File bsc1188607-pythreadstate_clear-decref.patch of Package python3.32815

From 35ab1e55aa0a359762c9eb6b2b5f7490440d6b1c Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Tue, 24 Mar 2020 17:12:19 +0100
Subject: [PATCH] bpo-20526: Fix PyThreadState_Clear(): don't decref frame
 (GH-19120) (GH-19136)

PyThreadState.frame is a borrowed reference, not a strong reference:
PyThreadState_Clear() must not call Py_CLEAR(tstate->frame).

Remove test_threading.test_warnings_at_exit(): we cannot warranty
that the Python thread state of daemon threads is cleared in a
reliable way during Python shutdown.

(cherry picked from commit 5804f878e779712e803be927ca8a6df389d82cdf)
(cherry picked from commit e97c8b0688bc62959ced477d842fcd37992ef649)
---
 Include/pystate.h |    1 +
 Python/pystate.c  |   12 ++++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2020-03-23-18-08-34.bpo-20526.NHNZIv.rst

--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -88,6 +88,7 @@ typedef struct _ts {
     struct _ts *next;
     PyInterpreterState *interp;
 
+    /* Borrowed reference to the current frame (it can be NULL) */
     struct _frame *frame;
     int recursion_depth;
     char overflowed; /* The stack has overflowed. Allow 50 more calls
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -409,11 +409,19 @@ _PyState_ClearModules(void)
 void
 PyThreadState_Clear(PyThreadState *tstate)
 {
-    if (Py_VerboseFlag && tstate->frame != NULL)
+    if (Py_VerboseFlag && tstate->frame != NULL) {
+        /* bpo-20526: After the main thread calls
+           _PyRuntimeState_SetFinalizing() in Py_FinalizeEx(), threads must
+           exit when trying to take the GIL. If a thread exit in the middle of
+           _PyEval_EvalFrameDefault(), tstate->frame is not reset to its
+           previous value. It is more likely with daemon threads, but it can
+           happen with regular threads if threading._shutdown() fails
+           (ex: interrupted by CTRL+C). */
         fprintf(stderr,
           "PyThreadState_Clear: warning: thread still has a frame\n");
+    }
 
-    Py_CLEAR(tstate->frame);
+    /* Don't clear tstate->frame: it is a borrowed reference */
 
     Py_CLEAR(tstate->dict);
     Py_CLEAR(tstate->async_exc);