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 os
import tempfile
from mercurial import (
pycompat,
util,
)
from hgext.fastannotate import error, revmap
def genhsh(i):
return pycompat.bytechr(i) + b'\0' * 19
def gettemppath():
fd, path = tempfile.mkstemp()
os.close(fd)
os.unlink(path)
return path
def ensure(condition):
if not condition:
raise RuntimeError('Unexpected')
def testbasicreadwrite():
path = gettemppath()
rm = revmap.revmap(path)
ensure(rm.maxrev == 0)
for i in range(5):
ensure(rm.rev2hsh(i) is None)
ensure(rm.hsh2rev(b'\0' * 20) is None)
paths = [
b'',
b'a',
None,
b'b',
b'b',
b'c',
b'c',
None,
b'a',
b'b',
b'a',
b'a',
]
for i in range(1, 5):
ensure(rm.append(genhsh(i), sidebranch=(i & 1), path=paths[i]) == i)
ensure(rm.maxrev == 4)
for i in range(1, 5):
ensure(rm.hsh2rev(genhsh(i)) == i)
ensure(rm.rev2hsh(i) == genhsh(i))
# re-load and verify
rm.flush()
rm = revmap.revmap(path)
ensure(rm.maxrev == 4)
for i in range(1, 5):
ensure(rm.hsh2rev(genhsh(i)) == i)
ensure(rm.rev2hsh(i) == genhsh(i))
ensure(bool(rm.rev2flag(i) & revmap.sidebranchflag) == bool(i & 1))
# append without calling save() explicitly
for i in range(5, 12):
ensure(
rm.append(genhsh(i), sidebranch=(i & 1), path=paths[i], flush=True)
== i
)
# re-load and verify
rm = revmap.revmap(path)
ensure(rm.maxrev == 11)
for i in range(1, 12):
ensure(rm.hsh2rev(genhsh(i)) == i)
ensure(rm.rev2hsh(i) == genhsh(i))
ensure(rm.rev2path(i) == paths[i] or paths[i - 1])
ensure(bool(rm.rev2flag(i) & revmap.sidebranchflag) == bool(i & 1))
os.unlink(path)
# missing keys
ensure(rm.rev2hsh(12) is None)
ensure(rm.rev2hsh(0) is None)
ensure(rm.rev2hsh(-1) is None)
ensure(rm.rev2flag(12) is None)
ensure(rm.rev2path(12) is None)
ensure(rm.hsh2rev(b'\1' * 20) is None)
# illformed hash (not 20 bytes)
try:
rm.append(b'\0')
ensure(False)
except Exception:
pass
def testcorruptformat():
path = gettemppath()
# incorrect header
with open(path, 'wb') as f:
f.write(b'NOT A VALID HEADER')
try:
revmap.revmap(path)
ensure(False)
except error.CorruptedFileError:
pass
# rewrite the file
os.unlink(path)
rm = revmap.revmap(path)
rm.append(genhsh(0), flush=True)
rm = revmap.revmap(path)
ensure(rm.maxrev == 1)
# corrupt the file by appending a byte
size = os.stat(path).st_size
with open(path, 'ab') as f:
f.write(b'\xff')
try:
revmap.revmap(path)
ensure(False)
except error.CorruptedFileError:
pass
# corrupt the file by removing the last byte
ensure(size > 0)
with open(path, 'wb') as f:
f.truncate(size - 1)
try:
revmap.revmap(path)
ensure(False)
except error.CorruptedFileError:
pass
os.unlink(path)
def testcopyfrom():
path = gettemppath()
rm = revmap.revmap(path)
for i in range(1, 10):
ensure(
rm.append(genhsh(i), sidebranch=(i & 1), path=(b'%d' % (i // 3)))
== i
)
rm.flush()
# copy rm to rm2
rm2 = revmap.revmap()
rm2.copyfrom(rm)
path2 = gettemppath()
rm2.path = path2
rm2.flush()
# two files should be the same
ensure(len({util.readfile(p) for p in [path, path2]}) == 1)
os.unlink(path)
os.unlink(path2)
class fakefctx:
def __init__(self, node, path=None):
self._node = node
self._path = path
def node(self):
return self._node
def path(self):
return self._path
def testcontains():
path = gettemppath()
rm = revmap.revmap(path)
for i in range(1, 5):
ensure(rm.append(genhsh(i), sidebranch=(i & 1)) == i)
for i in range(1, 5):
ensure(((genhsh(i), None) in rm) == ((i & 1) == 0))
ensure((fakefctx(genhsh(i)) in rm) == ((i & 1) == 0))
for i in range(5, 10):
ensure(fakefctx(genhsh(i)) not in rm)
ensure((genhsh(i), None) not in rm)
# "contains" checks paths
rm = revmap.revmap()
for i in range(1, 5):
ensure(rm.append(genhsh(i), path=(b'%d' % (i // 2))) == i)
for i in range(1, 5):
ensure(fakefctx(genhsh(i), path=(b'%d' % (i // 2))) in rm)
ensure(fakefctx(genhsh(i), path=b'a') not in rm)
def testlastnode():
path = gettemppath()
ensure(revmap.getlastnode(path) is None)
rm = revmap.revmap(path)
ensure(revmap.getlastnode(path) is None)
for i in range(1, 10):
hsh = genhsh(i)
rm.append(hsh, path=(b'%d' % (i // 2)), flush=True)
ensure(revmap.getlastnode(path) == hsh)
rm2 = revmap.revmap(path)
ensure(rm2.rev2hsh(rm2.maxrev) == hsh)
testbasicreadwrite()
testcorruptformat()
testcopyfrom()
testcontains()
testlastnode()