[3.8] bpo-32498: Improve exception message on passing bytes to urllib.parse.unquote

Lib/test/test_urllib.py

@@ -1245,6 +1245,12 @@ def test_unquote_with_unicode(self):
         self.assertEqual(expect, result,
                          "using unquote(): %r != %r" % (expect, result))
 
+    def test_unquoting_with_bytes_input(self):
+        # Bytes not supported yet
+        with self.assertRaisesRegex(TypeError, 'Expected str, got bytes'):
+            given = b'bl\xc3\xa5b\xc3\xa6rsyltet\xc3\xb8y'
+            urllib.parse.unquote(given)
+
 class urlencode_Tests(unittest.TestCase):
     """Tests for urlencode()"""
 

Lib/urllib/parse.py

@@ -631,6 +631,8 @@ def unquote(string, encoding='utf-8', errors='replace'):
 
     unquote('abc%20def') -> 'abc def'.
     """
+    if isinstance(string, bytes):
+        raise TypeError('Expected str, got bytes')
     if '%' not in string:
         string.split
         return string

Misc/NEWS.d/next/Library/2020-10-18-19-22-39.bpo-32498.MoqSgo.rst

@@ -0,0 +1,3 @@
+Clearer exception message when passing an argument of type bytes to
+:func:`urllib.parse.unquote`.  This is only for 3.8; in 3.9 and later this
+function accepts bytes inputs as well.  PR by Irit Katriel.