Fix #8077 for non-quit pdb exits.

IPython/core/debugger.py

@@ -282,11 +282,13 b' class Pdb(OldPdb):'
         while True:
             try:
                 OldPdb.interaction(self, frame, traceback)
+                break
             except KeyboardInterrupt:
                 self.shell.write('\n' + self.shell.get_exception_only())
                 break
-            else:
-                break
+            finally:
+                # Pdb sets readline delimiters, so set them back to our own
+                self.shell.readline.set_completer_delims(self.shell.readline_delims)
 
     def new_do_up(self, arg):
         OldPdb.do_up(self, arg)
@@ -308,10 +310,6 b' class Pdb(OldPdb):'
         if hasattr(self, 'old_all_completions'):
             self.shell.Completer.all_completions=self.old_all_completions
 
-        # Pdb sets readline delimiters, so set them back to our own
-        if self.shell.readline is not None:
-            self.shell.readline.set_completer_delims(self.shell.readline_delims)
-
         return OldPdb.do_quit(self, arg)
 
     do_q = do_quit = decorate_fn_with_doc(new_do_quit, OldPdb.do_quit)