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.
# extension to emulate invoking 'dirstate.write()' at the time
# specified by '[fakedirstatewritetime] fakenow', only when
# 'dirstate.write()' is invoked via functions below:
#
# - 'workingctx._poststatusfixup()' (= 'repo.status()')
# - 'committablectx.markcommitted()'
from mercurial import (
context,
dirstatemap as dirstatemapmod,
extensions,
policy,
registrar,
)
from mercurial.dirstateutils import timestamp
from mercurial.utils import dateutil
try:
from mercurial import rustext
rustext.__name__ # force actual import (see hgdemandimport)
except ImportError:
rustext = None
configtable = {}
configitem = registrar.configitem(configtable)
configitem(
b'fakedirstatewritetime',
b'fakenow',
default=None,
)
parsers = policy.importmod('parsers')
has_rust_dirstate = policy.importrust('dirstate') is not None
def pack_dirstate(orig, dmap, copymap, pl):
return orig(dmap, copymap, pl)
def fakewrite(ui, func):
# fake "now" of 'pack_dirstate' only if it is invoked while 'func'
fakenow = ui.config(b'fakedirstatewritetime', b'fakenow')
if not fakenow:
# Execute original one, if fakenow isn't configured. This is
# useful to prevent subrepos from executing replaced one,
# because replacing 'parsers.pack_dirstate' is also effective
# in subrepos.
return func()
# parsing 'fakenow' in YYYYmmddHHMM format makes comparison between
# 'fakenow' value and 'touch -t YYYYmmddHHMM' argument easy
fakenow = dateutil.parsedate(fakenow, [b'%Y%m%d%H%M'])[0]
fakenow = timestamp.timestamp((fakenow, 0, False))
if has_rust_dirstate:
# The Rust implementation does not use public parse/pack dirstate
# to prevent conversion round-trips
orig_dirstatemap_write = dirstatemapmod.dirstatemap.write
wrapper = lambda self, tr, st: orig_dirstatemap_write(self, tr, st)
dirstatemapmod.dirstatemap.write = wrapper
orig_get_fs_now = timestamp.get_fs_now
wrapper = lambda *args: pack_dirstate(orig_pack_dirstate, *args)
orig_module = parsers
orig_pack_dirstate = parsers.pack_dirstate
orig_module.pack_dirstate = wrapper
timestamp.get_fs_now = (
lambda *args: fakenow
) # XXX useless for this purpose now
try:
return func()
finally:
orig_module.pack_dirstate = orig_pack_dirstate
timestamp.get_fs_now = orig_get_fs_now
if has_rust_dirstate:
dirstatemapmod.dirstatemap.write = orig_dirstatemap_write
def _poststatusfixup(orig, workingctx, status, fixup):
ui = workingctx.repo().ui
return fakewrite(ui, lambda: orig(workingctx, status, fixup))
def markcommitted(orig, committablectx, node):
ui = committablectx.repo().ui
return fakewrite(ui, lambda: orig(committablectx, node))
def extsetup(ui):
extensions.wrapfunction(
context.workingctx, '_poststatusfixup', _poststatusfixup
)
extensions.wrapfunction(context.workingctx, 'markcommitted', markcommitted)