bpo-36333, bpo-36356: Fix _PyEval_FiniThreads() (GH-12432)

_PyEval_FiniThreads() now free the pending lock.

Author: vstinner

Python/ceval.c

@@ -169,8 +169,10 @@ PyEval_ThreadsInitialized(void)
 void
 PyEval_InitThreads(void)
 {
- if (gil_created())
+ if (gil_created()) {
  return;
+ }
+
  PyThread_init_thread();
  create_gil();
  take_gil(_PyThreadState_GET());
@@ -184,10 +186,17 @@ PyEval_InitThreads(void)
 void
 _PyEval_FiniThreads(void)
 {
- if (!gil_created())
+ if (!gil_created()) {
  return;
+ }
+
  destroy_gil();
  assert(!gil_created());
+
+ if (_PyRuntime.ceval.pending.lock != NULL) {
+ PyThread_free_lock(_PyRuntime.ceval.pending.lock);
+ _PyRuntime.ceval.pending.lock = NULL;
+ }
 }
 
 void