Bootstrapping pants_deps with requirements:
  /Users/eax/svn/pants/3rdparty/python/requirements.txt
  /Users/eax/svn/pants/3rdparty/python/twitter/commons/requirements.txt
  /Users/eax/svn/pants/pants-plugins/3rdparty/python/requirements.txt
  /Users/eax/svn/pants/contrib/python/src/python/pants/contrib/python/checks/checker/3rdparty/requirements.txt
Using python at /usr/bin/python3
Using base prefix '/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.7'
New python executable in /Users/eax/svn/pants/build-support/virtualenvs/Darwin/pants_dev_deps.py37.venv/bin/python3
Also creating executable in /Users/eax/svn/pants/build-support/virtualenvs/Darwin/pants_dev_deps.py37.venv/bin/python
Traceback (most recent call last):
  File "/Users/eax/svn/pants/build-support/virtualenv.dist/virtualenv.py", line 2619, in <module>
    main()
  File "/Users/eax/svn/pants/build-support/virtualenv.dist/virtualenv.py", line 867, in main
    symlink=options.symlink,
  File "/Users/eax/svn/pants/build-support/virtualenv.dist/virtualenv.py", line 1142, in create_environment
    install_python(home_dir, lib_dir, inc_dir, bin_dir, site_packages=site_packages, clear=clear, symlink=symlink)
  File "/Users/eax/svn/pants/build-support/virtualenv.dist/virtualenv.py", line 1607, in install_python
    shutil.copy(original_python, py_executable)
  File "/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/shutil.py", line 245, in copy
    copyfile(src, dst, follow_symlinks=follow_symlinks)
  File "/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/shutil.py", line 103, in copyfile
    if _samefile(src, dst):
  File "/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/shutil.py", line 88, in _samefile
    return os.path.samefile(src, dst)
  File "/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/genericpath.py", line 96, in samefile
    s1 = os.stat(f1)
TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType`