May 4, 2025 · May 4, 2025 · May 4, 2025 · May 4, 2025 · May 4, 2025
diff --git a/Lib/cmd.py b/Lib/cmd.py
            endidx = readline.get_endidx() - stripped
            if begidx>0:
                cmd, args, foo = self.parseline(line)
                ifcmd == '':
                ifnot cmd:
                    compfunc = self.completedefault
                else:
                    try:
diff --git a/Lib/test/test_cmd.py b/Lib/test/test_cmd.py
        self.assertIn(b'ab_completion_test', output)
        self.assertIn(b'tab completion success', output)

    def test_bang_completion_without_do_shell(self):
        script = textwrap.dedent("""
            import cmd
            class simplecmd(cmd.Cmd):
                def completedefault(self, text, line, begidx, endidx):
                    return ["hello"]

                def default(self, line):
                    if line.replace(" ", "") == "!hello":
                        print('tab completion success')
                    else:
                        print('tab completion failure')
                    return True

            simplecmd().cmdloop()
        """)

        # '! h' or '!h' and complete 'ello' to 'hello'
        for input in [b"! h\t\n", b"!h\t\n"]:
            with self.subTest(input=input):
                output = run_pty(script, input)
                self.assertIn(b'hello', output)
                self.assertIn(b'tab completion success', output)

 def load_tests(loader, tests, pattern):
    tests.addTest(doctest.DocTestSuite())
    return tests
diff --git a/Misc/NEWS.d/next/Library/2025-05-03-21-55-33.gh-issue-133363.PTLnRP.rst b/Misc/NEWS.d/next/Library/2025-05-03-21-55-33.gh-issue-133363.PTLnRP.rst
 The :class:`cmd.Cmd` class has been fixed to reliably call the ``completedefault``
 method whenever the ``do_shell`` method is not defined and tab completion is
 requested for a line beginning with ``!``.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -273,7 +273,7 @@ def complete(self, text, state):
		endidx = readline.get_endidx() - stripped
		if begidx>0:
		cmd, args, foo = self.parseline(line)
		ifcmd == '':
		ifnot cmd:
		compfunc = self.completedefault
		else:
		try:
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -289,6 +289,30 @@ def do_tab_completion_test(self, args):
		self.assertIn(b'ab_completion_test', output)
		self.assertIn(b'tab completion success', output)

		def test_bang_completion_without_do_shell(self):
		script = textwrap.dedent("""
		import cmd
		class simplecmd(cmd.Cmd):
		def completedefault(self, text, line, begidx, endidx):
		return ["hello"]

		def default(self, line):
		if line.replace(" ", "") == "!hello":
		print('tab completion success')
		else:
		print('tab completion failure')
		return True

		simplecmd().cmdloop()
		""")

		# '! h' or '!h' and complete 'ello' to 'hello'
		for input in [b"! h\t\n", b"!h\t\n"]:
		with self.subTest(input=input):
		output = run_pty(script, input)
		self.assertIn(b'hello', output)
		self.assertIn(b'tab completion success', output)

		def load_tests(loader, tests, pattern):
		tests.addTest(doctest.DocTestSuite())
		return tests
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		The :class:`cmd.Cmd` class has been fixed to reliably call the ``completedefault``
		method whenever the ``do_shell`` method is not defined and tab completion is
		requested for a line beginning with ``!``.