tests/sitecustomize.py

phases: apply similar early filtering to advanceboundary

advanceboundary is called the push's unbundle (but not the other unbundle) so
advanceboundary did not show up the profile I looked at so far.

We start with simple pre-filtering to avoid doing any work if we don't needs
too.

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