revlog: improve documentation of the entry tuple
The code in revlog, and outside revlog directly use the index's entry tuple,
with direct integer indexing. This is a voluntary trade off to obtains better
performance from the Python code at the expense of the developers sanity.
Let's at least have a clear and central documentation about what this tuple is
about.
Differential Revision: https://phab.mercurial-scm.org/D10643
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