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worker: Use buffered input from the pickle stream...
worker: Use buffered input from the pickle stream On Python 3, "pickle.load" will raise an exception ("_pickle.UnpicklingError: pickle data was truncated") when it gets a short read, i.e. it receives fewer bytes than it requested. On our build machine, Mercurial seems to frequently hit this problem while updating a mozilla-central clone iff it gets scheduled in batch mode. It is easy to trigger with: #wipe the workdir rm -rf * hg update null chrt -b 0 hg update default I've also written the following program, which demonstrates the core problem: from __future__ import print_function import io import os import pickle import time obj = {"a": 1, "b": 2} obj_data = pickle.dumps(obj) assert len(obj_data) > 10 rfd, wfd = os.pipe() pid = os.fork() if pid == 0: os.close(rfd) for _ in range(4): time.sleep(0.5) print("First write") os.write(wfd, obj_data[:10]) time.sleep(0.5) print("Second write") os.write(wfd, obj_data[10:]) os._exit(0) try: os.close(wfd) rfile = os.fdopen(rfd, "rb", 0) print("Reading") while True: try: obj_copy = pickle.load(rfile) assert obj == obj_copy except EOFError: break print("Success") finally: os.kill(pid, 15) The program reliably fails with Python 3.8 and succeeds with Python 2.7. Providing the unpickler with a buffered reader fixes the issue, so let "os.fdopen" create one. https://bugzilla.mozilla.org/show_bug.cgi?id=1604486 Differential Revision: https://phab.mercurial-scm.org/D8051

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genosxversion.py
136 lines | 4.1 KiB | text/x-python | PythonLexer
#!/usr/bin/env python2
from __future__ import absolute_import, print_function
import argparse
import os
import subprocess
import sys
# Always load hg libraries from the hg we can find on $PATH.
hglib = subprocess.check_output(['hg', 'debuginstall', '-T', '{hgmodules}'])
sys.path.insert(0, os.path.dirname(hglib))
from mercurial import util
ap = argparse.ArgumentParser()
ap.add_argument(
'--paranoid',
action='store_true',
help=(
"Be paranoid about how version numbers compare and "
"produce something that's more likely to sort "
"reasonably."
),
)
ap.add_argument('--selftest', action='store_true', help='Run self-tests.')
ap.add_argument('versionfile', help='Path to a valid mercurial __version__.py')
def paranoidver(ver):
"""Given an hg version produce something that distutils can sort.
Some Mac package management systems use distutils code in order to
figure out upgrades, which makes life difficult. The test case is
a reduced version of code in the Munki tool used by some large
organizations to centrally manage OS X packages, which is what
inspired this kludge.
>>> paranoidver('3.4')
'3.4.0'
>>> paranoidver('3.4.2')
'3.4.2'
>>> paranoidver('3.0-rc+10')
'2.9.9999-rc+10'
>>> paranoidver('4.2+483-5d44d7d4076e')
'4.2.0+483-5d44d7d4076e'
>>> paranoidver('4.2.1+598-48d1e1214d8c')
'4.2.1+598-48d1e1214d8c'
>>> paranoidver('4.3-rc')
'4.2.9999-rc'
>>> paranoidver('4.3')
'4.3.0'
>>> from distutils import version
>>> class LossyPaddedVersion(version.LooseVersion):
... '''Subclass version.LooseVersion to compare things like
... "10.6" and "10.6.0" as equal'''
... def __init__(self, s):
... self.parse(s)
...
... def _pad(self, version_list, max_length):
... 'Pad a version list by adding extra 0 components to the end'
... # copy the version_list so we don't modify it
... cmp_list = list(version_list)
... while len(cmp_list) < max_length:
... cmp_list.append(0)
... return cmp_list
...
... def __cmp__(self, other):
... if isinstance(other, str):
... other = MunkiLooseVersion(other)
... max_length = max(len(self.version), len(other.version))
... self_cmp_version = self._pad(self.version, max_length)
... other_cmp_version = self._pad(other.version, max_length)
... return cmp(self_cmp_version, other_cmp_version)
>>> def testver(older, newer):
... o = LossyPaddedVersion(paranoidver(older))
... n = LossyPaddedVersion(paranoidver(newer))
... return o < n
>>> testver('3.4', '3.5')
True
>>> testver('3.4.0', '3.5-rc')
True
>>> testver('3.4-rc', '3.5')
True
>>> testver('3.4-rc+10-deadbeef', '3.5')
True
>>> testver('3.4.2', '3.5-rc')
True
>>> testver('3.4.2', '3.5-rc+10-deadbeef')
True
>>> testver('4.2+483-5d44d7d4076e', '4.2.1+598-48d1e1214d8c')
True
>>> testver('4.3-rc', '4.3')
True
>>> testver('4.3', '4.3-rc')
False
"""
major, minor, micro, extra = util.versiontuple(ver, n=4)
if micro is None:
micro = 0
if extra:
if extra.startswith('rc'):
if minor == 0:
major -= 1
minor = 9
else:
minor -= 1
micro = 9999
extra = '-' + extra
else:
extra = '+' + extra
else:
extra = ''
return '%d.%d.%d%s' % (major, minor, micro, extra)
def main(argv):
opts = ap.parse_args(argv[1:])
if opts.selftest:
import doctest
doctest.testmod()
return
with open(opts.versionfile) as f:
for l in f:
if l.startswith('version = b'):
# version number is entire line minus the quotes
ver = l[len('version = b') + 1 : -2]
break
if opts.paranoid:
print(paranoidver(ver))
else:
print(ver)
if __name__ == '__main__':
main(sys.argv)