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.
#!/usr/bin/env python3
import getopt
import sys
import hgdemandimport
hgdemandimport.enable()
from mercurial.i18n import _
from mercurial import (
context,
error,
fancyopts,
simplemerge,
ui as uimod,
util,
)
from mercurial.utils import procutil, stringutil
options = [
(b'L', b'label', [], _(b'labels to use on conflict markers')),
(b'a', b'text', None, _(b'treat all files as text')),
(b'p', b'print', None, _(b'print results instead of overwriting LOCAL')),
(b'', b'no-minimal', None, _(b'no effect (DEPRECATED)')),
(b'h', b'help', None, _(b'display help and exit')),
(b'q', b'quiet', None, _(b'suppress output')),
]
usage = _(
b'''simplemerge [OPTS] LOCAL BASE OTHER
Simple three-way file merge utility with a minimal feature set.
Apply to LOCAL the changes necessary to go from BASE to OTHER.
By default, LOCAL is overwritten with the results of this operation.
'''
)
class ParseError(Exception):
"""Exception raised on errors in parsing the command line."""
def showhelp():
procutil.stdout.write(usage)
procutil.stdout.write(b'\noptions:\n')
out_opts = []
for shortopt, longopt, default, desc in options:
out_opts.append(
(
b'%2s%s'
% (
shortopt and b'-%s' % shortopt,
longopt and b' --%s' % longopt,
),
b'%s' % desc,
)
)
opts_len = max([len(opt[0]) for opt in out_opts])
for first, second in out_opts:
procutil.stdout.write(b' %-*s %s\n' % (opts_len, first, second))
def _verifytext(input, ui, quiet=False, allow_binary=False):
"""verifies that text is non-binary (unless opts[text] is passed,
then we just warn)"""
if stringutil.binary(input.text()):
msg = _(b"%s looks like a binary file.") % input.fctx.path()
if not quiet:
ui.warn(_(b'warning: %s\n') % msg)
if not allow_binary:
sys.exit(1)
try:
for fp in (sys.stdin, procutil.stdout, sys.stderr):
procutil.setbinary(fp)
opts = {}
try:
bargv = [a.encode('utf8') for a in sys.argv[1:]]
args = fancyopts.fancyopts(bargv, options, opts)
except getopt.GetoptError as e:
raise ParseError(e)
if opts[b'help']:
showhelp()
sys.exit(0)
if len(args) != 3:
raise ParseError(_(b'wrong number of arguments').decode('utf8'))
mode = b'merge'
if len(opts[b'label']) > 2:
mode = b'merge3'
local, base, other = args
overrides = opts[b'label']
if len(overrides) > 3:
raise error.InputError(b'can only specify three labels.')
labels = [local, other, base]
labels[: len(overrides)] = overrides
local_input = simplemerge.MergeInput(
context.arbitraryfilectx(local), labels[0]
)
other_input = simplemerge.MergeInput(
context.arbitraryfilectx(other), labels[1]
)
base_input = simplemerge.MergeInput(
context.arbitraryfilectx(base), labels[2]
)
quiet = opts.get(b'quiet')
allow_binary = opts.get(b'text')
ui = uimod.ui.load()
_verifytext(local_input, ui, quiet=quiet, allow_binary=allow_binary)
_verifytext(base_input, ui, quiet=quiet, allow_binary=allow_binary)
_verifytext(other_input, ui, quiet=quiet, allow_binary=allow_binary)
merged_text, conflicts = simplemerge.simplemerge(
local_input,
base_input,
other_input,
mode,
allow_binary=allow_binary,
)
if opts.get(b'print'):
ui.fout.write(merged_text)
else:
util.writefile(local, merged_text)
sys.exit(1 if conflicts else 0)
except ParseError as e:
e = stringutil.forcebytestr(e)
procutil.stdout.write(b"%s: %s\n" % (sys.argv[0].encode('utf8'), e))
showhelp()
sys.exit(1)
except error.Abort as e:
procutil.stderr.write(b"abort: %s\n" % e)
sys.exit(255)
except KeyboardInterrupt:
sys.exit(255)