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.
# hook.py - hook support for mercurial
#
# Copyright 2007 Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import contextlib
import errno
import os
import sys
from .i18n import _
from .pycompat import getattr
from . import (
demandimport,
encoding,
error,
extensions,
pycompat,
util,
)
from .utils import (
procutil,
resourceutil,
stringutil,
)
def pythonhook(ui, repo, htype, hname, funcname, args, throw):
"""call python hook. hook is callable object, looked up as
name in python module. if callable returns "true", hook
fails, else passes. if hook raises exception, treated as
hook failure. exception propagates if throw is "true".
reason for "true" meaning "hook failed" is so that
unmodified commands (e.g. mercurial.commands.update) can
be run as hooks without wrappers to convert return values."""
if callable(funcname):
obj = funcname
funcname = pycompat.sysbytes(obj.__module__ + "." + obj.__name__)
else:
d = funcname.rfind(b'.')
if d == -1:
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" not in a module')
% (hname, funcname)
)
modname = funcname[:d]
oldpaths = sys.path
if resourceutil.mainfrozen():
# binary installs require sys.path manipulation
modpath, modfile = os.path.split(modname)
if modpath and modfile:
sys.path = sys.path[:] + [modpath]
modname = modfile
with demandimport.deactivated():
try:
obj = __import__(pycompat.sysstr(modname))
except (ImportError, SyntaxError):
e1 = sys.exc_info()
try:
# extensions are loaded with hgext_ prefix
obj = __import__("hgext_%s" % pycompat.sysstr(modname))
except (ImportError, SyntaxError):
e2 = sys.exc_info()
if ui.tracebackflag:
ui.warn(
_(
b'exception from first failed import '
b'attempt:\n'
)
)
ui.traceback(e1)
if ui.tracebackflag:
ui.warn(
_(
b'exception from second failed import '
b'attempt:\n'
)
)
ui.traceback(e2)
if not ui.tracebackflag:
tracebackhint = _(
b'run with --traceback for stack trace'
)
else:
tracebackhint = None
raise error.HookLoadError(
_(b'%s hook is invalid: import of "%s" failed')
% (hname, modname),
hint=tracebackhint,
)
sys.path = oldpaths
try:
for p in funcname.split(b'.')[1:]:
obj = getattr(obj, p)
except AttributeError:
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" is not defined')
% (hname, funcname)
)
if not callable(obj):
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" is not callable')
% (hname, funcname)
)
ui.note(_(b"calling hook %s: %s\n") % (hname, funcname))
starttime = util.timer()
try:
r = obj(ui=ui, repo=repo, hooktype=htype, **pycompat.strkwargs(args))
except Exception as exc:
if isinstance(exc, error.Abort):
ui.warn(_(b'error: %s hook failed: %s\n') % (hname, exc.args[0]))
else:
ui.warn(
_(b'error: %s hook raised an exception: %s\n')
% (hname, stringutil.forcebytestr(exc))
)
if throw:
raise
if not ui.tracebackflag:
ui.warn(_(b'(run with --traceback for stack trace)\n'))
ui.traceback()
return True, True
finally:
duration = util.timer() - starttime
ui.log(
b'pythonhook',
b'pythonhook-%s: %s finished in %0.2f seconds\n',
htype,
funcname,
duration,
)
if r:
if throw:
raise error.HookAbort(_(b'%s hook failed') % hname)
ui.warn(_(b'warning: %s hook failed\n') % hname)
return r, False
def _exthook(ui, repo, htype, name, cmd, args, throw):
starttime = util.timer()
env = {}
# make in-memory changes visible to external process
if repo is not None:
tr = repo.currenttransaction()
repo.dirstate.write(tr)
if tr and tr.writepending():
env[b'HG_PENDING'] = repo.root
env[b'HG_HOOKTYPE'] = htype
env[b'HG_HOOKNAME'] = name
if ui.config(b'hooks', b'%s:run-with-plain' % name) == b'auto':
plain = ui.plain()
else:
plain = ui.configbool(b'hooks', b'%s:run-with-plain' % name)
if plain:
env[b'HGPLAIN'] = b'1'
else:
env[b'HGPLAIN'] = b''
for k, v in args.items():
# transaction changes can accumulate MBs of data, so skip it
# for external hooks
if k == b'changes':
continue
if callable(v):
v = v()
if isinstance(v, (dict, list)):
v = stringutil.pprint(v)
env[b'HG_' + k.upper()] = v
if ui.configbool(b'hooks', b'tonative.%s' % name, False):
oldcmd = cmd
cmd = procutil.shelltonative(cmd, env)
if cmd != oldcmd:
ui.note(_(b'converting hook "%s" to native\n') % name)
ui.note(_(b"running hook %s: %s\n") % (name, cmd))
if repo:
cwd = repo.root
else:
cwd = encoding.getcwd()
r = ui.system(cmd, environ=env, cwd=cwd, blockedtag=b'exthook-%s' % (name,))
duration = util.timer() - starttime
ui.log(
b'exthook',
b'exthook-%s: %s finished in %0.2f seconds\n',
name,
cmd,
duration,
)
if r:
desc = procutil.explainexit(r)
if throw:
raise error.HookAbort(_(b'%s hook %s') % (name, desc))
ui.warn(_(b'warning: %s hook %s\n') % (name, desc))
return r
# represent an untrusted hook command
_fromuntrusted = object()
def _allhooks(ui):
"""return a list of (hook-id, cmd) pairs sorted by priority"""
hooks = _hookitems(ui)
# Be careful in this section, propagating the real commands from untrusted
# sources would create a security vulnerability, make sure anything altered
# in that section uses "_fromuntrusted" as its command.
untrustedhooks = _hookitems(ui, _untrusted=True)
for name, value in untrustedhooks.items():
trustedvalue = hooks.get(name, ((), (), name, _fromuntrusted))
if value != trustedvalue:
(lp, lo, lk, lv) = trustedvalue
hooks[name] = (lp, lo, lk, _fromuntrusted)
# (end of the security sensitive section)
return [(k, v) for p, o, k, v in sorted(hooks.values())]
def _hookitems(ui, _untrusted=False):
"""return all hooks items ready to be sorted"""
hooks = {}
for name, cmd in ui.configitems(b'hooks', untrusted=_untrusted):
if (
name.startswith(b'priority.')
or name.startswith(b'tonative.')
or b':' in name
):
continue
priority = ui.configint(b'hooks', b'priority.%s' % name, 0)
hooks[name] = ((-priority,), (len(hooks),), name, cmd)
return hooks
_redirect = False
def redirect(state):
global _redirect
_redirect = state
def hashook(ui, htype):
"""return True if a hook is configured for 'htype'"""
if not ui.callhooks:
return False
for hname, cmd in _allhooks(ui):
if hname.split(b'.')[0] == htype and cmd:
return True
return False
def hook(ui, repo, htype, throw=False, **args):
if not ui.callhooks:
return False
hooks = []
for hname, cmd in _allhooks(ui):
if hname.split(b'.')[0] == htype and cmd:
hooks.append((hname, cmd))
res = runhooks(ui, repo, htype, hooks, throw=throw, **args)
r = False
for hname, cmd in hooks:
r = res[hname][0] or r
return r
@contextlib.contextmanager
def redirect_stdio():
"""Redirects stdout to stderr, if possible."""
oldstdout = -1
try:
if _redirect:
try:
stdoutno = procutil.stdout.fileno()
stderrno = procutil.stderr.fileno()
# temporarily redirect stdout to stderr, if possible
if stdoutno >= 0 and stderrno >= 0:
procutil.stdout.flush()
oldstdout = os.dup(stdoutno)
os.dup2(stderrno, stdoutno)
except (OSError, AttributeError):
# files seem to be bogus, give up on redirecting (WSGI, etc)
pass
yield
finally:
# The stderr is fully buffered on Windows when connected to a pipe.
# A forcible flush is required to make small stderr data in the
# remote side available to the client immediately.
try:
procutil.stderr.flush()
except IOError as err:
if err.errno not in (errno.EPIPE, errno.EIO, errno.EBADF):
raise error.StdioError(err)
if _redirect and oldstdout >= 0:
try:
procutil.stdout.flush() # write hook output to stderr fd
except IOError as err:
if err.errno not in (errno.EPIPE, errno.EIO, errno.EBADF):
raise error.StdioError(err)
os.dup2(oldstdout, stdoutno)
os.close(oldstdout)
def runhooks(ui, repo, htype, hooks, throw=False, **args):
args = pycompat.byteskwargs(args)
res = {}
with redirect_stdio():
for hname, cmd in hooks:
if cmd is _fromuntrusted:
if throw:
raise error.HookAbort(
_(b'untrusted hook %s not executed') % hname,
hint=_(b"see 'hg help config.trusted'"),
)
ui.warn(_(b'warning: untrusted hook %s not executed\n') % hname)
r = 1
raised = False
elif callable(cmd):
r, raised = pythonhook(ui, repo, htype, hname, cmd, args, throw)
elif cmd.startswith(b'python:'):
if cmd.count(b':') >= 2:
path, cmd = cmd[7:].rsplit(b':', 1)
path = util.expandpath(path)
if repo:
path = os.path.join(repo.root, path)
try:
mod = extensions.loadpath(path, b'hghook.%s' % hname)
except Exception:
ui.write(_(b"loading %s hook failed:\n") % hname)
raise
hookfn = getattr(mod, cmd)
else:
hookfn = cmd[7:].strip()
r, raised = pythonhook(
ui, repo, htype, hname, hookfn, args, throw
)
else:
r = _exthook(ui, repo, htype, hname, cmd, args, throw)
raised = False
res[hname] = r, raised
return res