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.
# This test verifies the conformance of various classes to various
# storage interfaces.
import silenttestrunner
from mercurial import (
error,
filelog,
revlog,
transaction,
ui as uimod,
vfs as vfsmod,
)
from mercurial.testing import storage as storagetesting
try:
from hgext import sqlitestore
except ImportError:
sqlitestore = None
try:
import sqlite3
if sqlite3.sqlite_version_info < (3, 8, 3):
# WITH clause not supported
sqlitestore = None
except ImportError:
pass
try:
from mercurial import zstd
zstd.__version__
except ImportError:
zstd = None
STATE = {
'lastindex': 0,
'ui': uimod.ui(),
'vfs': vfsmod.vfs(b'.', realpath=True),
}
def makefilefn(self):
"""Factory for filelog instances."""
fl = filelog.filelog(STATE['vfs'], b'filelog-%d' % STATE['lastindex'])
STATE['lastindex'] += 1
return fl
def maketransaction(self):
vfsmap = {b'plain': STATE['vfs'], b'store': STATE['vfs']}
return transaction.transaction(
STATE['ui'].warn, STATE['vfs'], vfsmap, b'journal', b'undo'
)
def addrawrevision(
self,
fl,
tr,
node,
p1,
p2,
linkrev,
rawtext=None,
delta=None,
censored=False,
ellipsis=False,
extstored=False,
):
flags = 0
if censored:
flags |= revlog.REVIDX_ISCENSORED
if ellipsis:
flags |= revlog.REVIDX_ELLIPSIS
if extstored:
flags |= revlog.REVIDX_EXTSTORED
if rawtext is not None:
fl._revlog.addrawrevision(rawtext, tr, linkrev, p1, p2, node, flags)
elif delta is not None:
fl._revlog.addrawrevision(
rawtext, tr, linkrev, p1, p2, node, flags, cachedelta=delta
)
else:
raise error.Abort('must supply rawtext or delta arguments')
# We may insert bad data. Clear caches to prevent e.g. cache hits to
# bypass hash verification.
fl._revlog.clearcaches()
# Assigning module-level attributes that inherit from unittest.TestCase
# is all that is needed to register tests.
filelogindextests = storagetesting.makeifileindextests(
makefilefn, maketransaction, addrawrevision
)
filelogdatatests = storagetesting.makeifiledatatests(
makefilefn, maketransaction, addrawrevision
)
filelogmutationtests = storagetesting.makeifilemutationtests(
makefilefn, maketransaction, addrawrevision
)
def makesqlitefile(self):
path = STATE['vfs'].join(b'db-%d.db' % STATE['lastindex'])
STATE['lastindex'] += 1
db = sqlitestore.makedb(path)
compression = b'zstd' if zstd else b'zlib'
return sqlitestore.sqlitefilestore(db, b'dummy-path', compression)
def addrawrevisionsqlite(
self,
fl,
tr,
node,
p1,
p2,
linkrev,
rawtext=None,
delta=None,
censored=False,
ellipsis=False,
extstored=False,
):
flags = 0
if censored:
flags |= sqlitestore.FLAG_CENSORED
if ellipsis | extstored:
raise error.Abort(
b'support for ellipsis and extstored flags not ' b'supported'
)
if rawtext is not None:
fl._addrawrevision(node, rawtext, tr, linkrev, p1, p2, flags=flags)
elif delta is not None:
fl._addrawrevision(
node, rawtext, tr, linkrev, p1, p2, storedelta=delta, flags=flags
)
else:
raise error.Abort(b'must supply rawtext or delta arguments')
if sqlitestore is not None:
sqlitefileindextests = storagetesting.makeifileindextests(
makesqlitefile, maketransaction, addrawrevisionsqlite
)
sqlitefiledatatests = storagetesting.makeifiledatatests(
makesqlitefile, maketransaction, addrawrevisionsqlite
)
sqlitefilemutationtests = storagetesting.makeifilemutationtests(
makesqlitefile, maketransaction, addrawrevisionsqlite
)
if __name__ == '__main__':
silenttestrunner.main(__name__)