bpo-23395: Fix PyErr_SetInterrupt if the SIGINT signal is ignored or not handled (GH-7778)

``_thread.interrupt_main()`` now avoids setting the Python error status if the ``SIGINT`` signal is ignored or not handled by Python.
(cherry picked from commit 608876b6b1eb59538e6c29671a733033fb8b5be7)

Co-authored-by: Matěj Cepl <mcepl@cepl.eu>

1 files changed, 9 insertions, 4 deletions

diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index e70c6fc396..a0722b731c 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -1562,13 +1562,18 @@ PyErr_CheckSignals(void)
 }
 
 
-/* Replacements for intrcheck.c functionality
- * Declared in pyerrors.h
- */
+/* Simulate the effect of a signal.SIGINT signal arriving. The next time
+   PyErr_CheckSignals is called,  the Python SIGINT signal handler will be
+   raised.
+
+   Missing signal handler for the SIGINT signal is silently ignored. */
 void
 PyErr_SetInterrupt(void)
 {
-    trip_signal(SIGINT);
+    if ((Handlers[SIGINT].func != IgnoreHandler) &&
+        (Handlers[SIGINT].func != DefaultHandler)) {
+        trip_signal(SIGINT);
+    }
 }
 
 void