gh-104341: Minor Fixes in the _thread Module

Include/internal/pycore_interp.h

@@ -57,8 +57,6 @@ struct _is {
         uint64_t next_unique_id;
         /* The linked list of threads, newest first. */
         PyThreadState *head;
-        /* Used in Modules/_threadmodule.c. */
-        long count;
         /* Support for runtime thread stack size tuning.
            A value of 0 means using the platform's default stack size
            or the size specified by the THREAD_STACK_SIZE macro. */

Lib/test/test_threading.py

@@ -345,7 +345,7 @@ def run(self):
 
     def test_limbo_cleanup(self):
         # Issue 7481: Failure to start thread should cleanup the limbo map.
-        def fail_new_thread(*args):
+        def fail_new_thread(*args, **kwargs):
             raise threading.ThreadError()
         _start_new_thread = threading._start_new_thread
         threading._start_new_thread = fail_new_thread

Lib/threading.py

@@ -49,6 +49,10 @@
 except AttributeError:
     _CRLock = None
 TIMEOUT_MAX = _thread.TIMEOUT_MAX
+try:
+    _internal_after_fork = _thread._after_fork
+except AttributeError:
+    _internal_after_fork = None
 del _thread
 
 
@@ -968,7 +972,7 @@ def start(self):
         with _active_limbo_lock:
             _limbo[self] = self
         try:
-            _start_new_thread(self._bootstrap, ())
+            _start_new_thread(self._bootstrap, (), daemonic=self._daemonic)
         except Exception:
             with _active_limbo_lock:
                 del _limbo[self]
@@ -1677,4 +1681,6 @@ def _after_fork():
 
 
 if hasattr(_os, "register_at_fork"):
+    if _internal_after_fork is not None:
+        _os.register_at_fork(after_in_child=_internal_after_fork)
     _os.register_at_fork(after_in_child=_after_fork)