bpo-35423: Stop using the "pending calls" machinery for signals. (gh-10972)

This change separates the signal handling trigger in the eval loop from the "pending calls" machinery. There is no semantic change and the difference in performance is insignificant.

The change makes both components less confusing. It also eliminates the risk of changes to the pending calls affecting signal handling. This is particularly relevant for some upcoming pending calls changes I have in the works.

1 files changed, 6 insertions, 0 deletions

diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index 4f8f71a..9d49cbd 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -202,12 +202,15 @@ It raises KeyboardInterrupt.");
 static int
 report_wakeup_write_error(void *data)
 {
+    PyObject *exc, *val, *tb;
     int save_errno = errno;
     errno = (int) (intptr_t) data;
+    PyErr_Fetch(&exc, &val, &tb);
     PyErr_SetFromErrno(PyExc_OSError);
     PySys_WriteStderr("Exception ignored when trying to write to the "
                       "signal wakeup fd:\n");
     PyErr_WriteUnraisable(NULL);
+    PyErr_Restore(exc, val, tb);
     errno = save_errno;
     return 0;
 }
@@ -216,6 +219,8 @@ report_wakeup_write_error(void *data)
 static int
 report_wakeup_send_error(void* data)
 {
+    PyObject *exc, *val, *tb;
+    PyErr_Fetch(&exc, &val, &tb);
     /* PyErr_SetExcFromWindowsErr() invokes FormatMessage() which
        recognizes the error codes used by both GetLastError() and
        WSAGetLastError */
@@ -223,6 +228,7 @@ report_wakeup_send_error(void* data)
     PySys_WriteStderr("Exception ignored when trying to send to the "
                       "signal wakeup fd:\n");
     PyErr_WriteUnraisable(NULL);
+    PyErr_Restore(exc, val, tb);
     return 0;
 }
 #endif   /* MS_WINDOWS */