Prevent folding of non-ascii message-id headers.

Also, remove empty lines from classes that don't have any methods.
python · warsaw · Jun 4, 2019 · May 17, 2019 · May 18, 2019 · May 27, 2019
commit aca404a87094ea8b5452960b432aee91c9f46769
diff --git a/Doc/library/email.headerregistry.rst b/Doc/library/email.headerregistry.rst
@@ -321,19 +321,26 @@ variant, :attr:`~.BaseHeader.max_count` is set to 1.
 
     The default mappings are:
 
-      :subject:         UniqueUnstructuredHeader
-      :date:            UniqueDateHeader
-      :resent-date:     DateHeader
-      :orig-date:       UniqueDateHeader
-      :sender:          UniqueSingleAddressHeader
-      :resent-sender:   SingleAddressHeader
-      :to:              UniqueAddressHeader
-      :resent-to:       AddressHeader
-      :cc:              UniqueAddressHeader
-      :resent-cc:       AddressHeader
-      :from:            UniqueAddressHeader
-      :resent-from:     AddressHeader
-      :reply-to:        UniqueAddressHeader
+      :subject:                   UniqueUnstructuredHeader
+      :date:                      UniqueDateHeader
+      :resent-date:               DateHeader
+      :orig-date:                 UniqueDateHeader
+      :sender:                    UniqueSingleAddressHeader
+      :resent-sender:             SingleAddressHeader
+      :to:                        UniqueAddressHeader
+      :resent-to:                 AddressHeader
+      :cc:                        UniqueAddressHeader
+      :resent-cc:                 AddressHeader
+      :bcc:                       UniqueAddressHeader
+      :resent-bcc:                AddressHeader
+      :from:                      UniqueAddressHeader
+      :resent-from:               AddressHeader
+      :reply-to:                  UniqueAddressHeader
+      :mime-version:              MIMEVersionHeader
+      :content-type:              ContentTypeHeader
+      :content-disposition:       ContentDispositionHeader
+      :content-transfer-encoding: ContentTransferEncodingHeader
+      :message-id:                MessageIDHeader
 
     ``HeaderRegistry`` has the following methods:
 

diff --git a/Lib/email/_header_value_parser.py b/Lib/email/_header_value_parser.py
@@ -179,37 +179,30 @@ def comments(self):
 
 
 class UnstructuredTokenList(TokenList):
-
     token_type = 'unstructured'
 
 
 class Phrase(TokenList):
-
     token_type = 'phrase'
 
 class Word(TokenList):
-
     token_type = 'word'
 
 
 class CFWSList(WhiteSpaceTokenList):
-
     token_type = 'cfws'
 
 
 class Atom(TokenList):
-
     token_type = 'atom'
 
 
 class Token(TokenList):
-
     token_type = 'token'
     encode_as_ew = False
 
 
 class EncodedWord(TokenList):
-
     token_type = 'encoded-word'
     cte = None
     charset = None
@@ -496,18 +489,15 @@ def domain(self):
 
 
 class DotAtom(TokenList):
-
     token_type = 'dot-atom'
 
 
 class DotAtomText(TokenList):
-
     token_type = 'dot-atom-text'
     as_ew_allowed = True
 
 
 class NoFoldLiteral(TokenList):
-
     token_type = 'no-fold-literal'
     as_ew_allowed = False
 
@@ -815,46 +805,40 @@ def params(self):
 
 
 class ContentType(ParameterizedHeaderValue):
-
     token_type = 'content-type'
     as_ew_allowed = False
     maintype = 'text'
     subtype = 'plain'
 
 
 class ContentDisposition(ParameterizedHeaderValue):
-
     token_type = 'content-disposition'
     as_ew_allowed = False
     content_disposition = None
 
 
 class ContentTransferEncoding(TokenList):
-
     token_type = 'content-transfer-encoding'
     as_ew_allowed = False
     cte = '7bit'
 
 
 class HeaderLabel(TokenList):
-
     token_type = 'header-label'
     as_ew_allowed = False
 
 
 class MsgID(TokenList):
-
     token_type = 'msg-id'
     as_ew_allowed = False
+    fold_subparts = False
 
 
 class MessageID(MsgID):
-
     token_type = 'message-id'
 
 
 class Header(TokenList):
-
     token_type = 'header'
 
 
@@ -2763,6 +2747,10 @@ def _refold_parse_tree(parse_tree, *, policy):
                 # to unpacking the subparts and wrapping them.
             if not hasattr(part, 'encode'):
                 # It's not a Terminal, do each piece individually.
+                if not getattr(part, 'fold_subparts', True):
+                    # This part can't be folded and also doesn't allow folding
+                    # of subparts.
+                    wrap_as_ew_blocked += 1
                 parts = list(part) + parts
             else:
                 # It's a terminal, wrap it as an encoded word, possibly

diff --git a/Lib/test/test_email/test_headerregistry.py b/Lib/test/test_email/test_headerregistry.py
@@ -1656,5 +1656,26 @@ def test_message_id_header_is_not_folded(self):
             h.fold(policy=policy.default.clone(max_line_length=20)),
             'Message-ID: <[email protected]>\n')
 
+        # Test message-id isn't folded when id-right is no-fold-literal.
+        h = self.make_header(
+            'Message-ID',
+            '<somemessageidlongerthan@[127.0.0.0.0.0.0.0.0.1]>')
+        self.assertEqual(
+            h.fold(policy=policy.default.clone(max_line_length=20)),
+            'Message-ID: <somemessageidlongerthan@[127.0.0.0.0.0.0.0.0.1]>\n')
+
+        # Test message-id isn't folded when id-right is non-ascii characters.
+        h = self.make_header('Message-ID', '<ईमेल@wők.com>')
+        self.assertEqual(
+            h.fold(policy=policy.default.clone(max_line_length=30)),
+            'Message-ID: <ईमेल@wők.com>\n')
+
+        # Test message-id is folded without breaking the msg-id token into
+        # encoded words, *even* if they don't fit into max_line_length.
+        h = self.make_header('Message-ID', '<ईमेलfromMessage@wők.com>')
+        self.assertEqual(
+            h.fold(policy=policy.default.clone(max_line_length=20)),
+            'Message-ID:\n <ईमेलfromMessage@wők.com>\n')
+
 if __name__ == '__main__':
     unittest.main()