return markers_interpret(self.markers)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 190, in interpret
    return Evaluator(execution_context).evaluate(marker.strip())
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 100, in evaluate
    return handler(node)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 163, in do_expression
    return self.evaluate(node.body)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 100, in evaluate
    return handler(node)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 127, in do_boolop
    result = self.evaluate(n)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 100, in evaluate
    return handler(node)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 147, in do_compare
    lhs = self.evaluate(lhsnode)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 100, in evaluate
    return handler(node)
  File "/home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/lib/python3.4/site-packages/pip/_vendor/distlib/markers.py", line 174, in do_name
    raise SyntaxError('invalid expression: %s' % node.id)
  File "<string>", line None
SyntaxError: invalid expression: implementation_name
makefile:693: recipe for target 'installtest' failed

[andy-maier]

Pip 8.0.0 that is used in that virtualenv does not yet have support for implementation_name. Pip 9.0.1 does. That suggests to first upgrade pip in test_installed.sh. The reason why test_installed.sh first installs setuptools and then pip is that in an earlier run, installing pip first caused a permission error. Trying again with order pip first.

[andy-maier]

This isssue was fixed by removing the marker and installing pip first.

After fixing it, a second issue showed up on Python 3.4 with latest package levels, where pip was not installed into the virtualenv created by test_install.sh. Created virtualenv issue pypa/virtualenv#1809 for that. This could be circumvented by pinning virtualenv to 20.0.18 on py<3.5.

Both fixes and some more diagnostic output in test_install.sh are in PR #2215 for master. No rollback to 0.17 since the marker was not used there.

[andy-maier]

Virtualenv 20.0.20 fixes the reported issue.
Changed PR #2215 to no longer pin virtualenv to <20.0.19 but to just exclude 20.0.19.