merge: rework manifestmerge to use a matcher
This opens the door to working slightly more closely with the manifest
type and letting it optimize out some of the diff comparisons for us,
and also makes life significantly easier for narrowhg.
import os
if os.environ.get('COVERAGE_PROCESS_START'):
try:
import coverage
import random
# uuid is better, but not available in Python 2.4.
covpath = os.path.join(os.environ['COVERAGE_DIR'],
'cov.%s' % random.randrange(0, 1000000000000))
cov = coverage.coverage(data_file=covpath, auto_data=True)
cov._warn_no_data = False
cov._warn_unimported_source = False
cov.start()
except ImportError:
pass