Don't run garbage collection on interpreter exit if it was explicitly disabled

by the user.

Include/objimpl.h

@@ -224,11 +224,12 @@ PyAPI_FUNC(void) PyObject_SetArenaAllocator(PyObjectArenaAllocator *allocator);
  * ==========================
  */
 
-/* C equivalent of gc.collect(). */
+/* C equivalent of gc.collect() which ignores the state of gc.enabled. */
 PyAPI_FUNC(Py_ssize_t) PyGC_Collect(void);
 
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(Py_ssize_t) _PyGC_CollectNoFail(void);
+PyAPI_FUNC(Py_ssize_t) _PyGC_CollectIfEnabled(void);
 #endif
 
 /* Test if a type has a GC head */

Modules/gcmodule.c

@@ -1596,6 +1596,15 @@ PyGC_Collect(void)
     return n;
 }
 
+Py_ssize_t
+_PyGC_CollectIfEnabled(void)
+{
+    if (!enabled)
+        return 0;
+
+    return PyGC_Collect();
+}
+
 Py_ssize_t
 _PyGC_CollectNoFail(void)
 {

Python/pylifecycle.c

@@ -600,12 +600,12 @@ Py_FinalizeEx(void)
      * XXX but I'm unclear on exactly how that one happens.  In any case,
      * XXX I haven't seen a real-life report of either of these.
      */
-    PyGC_Collect();
+    _PyGC_CollectIfEnabled();
 #ifdef COUNT_ALLOCS
     /* With COUNT_ALLOCS, it helps to run GC multiple times:
        each collection might release some types from the type
        list, so they become garbage. */
-    while (PyGC_Collect() > 0)
+    while (_PyGC_CollectIfEnabled() > 0)
         /* nothing */;
 #endif
     /* Destroy all modules */
@@ -632,7 +632,7 @@ Py_FinalizeEx(void)
      * XXX Python code getting called.
      */
 #if 0
-    PyGC_Collect();
+    _PyGC_CollectIfEnabled();
 #endif
 
     /* Disable tracemalloc after all Python objects have been destroyed,