[Updated] D9660: worker: restrict use of worker procesess to the main thread

[joerg.sonnenberger (Joerg Sonnenberger)]

joerg.sonnenberger updated this revision to Diff 24628.

REPOSITORY
  rHG Mercurial

CHANGES SINCE LAST UPDATE
  https://phab.mercurial-scm.org/D9660?vs=24514&id=24628

BRANCH
  default

CHANGES SINCE LAST ACTION
  https://phab.mercurial-scm.org/D9660/new/

REVISION DETAIL
  https://phab.mercurial-scm.org/D9660

AFFECTED FILES
  mercurial/worker.py

CHANGE DETAILS

diff --git a/mercurial/worker.py b/mercurial/worker.py
--- a/mercurial/worker.py
+++ b/mercurial/worker.py
@@ -67,6 +67,9 @@
 
 if pycompat.ispy3:
 
+    def ismainthread():
+        return threading.current_thread() == threading.main_thread()
+
     class _blockingreader(object):
         def __init__(self, wrapped):
             self._wrapped = wrapped
@@ -100,6 +103,9 @@
 
 else:
 
+    def ismainthread():
+        return isinstance(threading.current_thread(), threading._MainThread)
+
     def _blockingreader(wrapped):
         return wrapped
 
@@ -155,6 +161,11 @@
     release the GIL.
     """
     enabled = ui.configbool(b'worker', b'enabled')
+    if enabled and _platformworker is _posixworker and not ismainthread():
+        # The POSIX worker has to install a handler for SIGCHLD.
+        # Python up to 3.9 only allows this in the main thread.
+        enabled = False
+
     if enabled and worthwhile(ui, costperarg, len(args), threadsafe=threadsafe):
         return _platformworker(ui, func, staticargs, args, hasretval)
     return func(*staticargs + (args,))



To: joerg.sonnenberger, #hg-reviewers, marmoute
Cc: marmoute, mercurial-patches
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