gh-149309: Use BaseException as BdbQuit's base class (#149337)

Author: gaogaotiantian

Doc/library/bdb.rst

@@ -17,6 +17,10 @@ The following exception is defined:
 
    Exception raised by the :class:`Bdb` class for quitting the debugger.
 
+   .. versionchanged:: 3.16
+      :exc:`BdbQuit` now inherits from :exc:`BaseException` instead of
+      :exc:`Exception`.
+
 
 The :mod:`!bdb` module also defines two classes:
 

Doc/whatsnew/3.16.rst

@@ -119,6 +119,15 @@ asyncio
   (Contributed by Sam Bull in :gh:`94984`.)
 
 
+bdb
+---
+
+* :exc:`bdb.BdbQuit` is now a subclass of :exc:`BaseException`, instead of
+  :exc:`Exception`, to allow it to be used for cleanly exiting the debugger without
+  being accidentally caught by user code.
+  (Contributed by Tian Gao in :gh:`149337`.)
+
+
 bz2
 ---
 

Lib/bdb.py

@@ -13,7 +13,7 @@
 GENERATOR_AND_COROUTINE_FLAGS = CO_GENERATOR | CO_COROUTINE | CO_ASYNC_GENERATOR
 
 
-class BdbQuit(Exception):
+class BdbQuit(BaseException):
     """Exception to give up completely."""
 
 

Lib/test/test_bdb.py

@@ -1248,6 +1248,15 @@ def test_format_stack_entry_no_lineno(self):
         self.assertIn('Warning: lineno is None',
                       Bdb().format_stack_entry((sys._getframe(), None)))
 
+    def test_bdb_quit_base_exception(self):
+        # gh-149309
+        try:
+            raise _bdb.BdbQuit()
+        except Exception:
+            self.fail(f'BdbQuit should not be caught by Exception')
+        except BaseException:
+            pass
+
 
 if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Library/2026-05-03-22-52-07.gh-issue-149309.gXhk9Y.rst

@@ -0,0 +1 @@
+:exc:`bdb.BdbQuit` is now a subclass of :exc:`BaseException`, instead of :exc:`Exception`, to allow it to be used for cleanly exiting the debugger without being accidentally caught by user code.