phases: avoid a potentially costly dictionary interation in some case
If we retract for the draft phase, there is not non-public item to be retracted
and we can skip this part. This part is was apparently super costly thanks to
Python.
On mozilla-try-2019-02-18, a perf::unbundle call with a 10 000 changesets
bundle gives give use the following timing.
e57d4b868a3e: 4.6 seconds
ac1c75188440: 102.5 seconds
this-changeset: 30.0 seconds
So we recovered about ⅔ of the regression, the next changeset will give us the
rest back.
#!/usr/bin/env python3
#
# Based on python's Tools/scripts/md5sum.py
#
# This software may be used and distributed according to the terms
# of the PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2, which is
# GPL-compatible.
import hashlib
import os
import sys
try:
import msvcrt
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
pass
for filename in sys.argv[1:]:
try:
fp = open(filename, 'rb')
except IOError as msg:
sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg))
sys.exit(1)
m = hashlib.md5()
try:
for data in iter(lambda: fp.read(8192), b''):
m.update(data)
except IOError as msg:
sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))
sys.exit(1)
sys.stdout.write('%s %s\n' % (m.hexdigest(), filename))
sys.exit(0)