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.
# Mercurial extension to provide the 'hg children' command
#
# Copyright 2007 by Intevation GmbH <intevation@intevation.de>
#
# Author(s):
# Thomas Arendsen Hein <thomas@intevation.de>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''command to display child changesets (DEPRECATED)
This extension is deprecated. You should use :hg:`log -r
"children(REV)"` instead.
'''
from mercurial.i18n import _
from mercurial import (
cmdutil,
logcmdutil,
pycompat,
registrar,
)
templateopts = cmdutil.templateopts
cmdtable = {}
command = registrar.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b'ships-with-hg-core'
@command(
b'children',
[
(
b'r',
b'rev',
b'.',
_(b'show children of the specified revision'),
_(b'REV'),
),
]
+ templateopts,
_(b'hg children [-r REV] [FILE]'),
helpcategory=command.CATEGORY_CHANGE_NAVIGATION,
inferrepo=True,
)
def children(ui, repo, file_=None, **opts):
"""show the children of the given or working directory revision
Print the children of the working directory's revisions. If a
revision is given via -r/--rev, the children of that revision will
be printed. If a file argument is given, revision in which the
file was last changed (after the working directory revision or the
argument to --rev if given) is printed.
Please use :hg:`log` instead::
hg children => hg log -r "children(.)"
hg children -r REV => hg log -r "children(REV)"
See :hg:`help log` and :hg:`help revsets.children`.
"""
opts = pycompat.byteskwargs(opts)
rev = opts.get(b'rev')
ctx = logcmdutil.revsingle(repo, rev)
if file_:
fctx = repo.filectx(file_, changeid=ctx.rev())
childctxs = [fcctx.changectx() for fcctx in fctx.children()]
else:
childctxs = ctx.children()
displayer = logcmdutil.changesetdisplayer(ui, repo, opts)
for cctx in childctxs:
displayer.show(cctx)
displayer.close()