procutil: try and avoid angering CoreFoundation on macOS
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.
Differential Revision: https://phab.mercurial-scm.org/D7615
--- a/mercurial/utils/procutil.py Wed Dec 11 17:35:29 2019 +0100
+++ b/mercurial/utils/procutil.py Thu Dec 05 16:19:16 2019 -0500
@@ -423,7 +423,10 @@
return rc
-def gui():
+_is_gui = None
+
+
+def _gui():
'''Are we running in a GUI?'''
if pycompat.isdarwin:
if b'SSH_CONNECTION' in encoding.environ:
@@ -439,6 +442,13 @@
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():
"""Return the command used to execute current hg
@@ -583,6 +593,11 @@
`Subprocess.wait` function for the spawned process. This is mostly
useful for developers that need to make sure the spawned process
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
# based on http://code.activestate.com/recipes/278731
if record_wait is None: