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.
# automv.py
#
# Copyright 2013-2016 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.
"""check for unrecorded moves at commit time (EXPERIMENTAL)
This extension checks at commit/amend time if any of the committed files
comes from an unrecorded mv.
The threshold at which a file is considered a move can be set with the
``automv.similarity`` config option. This option takes a percentage between 0
(disabled) and 100 (files must be identical), the default is 95.
"""
# Using 95 as a default similarity is based on an analysis of the mercurial
# repositories of the cpython, mozilla-central & mercurial repositories, as
# well as 2 very large facebook repositories. At 95 50% of all potential
# missed moves would be caught, as well as correspond with 87% of all
# explicitly marked moves. Together, 80% of moved files are 95% similar or
# more.
#
# See http://markmail.org/thread/5pxnljesvufvom57 for context.
from mercurial.i18n import _
from mercurial import (
commands,
copies,
error,
extensions,
pycompat,
registrar,
scmutil,
similar,
)
configtable = {}
configitem = registrar.configitem(configtable)
configitem(
b'automv',
b'similarity',
default=95,
)
def extsetup(ui):
entry = extensions.wrapcommand(commands.table, b'commit', mvcheck)
entry[1].append(
(b'', b'no-automv', None, _(b'disable automatic file move detection'))
)
def mvcheck(orig, ui, repo, *pats, **opts):
"""Hook to check for moves at commit time"""
opts = pycompat.byteskwargs(opts)
renames = None
disabled = opts.pop(b'no_automv', False)
if not disabled:
threshold = ui.configint(b'automv', b'similarity')
if not 0 <= threshold <= 100:
raise error.Abort(_(b'automv.similarity must be between 0 and 100'))
if threshold > 0:
match = scmutil.match(repo[None], pats, opts)
added, removed = _interestingfiles(repo, match)
uipathfn = scmutil.getuipathfn(repo, legacyrelativevalue=True)
renames = _findrenames(
repo, uipathfn, added, removed, threshold / 100.0
)
with repo.wlock():
if renames is not None:
scmutil._markchanges(repo, (), (), renames)
return orig(ui, repo, *pats, **pycompat.strkwargs(opts))
def _interestingfiles(repo, matcher):
"""Find what files were added or removed in this commit.
Returns a tuple of two lists: (added, removed). Only files not *already*
marked as moved are included in the added list.
"""
stat = repo.status(match=matcher)
added = stat.added
removed = stat.removed
copy = copies.pathcopies(repo[b'.'], repo[None], matcher)
# remove the copy files for which we already have copy info
added = [f for f in added if f not in copy]
return added, removed
def _findrenames(repo, uipathfn, added, removed, similarity):
"""Find what files in added are really moved files.
Any file named in removed that is at least similarity% similar to a file
in added is seen as a rename.
"""
renames = {}
if similarity > 0:
for src, dst, score in similar.findrenames(
repo, added, removed, similarity
):
if repo.ui.verbose:
repo.ui.status(
_(b'detected move of %s as %s (%d%% similar)\n')
% (uipathfn(src), uipathfn(dst), score * 100)
)
renames[dst] = src
if renames:
repo.ui.status(_(b'detected move of %d files\n') % len(renames))
return renames