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.
# split.py - split a changeset into smaller ones
#
# Copyright 2015 Laurent Charignon <lcharignon@fb.com>
# Copyright 2017 Facebook, Inc.
#
# 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 split a changeset into smaller ones (EXPERIMENTAL)"""
from mercurial.i18n import _
from mercurial.node import (
nullrev,
short,
)
from mercurial import (
bookmarks,
cmdutil,
commands,
error,
hg,
logcmdutil,
pycompat,
registrar,
revsetlang,
rewriteutil,
scmutil,
util,
)
# allow people to use split without explicitly enabling rebase extension
from . import rebase
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'split',
[
(b'r', b'rev', b'', _(b"revision to split"), _(b'REV')),
(b'', b'rebase', True, _(b'rebase descendants after split')),
]
+ cmdutil.commitopts2,
_(b'hg split [--no-rebase] [[-r] REV]'),
helpcategory=command.CATEGORY_CHANGE_MANAGEMENT,
helpbasic=True,
)
def split(ui, repo, *revs, **opts):
"""split a changeset into smaller ones
Repeatedly prompt changes and commit message for new changesets until there
is nothing left in the original changeset.
If --rev was not given, split the working directory parent.
By default, rebase connected non-obsoleted descendants onto the new
changeset. Use --no-rebase to avoid the rebase.
"""
opts = pycompat.byteskwargs(opts)
revlist = []
if opts.get(b'rev'):
revlist.append(opts.get(b'rev'))
revlist.extend(revs)
with repo.wlock(), repo.lock():
tr = repo.transaction(b'split')
# If the rebase somehow runs into conflicts, make sure
# we close the transaction so the user can continue it.
with util.acceptintervention(tr):
revs = logcmdutil.revrange(repo, revlist or [b'.'])
if len(revs) > 1:
raise error.InputError(_(b'cannot split multiple revisions'))
rev = revs.first()
# Handle nullrev specially here (instead of leaving for precheck()
# below) so we get a nicer message and error code.
if rev is None or rev == nullrev:
ui.status(_(b'nothing to split\n'))
return 1
ctx = repo[rev]
if ctx.node() is None:
raise error.InputError(_(b'cannot split working directory'))
if opts.get(b'rebase'):
# Skip obsoleted descendants and their descendants so the rebase
# won't cause conflicts for sure.
descendants = list(repo.revs(b'(%d::) - (%d)', rev, rev))
torebase = list(
repo.revs(
b'%ld - (%ld & obsolete())::', descendants, descendants
)
)
else:
torebase = []
rewriteutil.precheck(repo, [rev] + torebase, b'split')
if len(ctx.parents()) > 1:
raise error.InputError(_(b'cannot split a merge changeset'))
cmdutil.bailifchanged(repo)
# Deactivate bookmark temporarily so it won't get moved
# unintentionally
bname = repo._activebookmark
if bname and repo._bookmarks[bname] != ctx.node():
bookmarks.deactivate(repo)
wnode = repo[b'.'].node()
top = None
try:
top = dosplit(ui, repo, tr, ctx, opts)
finally:
# top is None: split failed, need update --clean recovery.
# wnode == ctx.node(): wnode split, no need to update.
if top is None or wnode != ctx.node():
hg.clean(repo, wnode, show_stats=False)
if bname:
bookmarks.activate(repo, bname)
if torebase and top:
dorebase(ui, repo, torebase, top)
def dosplit(ui, repo, tr, ctx, opts):
committed = [] # [ctx]
# Set working parent to ctx.p1(), and keep working copy as ctx's content
if ctx.node() != repo.dirstate.p1():
hg.clean(repo, ctx.node(), show_stats=False)
with repo.dirstate.parentchange():
scmutil.movedirstate(repo, ctx.p1())
# Any modified, added, removed, deleted result means split is incomplete
def incomplete(repo):
st = repo.status()
return any((st.modified, st.added, st.removed, st.deleted))
# Main split loop
while incomplete(repo):
if committed:
header = _(
b'HG: Splitting %s. So far it has been split into:\n'
) % short(ctx.node())
# We don't want color codes in the commit message template, so
# disable the label() template function while we render it.
with ui.configoverride(
{(b'templatealias', b'label(l,x)'): b"x"}, b'split'
):
for c in committed:
summary = cmdutil.format_changeset_summary(ui, c, b'split')
header += _(b'HG: - %s\n') % summary
header += _(
b'HG: Write commit message for the next split changeset.\n'
)
else:
header = _(
b'HG: Splitting %s. Write commit message for the '
b'first split changeset.\n'
) % short(ctx.node())
opts.update(
{
b'edit': True,
b'interactive': True,
b'message': header + ctx.description(),
}
)
origctx = repo[b'.']
commands.commit(ui, repo, **pycompat.strkwargs(opts))
newctx = repo[b'.']
# Ensure user didn't do a "no-op" split (such as deselecting
# everything).
if origctx.node() != newctx.node():
committed.append(newctx)
if not committed:
raise error.InputError(_(b'cannot split an empty revision'))
if len(committed) != 1 or committed[0].node() != ctx.node():
# Ensure we don't strip a node if we produce the same commit as already
# exists
scmutil.cleanupnodes(
repo,
{ctx.node(): [c.node() for c in committed]},
operation=b'split',
fixphase=True,
)
return committed[-1]
def dorebase(ui, repo, src, destctx):
rebase.rebase(
ui,
repo,
rev=[revsetlang.formatspec(b'%ld', src)],
dest=revsetlang.formatspec(b'%d', destctx.rev()),
)