gh-124703: Change back to raising bdb.BdbQuit when exiting pdb in 'inline' mode in a REPL session

Lib/pdb.py

@@ -1758,7 +1758,10 @@ def do_quit(self, arg):
 
         Quit from the debugger. The program being executed is aborted.
         """
-        if self.mode == 'inline':
+        # Show prompt to kill process when in 'inline' mode and if pdb was not
+        # started from an interactive console. The attribute sys.ps1 is only
+        # defined if the interpreter is in interactive mode.
+        if self.mode == 'inline' and not hasattr(sys, 'ps1'):
             while True:
                 try:
                     reply = input('Quitting pdb will kill the process. Quit anyway? [y/n] ')

Lib/test/test_pdb.py

@@ -19,6 +19,8 @@
 from test.support import force_not_colorized, os_helper
 from test.support.import_helper import import_module
 from test.support.pty_helper import run_pty, FakeInput
+from test.support.script_helper import kill_python
+# Deferred import: from test.test_repl import spawn_repl
 from unittest.mock import patch
 
 SKIP_CORO_TESTS = False
@@ -4278,6 +4280,8 @@ def test_checkline_is_not_executable(self):
                 self.assertFalse(db.checkline(os_helper.TESTFN, lineno))
 
 
+QUIT_PROMPT_QUESTION = "Quit anyway"
+
 @support.requires_subprocess()
 class PdbTestInline(unittest.TestCase):
     @unittest.skipIf(sys.flags.safe_path,
@@ -4331,15 +4335,38 @@ def test_quit(self):
 
         stdout, stderr = self._run_script(script, commands)
         self.assertIn("2", stdout)
-        self.assertIn("Quit anyway", stdout)
+        self.assertIn(QUIT_PROMPT_QUESTION, stdout)
         # Closing stdin will quit the debugger anyway so we need to confirm
         # it's the quit command that does the job
         # call/return event will print --Call-- and --Return--
         self.assertNotIn("--", stdout)
         # Normal exit should not print anything to stderr
         self.assertEqual(stderr, "")
         # The quit prompt should be printed exactly twice
-        self.assertEqual(stdout.count("Quit anyway"), 2)
+        self.assertEqual(stdout.count(QUIT_PROMPT_QUESTION), 2)
+
+
+@support.force_not_colorized_test_class
+@support.requires_subprocess()
+class TestREPLSession(unittest.TestCase):
+    def test_return_from_inline_mode_to_REPL(self):
+        # GH-124703: Raise BdbQuit when exiting pdb in REPL session.
+        # This allows the REPL session to continue.
+        user_input = """
+            x = 'Spam'
+            import pdb
+            pdb.set_trace(commands=['x * 3', 'q'])
+            x[::-1] * 3
+        """
+        from test.test_repl import spawn_repl
+        p = spawn_repl()
+        p.stdin.write(textwrap.dedent(user_input))
+        output = kill_python(p)
+        self.assertIn('SpamSpamSpam', output)
+        self.assertNotIn(QUIT_PROMPT_QUESTION, output)
+        self.assertIn('BdbQuit', output)
+        self.assertIn('mapSmapSmapS', output)
+        self.assertEqual(p.returncode, 0)
 
 
 @support.requires_subprocess()

Misc/NEWS.d/next/Library/2025-02-21-09-05-44.gh-issue-124703.AMJD4Y.rst

@@ -0,0 +1 @@
+Executing ``quit`` command in :mod:`pdb` will raise :exc:`bdb.BdbQuit` when :mod:`pdb` is started from an interactive console using :func:`breakpoint` or :func:`pdb.set_trace`.