bpo-37482: Fix email address name with encoded words and special chars (GH-14561)

Special characters in email address header display names are normally
put within double quotes. However, encoded words (=?charset?x?...?=) are
not allowed withing double quotes. When the header contains a word with
special characters and another word that must be encoded, the first one
must also be encoded.

In the next example, the display name in the From header is quoted and
therefore the comma is allowed; in the To header, the comma is not
within quotes and not encoded, which is not allowed and therefore
rejected by some mail servers.

From: "Foo Bar, France" <foo@example.com>
To: Foo Bar, =?utf-8?q?Espa=C3=B1a?= <foo@example.com>





https://bugs.python.org/issue37482

1 files changed, 24 insertions, 0 deletions

diff --git a/Lib/test/test_email/test_headerregistry.py b/Lib/test/test_email/test_headerregistry.py
index 4758f4b1c52..38f7ddbf06d 100644
--- a/Lib/test/test_email/test_headerregistry.py
+++ b/Lib/test/test_email/test_headerregistry.py
@@ -1547,6 +1547,30 @@ class TestAddressAndGroup(TestEmailBase):
 
 class TestFolding(TestHeaderBase):
 
+    def test_address_display_names(self):
+        """Test the folding and encoding of address headers."""
+        for name, result in (
+                ('Foo Bar, France', '"Foo Bar, France"'),
+                ('Foo Bar (France)', '"Foo Bar (France)"'),
+                ('Foo Bar, España', 'Foo =?utf-8?q?Bar=2C_Espa=C3=B1a?='),
+                ('Foo Bar (España)', 'Foo Bar =?utf-8?b?KEVzcGHDsWEp?='),
+                ('Foo, Bar España', '=?utf-8?q?Foo=2C_Bar_Espa=C3=B1a?='),
+                ('Foo, Bar [España]', '=?utf-8?q?Foo=2C_Bar_=5BEspa=C3=B1a=5D?='),
+                ('Foo Bär, France', 'Foo =?utf-8?q?B=C3=A4r=2C?= France'),
+                ('Foo Bär <France>', 'Foo =?utf-8?q?B=C3=A4r_=3CFrance=3E?='),
+                (
+                    'Lôrem ipsum dôlôr sit amet, cônsectetuer adipiscing. '
+                    'Suspendisse pôtenti. Aliquam nibh. Suspendisse pôtenti.',
+                    '=?utf-8?q?L=C3=B4rem_ipsum_d=C3=B4l=C3=B4r_sit_amet=2C_c'
+                    '=C3=B4nsectetuer?=\n =?utf-8?q?adipiscing=2E_Suspendisse'
+                    '_p=C3=B4tenti=2E_Aliquam_nibh=2E?=\n Suspendisse =?utf-8'
+                    '?q?p=C3=B4tenti=2E?=',
+                    ),
+                ):
+            h = self.make_header('To', Address(name, addr_spec='a@b.com'))
+            self.assertEqual(h.fold(policy=policy.default),
+                                    'To: %s <a@b.com>\n' % result)
+
     def test_short_unstructured(self):
         h = self.make_header('subject', 'this is a test')
         self.assertEqual(h.fold(policy=policy.default),