Fix additional refolding-encoding edge case.

In this case, the higher level syntactic unit fit on the remainder of
the line in un-encoded format, so the encoding check never happened.  To
fix this, we look inside the current unit to see if has anything that
was originally encoded.

Author: bitdancer

Lib/email/_header_value_parser.py

@@ -162,6 +162,14 @@ def comments(self):
             comments.extend(token.comments)
         return comments
 
+    def has_token_type(self, *token_types):
+        if self.token_type in token_types:
+            return True
+        for t in self:
+            if t.has_token_type(*token_types):
+                return True
+        return False
+
     def fold(self, *, policy):
         return _refold_parse_tree(self, policy=policy)
 
@@ -922,6 +930,9 @@ def pop_trailing_ws(self):
     def comments(self):
         return []
 
+    def has_token_type(self, *token_types):
+        return self.token_type in token_types
+
     def __getnewargs__(self):
         return(str(self), self.token_type)
 
@@ -2813,7 +2824,7 @@ def _refold_parse_tree(parse_tree, *, policy):
             continue
         tstr = str(part)
         if not want_encoding:
-            if part.token_type in ('ptext', 'vtext'):
+            if part.token_type == 'ptext' or part.has_token_type('vtext'):
                 # Encode if tstr contains special characters.
                 want_encoding = not SPECIALSNL.isdisjoint(tstr)
             else:

Lib/test/test_email/test__header_value_parser.py

@@ -3096,6 +3096,11 @@ def test_address_list_with_specials_in_encoded_word(self):
              'A =?utf-8?q?v=C3=A9ry?= long name\n'
              ' containing =?utf-8?q?a=2C?= comma\n'
              ' <[email protected]>\n'),
+            ('=?utf-8?Q?a=2C=20123456789012345678901234567890123456?='
+                ' <[email protected]>',
+             '=?utf-8?q?a=2C?=\n'
+             ' 123456789012345678901234567890123456\n'
+             ' <[email protected]>\n'),
         ]
         for (to, folded) in cases:
             with self.subTest(to=to):