modify

Author: bkjoh

Lib/getpass.py

@@ -145,7 +145,12 @@ def fallback_getpass(prompt='Password: ', stream=None, *, echo_char=None):
 
 def _check_echo_char(echo_char):
     # Single-character ASCII excluding control characters
-    if echo_char and not (
+    if echo_char is None:
+        return
+    if not isinstance(echo_char, str):
+        raise TypeError("'echo_char' must be type 'str' or 'None', got: "
+                        f"{echo_char!r} (type: {type(echo_char).__name__})")
+    if not (
         len(echo_char) == 1
         and echo_char.isprintable()
         and echo_char.isascii()

Lib/test/test_getpass.py

@@ -200,6 +200,38 @@ def test_control_chars_with_echo_char(self):
         self.assertEqual(result, expect_result)
         self.assertEqual('Password: *******\x08 \x08', mock_output.getvalue())
 
+class GetpassEchoCharValidationTest(unittest.TestCase):
+    def test_accepts_none(self):
+        getpass._check_echo_char(None)
+
+    def test_accepts_single_printable_ascii(self):
+        for ch in ["*", "A", " "]:
+            getpass._check_echo_char(ch)
+
+    def test_rejects_multi_character_strings(self):
+        for s in ["***", "AA", "aA*!"]:
+            with self.assertRaises(ValueError):
+                getpass._check_echo_char(s)
+
+    def test_rejects_non_ascii(self):
+        for s in ["Æ", "❤️", "🐍"]:
+            with self.assertRaises(ValueError):
+                getpass._check_echo_char(s)
+
+    def test_rejects_control_characters(self):
+        for ch in ["\n", "\t", "\r", "\x00", "\x7f", "\x07"]:
+            with self.assertRaises(ValueError):
+                getpass._check_echo_char(ch)
+
+    def test_rejects_non_string(self):
+        for item in [b"*", 0]:
+            with self.assertRaises(TypeError):
+                getpass._check_echo_char(item)
+
+    def test_rejects_empty_string(self):
+        for item in [""]:
+            with self.assertRaises(ValueError):
+                getpass._check_echo_char(item)
 
 if __name__ == "__main__":
     unittest.main()