tests/sitecustomize.py

rust-index: avoid some cloning in find_gca_candidates()

Instead of keeping the information whether the current revision is
poisoned on `current_seen`, we extract it as a boolean.

This also allows us to simplify the explanation of `seen[r].is_poisoned()`,
as the exceptional case where it is poisoned right after `r` has been
determined to be a solution does no longer exist.

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