[gdb/python] Make sure python sys.exit makes gdb exit

With gdb 15.1, python sys.exit no longer makes gdb exit:
...
$ gdb -q -batch -ex "python sys.exit(2)" -ex "print 123"; echo $?
Python Exception <class 'SystemExit'>: 2
Error occurred in Python: 2
$1 = 123
0
...

This is a change in behaviour since commit a207f6b3a38 ("Rewrite "python"
command exception handling"), first available in gdb 15.1.

This patch reverts to the old behaviour by handling PyExc_SystemExit in
gdbpy_handle_exception, such what we have instead:
...
$ gdb -q -batch -ex "python sys.exit(2)" -ex "print 123"; echo $?
2
...

Tested on x86_64-linux, with python 3.6 and 3.13.

Tested-By: Guinevere Larsen <blarsen@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>

PR python/31946
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31946

1 files changed, 29 insertions, 0 deletions

diff --git a/gdb/python/py-utils.c b/gdb/python/py-utils.c
index 8064cec..0bc18a6 100644
--- a/gdb/python/py-utils.c
+++ b/gdb/python/py-utils.c
@@ -390,6 +390,35 @@ gdbpy_handle_exception ()
 
   if (fetched_error.type_matches (PyExc_KeyboardInterrupt))
     throw_quit ("Quit");
+  else if (fetched_error.type_matches (PyExc_SystemExit))
+    {
+      gdbpy_ref<> value = fetched_error.value ();
+      gdbpy_ref<> code (PyObject_GetAttrString (value.get (), "code"));
+      int exit_arg;
+
+      if (code.get () == Py_None)
+	{
+	  /* CODE == None: exit status is 0.  */
+	  exit_arg = 0;
+	}
+      else if (code.get () != nullptr && PyLong_Check (code.get ()))
+	{
+	  /* CODE == integer: exit status is aforementioned integer.  */
+	  exit_arg = PyLong_AsLong (code.get ());
+	}
+      else
+	{
+	  if (code.get () == nullptr)
+	    gdbpy_print_stack ();
+
+	  /* Otherwise: exit status is 1, print code to stderr.  */
+	  if (msg != nullptr)
+	    gdb_printf (gdb_stderr, "%s\n", msg.get ());
+	  exit_arg = 1;
+	}
+
+      quit_force (&exit_arg, 0);
+    }
   else if (! fetched_error.type_matches (gdbpy_gdberror_exc)
 	   || msg == NULL || *msg == '\0')
     {