tests/sitecustomize.py

pytype: stop excluding upgrade.py

The sole failure here was this, which is fixed by simply creating a set like the
caller, instead of a dict:

  File "/mnt/c/Users/Matt/hg/mercurial/upgrade.py", line 73, in upgraderepo:
      No attribute 'discard' on Dict[nothing, nothing] [attribute-error]
    In Union[Any, Dict[nothing, nothing]]

Differential Revision: https://phab.mercurial-scm.org/D11911

from __future__ import absolute_import
import os

if os.environ.get('COVERAGE_PROCESS_START'):
    try:
        import coverage
        import uuid

        covpath = os.path.join(
            os.environ['COVERAGE_DIR'], 'cov.%s' % uuid.uuid1()
        )
        cov = coverage.coverage(data_file=covpath, auto_data=True)
        cov._warn_no_data = False
        cov._warn_unimported_source = False
        cov.start()
    except ImportError:
        pass