fix: disable IEXTEN in non-canonical mode to allow Ctrl+V (LNEXT) handling

Author: CuriousLearner

Lib/getpass.py

@@ -111,6 +111,7 @@ def unix_getpass(prompt='Password: ', stream=None, *, echo_char=None):
                 term_ctrl_chars = None
                 if echo_char:
                     new[3] &= ~termios.ICANON
+                    new[3] &= ~termios.IEXTEN
                     term_ctrl_chars = _get_terminal_ctrl_chars(fd)
                 tcsetattr_flags = termios.TCSAFLUSH
                 if hasattr(termios, 'TCSASOFT'):

Lib/test/test_getpass.py

@@ -216,11 +216,11 @@ def test_kill_ctrl_u_with_echo_char(self):
         result = getpass._raw_input('Password: ', mock_output, mock_input,
                                     '*')
         self.assertEqual(result, expect_result)
-        # Should show "***" then clear all 3, then show "***" for "bar"
+        # Should show "***" then refresh to clear, then show "***" for "bar"
         output = mock_output.getvalue()
         self.assertIn('***', output)
-        # Should have backspaces to clear the "foo" part
-        self.assertIn('\b', output)
+        # Display refresh uses \r to rewrite the line including prompt
+        self.assertIn('\r', output)
 
     def test_werase_ctrl_w_with_echo_char(self):
         # Ctrl+W (WERASE) should delete the previous word