bpo-16500: Use register_at_fork() in the threading module (#1843)
* bpo-16500: Use register_at_fork() in the threading module
* Update comment at top of _after_fork()
diff --git a/Lib/threading.py b/Lib/threading.py
index 0b59464..2eaf49a 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -1,5 +1,6 @@
"""Thread module emulating a subset of Java's threading model."""
+import os as _os
import sys as _sys
import _thread
@@ -943,6 +944,7 @@
exc_tb.tb_frame.f_code.co_name)), file=self._stderr)
exc_tb = exc_tb.tb_next
print(("%s: %s" % (exc_type, exc_value)), file=self._stderr)
+ self._stderr.flush()
# Make sure that exc_tb gets deleted since it is a memory
# hog; deleting everything else is just for thoroughness
finally:
@@ -1319,10 +1321,9 @@
def _after_fork():
- # This function is called by Python/ceval.c:PyEval_ReInitThreads which
- # is called from PyOS_AfterFork_Child. Here we cleanup threading module
- # state that should not exist after a fork.
-
+ """
+ Cleanup threading module state that should not exist after a fork.
+ """
# Reset _active_limbo_lock, in case we forked while the lock was held
# by another (non-forked) thread. http://bugs.python.org/issue874900
global _active_limbo_lock, _main_thread
@@ -1356,3 +1357,7 @@
_active.clear()
_active.update(new_active)
assert len(_active) == 1
+
+
+if hasattr(_os, "fork"):
+ _os.register_at_fork(_after_fork, when="child")
diff --git a/Python/ceval.c b/Python/ceval.c
index b114b5b..6140815 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -240,8 +240,6 @@
void
PyEval_ReInitThreads(void)
{
- _Py_IDENTIFIER(_after_fork);
- PyObject *threading, *result;
PyThreadState *current_tstate = PyThreadState_GET();
if (!gil_created())
@@ -251,22 +249,6 @@
take_gil(current_tstate);
main_thread = PyThread_get_thread_ident();
- /* Update the threading module with the new state.
- */
- threading = PyMapping_GetItemString(current_tstate->interp->modules,
- "threading");
- if (threading == NULL) {
- /* threading not imported */
- PyErr_Clear();
- return;
- }
- result = _PyObject_CallMethodId(threading, &PyId__after_fork, NULL);
- if (result == NULL)
- PyErr_WriteUnraisable(threading);
- else
- Py_DECREF(result);
- Py_DECREF(threading);
-
/* Destroy all threads except the current one */
_PyThreadState_DeleteExcept(current_tstate);
}