This is an archive of the discontinued Mercurial Phabricator instance.

Differential D7615

procutil: try and avoid angering CoreFoundation on macOS
ClosedPublic

Authored by durin42 on Dec 12 2019, 12:38 PM.

Details

Reviewers
pulkit
Group Reviewers
hg-reviewers
Commits
rHGa89381e04c58: procutil: try and avoid angering CoreFoundation on macOS
Summary

We've seen failures like this:

objc[57662]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called.
objc[57662]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.

I think this is due to forking off some background processes during
hg update or similar. I don't have any conclusive proof this is the
fork() call that's to blame, but it's the most likely one since the
regular hg update codepath uses the other fork() invocation (via
workers) and we don't get this report from non-Google macOS users.

Ugh.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

durin42 created this revision.Dec 12 2019, 12:38 PM
durin42 updated this revision to Diff 18755.Dec 16 2019, 9:27 AM
pulkit accepted this revision.Dec 17 2019, 6:58 AM
This revision is now accepted and ready to land.Dec 17 2019, 6:58 AM
durin42 added a commit: rHGa89381e04c58: procutil: try and avoid angering CoreFoundation on macOS.Dec 17 2019, 7:56 AM
Closed by commit rHGa89381e04c58: procutil: try and avoid angering CoreFoundation on macOS (authored by durin42). · Explain Why
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/utils/procutil.py (17 lines)

Diff 18807

mercurial/utils/procutil.py

out.write(line) out.write(line)
proc.wait() proc.wait()
rc = proc.returncode rc = proc.returncode
if pycompat.sysplatform == b'OpenVMS' and rc & 1: if pycompat.sysplatform == b'OpenVMS' and rc & 1:
rc = 0 rc = 0
return rc return rc
def gui(): _is_gui = None
def _gui():
'''Are we running in a GUI?''' '''Are we running in a GUI?'''
if pycompat.isdarwin: if pycompat.isdarwin:
if b'SSH_CONNECTION' in encoding.environ: if b'SSH_CONNECTION' in encoding.environ:
# handle SSH access to a box where the user is logged in # handle SSH access to a box where the user is logged in
return False return False
elif getattr(osutil, 'isgui', None): elif getattr(osutil, 'isgui', None):
# check if a CoreGraphics session is available # check if a CoreGraphics session is available
return osutil.isgui() return osutil.isgui()
else: else:
# pure build; use a safe default # pure build; use a safe default
return True return True
else: else:
return pycompat.iswindows or encoding.environ.get(b"DISPLAY") return pycompat.iswindows or encoding.environ.get(b"DISPLAY")
def gui():
global _is_gui
if _is_gui is None:
_is_gui = _gui()
return _is_gui
def hgcmd(): def hgcmd():
"""Return the command used to execute current hg """Return the command used to execute current hg
This is different from hgexecutable() because on Windows we want This is different from hgexecutable() because on Windows we want
to avoid things opening new shell windows like batch files, so we to avoid things opening new shell windows like batch files, so we
get either the python call or current executable. get either the python call or current executable.
""" """
if resourceutil.mainfrozen(): if resourceutil.mainfrozen():
'''Spawn a command without waiting for it to finish. '''Spawn a command without waiting for it to finish.
When `record_wait` is not None, the spawned process will not be fully When `record_wait` is not None, the spawned process will not be fully
detached and the `record_wait` argument will be called with a the detached and the `record_wait` argument will be called with a the
`Subprocess.wait` function for the spawned process. This is mostly `Subprocess.wait` function for the spawned process. This is mostly
useful for developers that need to make sure the spawned process useful for developers that need to make sure the spawned process
finished before a certain point. (eg: writing test)''' finished before a certain point. (eg: writing test)'''
if pycompat.isdarwin:
# avoid crash in CoreFoundation in case another thread
# calls gui() while we're calling fork().
gui()
# double-fork to completely detach from the parent process # double-fork to completely detach from the parent process
# based on http://code.activestate.com/recipes/278731 # based on http://code.activestate.com/recipes/278731
if record_wait is None: if record_wait is None:
pid = os.fork() pid = os.fork()
if pid: if pid:
if not ensurestart: if not ensurestart:
return return
# Parent process # Parent process