procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
#!/usr/bin/env python2
import argparse
import os
import subprocess
import sys
try:
# 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))
except subprocess.CalledProcessError:
# We're probably running with a PyOxidized Mercurial, so just
# proceed and hope it works out okay.
pass
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)