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.
import unittest
from mercurial import policy
PartialDiscovery = policy.importrust('discovery', member='PartialDiscovery')
try:
from mercurial.cext import parsers as cparsers
except ImportError:
cparsers = None
# picked from test-parse-index2, copied rather than imported
# so that it stays stable even if test-parse-index2 changes or disappears.
data_non_inlined = (
b'\x00\x00\x00\x01\x00\x00\x00\x00\x00\x01D\x19'
b'\x00\x07e\x12\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\xff\xff'
b'\xff\xff\xff\xff\xd1\xf4\xbb\xb0\xbe\xfc\x13\xbd\x8c\xd3\x9d'
b'\x0f\xcd\xd9;\x8c\x07\x8cJ/\x00\x00\x00\x00\x00\x00\x00\x00\x00'
b'\x00\x00\x00\x00\x00\x00\x01D\x19\x00\x00\x00\x00\x00\xdf\x00'
b'\x00\x01q\x00\x00\x00\x01\x00\x00\x00\x01\x00\x00\x00\x00\xff'
b'\xff\xff\xff\xc1\x12\xb9\x04\x96\xa4Z1t\x91\xdfsJ\x90\xf0\x9bh'
b'\x07l&\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
b'\x00\x01D\xf8\x00\x00\x00\x00\x01\x1b\x00\x00\x01\xb8\x00\x00'
b'\x00\x01\x00\x00\x00\x02\x00\x00\x00\x01\xff\xff\xff\xff\x02\n'
b'\x0e\xc6&\xa1\x92\xae6\x0b\x02i\xfe-\xe5\xbao\x05\xd1\xe7\x00'
b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01F'
b'\x13\x00\x00\x00\x00\x01\xec\x00\x00\x03\x06\x00\x00\x00\x01'
b'\x00\x00\x00\x03\x00\x00\x00\x02\xff\xff\xff\xff\x12\xcb\xeby1'
b'\xb6\r\x98B\xcb\x07\xbd`\x8f\x92\xd9\xc4\x84\xbdK\x00\x00\x00'
b'\x00\x00\x00\x00\x00\x00\x00\x00\x00'
)
class fakechangelog:
def __init__(self, idx):
self.index = idx
class fakerepo:
def __init__(self, idx):
"""Just make so that self.changelog.index is the given idx."""
self.changelog = fakechangelog(idx)
@unittest.skipIf(
PartialDiscovery is None or cparsers is None,
"rustext or the C Extension parsers module "
"discovery relies on is not available",
)
class rustdiscoverytest(unittest.TestCase):
"""Test the correctness of binding to Rust code.
This test is merely for the binding to Rust itself: extraction of
Python variable, giving back the results etc.
It is not meant to test the algorithmic correctness of the provided
methods. Hence the very simple embedded index data is good enough.
Algorithmic correctness is asserted by the Rust unit tests.
"""
def parseindex(self):
return cparsers.parse_index2(data_non_inlined, False)[0]
def repo(self):
return fakerepo(self.parseindex())
def testindex(self):
idx = self.parseindex()
# checking our assumptions about the index binary data:
self.assertEqual(
{i: (r[5], r[6]) for i, r in enumerate(idx)},
{0: (-1, -1), 1: (0, -1), 2: (1, -1), 3: (2, -1)},
)
def testaddcommonsmissings(self):
disco = PartialDiscovery(self.repo(), [3], True)
self.assertFalse(disco.hasinfo())
self.assertFalse(disco.iscomplete())
disco.addcommons([1])
self.assertTrue(disco.hasinfo())
self.assertFalse(disco.iscomplete())
disco.addmissings([2])
self.assertTrue(disco.hasinfo())
self.assertTrue(disco.iscomplete())
self.assertEqual(disco.commonheads(), {1})
def testaddmissingsstats(self):
disco = PartialDiscovery(self.repo(), [3], True)
self.assertIsNone(disco.stats()['undecided'], None)
disco.addmissings([2])
self.assertEqual(disco.stats()['undecided'], 2)
def testaddinfocommonfirst(self):
disco = PartialDiscovery(self.repo(), [3], True)
disco.addinfo([(1, True), (2, False)])
self.assertTrue(disco.hasinfo())
self.assertTrue(disco.iscomplete())
self.assertEqual(disco.commonheads(), {1})
def testaddinfomissingfirst(self):
disco = PartialDiscovery(self.repo(), [3], True)
disco.addinfo([(2, False), (1, True)])
self.assertTrue(disco.hasinfo())
self.assertTrue(disco.iscomplete())
self.assertEqual(disco.commonheads(), {1})
def testinitnorandom(self):
PartialDiscovery(self.repo(), [3], True, randomize=False)
if __name__ == '__main__':
import silenttestrunner
silenttestrunner.main(__name__)