File bpo27321-email-no-replace-header.patch of Package python3.28101
From 72ce82abcf9051b18a05350936de7ecab7306662 Mon Sep 17 00:00:00 2001
From: "Miss Skeleton (bot)" <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 19 Oct 2020 16:11:37 -0700
Subject: [PATCH] bpo-27321 Fix email.generator.py to not replace a
non-existent header. (GH-18074)
This PR replaces GH-1977. The reason for the replacement is two-fold.
The fix itself is different is that if the CTE header doesn't exist in the original message, it is inserted. This is important because the new CTE could be quoted-printable whereas the original is implicit 8bit.
Also the tests are different. The test_nonascii_as_string_without_cte test in GH-1977 doesn't actually test the issue in that it passes without the fix. The test_nonascii_as_string_without_content_type_and_cte test is improved here, and even though it doesn't fail without the fix, it is included for completeness.
Automerge-Triggered-By: @warsaw
(cherry picked from commit bf838227c35212709dc43b3c3c57f8e1655c1d24)
Co-authored-by: Mark Sapiro <mark@msapiro.net>
---
Lib/email/generator.py | 6 +
Lib/test/test_email/test_email.py | 35 ++++++++++
Misc/NEWS.d/next/Library/2020-01-19-18-40-26.bpo-27321.8e6SpM.rst | 2
3 files changed, 42 insertions(+), 1 deletion(-)
create mode 100644 Misc/NEWS.d/next/Library/2020-01-19-18-40-26.bpo-27321.8e6SpM.rst
--- a/Lib/email/generator.py
+++ b/Lib/email/generator.py
@@ -186,7 +186,11 @@ class Generator:
# If we munged the cte, copy the message again and re-fix the CTE.
if munge_cte:
msg = deepcopy(msg)
- msg.replace_header('content-transfer-encoding', munge_cte[0])
+ # Preserve the header order if the CTE header already exists.
+ if msg.get('content-transfer-encoding') is None:
+ msg['Content-Transfer-Encoding'] = munge_cte[0]
+ else:
+ msg.replace_header('content-transfer-encoding', munge_cte[0])
msg.replace_header('content-type', munge_cte[1])
# Write the headers. First we see if the message object wants to
# handle that itself. If not, we'll do it generically.
--- a/Lib/test/test_email/test_email.py
+++ b/Lib/test/test_email/test_email.py
@@ -314,6 +314,41 @@ class TestMessageAPI(TestEmailBase):
g.flatten(msg)
self.assertEqual(fullrepr, s.getvalue())
+ def test_nonascii_as_string_without_cte(self):
+ m = textwrap.dedent("""\
+ MIME-Version: 1.0
+ Content-type: text/plain; charset="iso-8859-1"
+
+ Test if non-ascii messages with no Content-Transfer-Encoding set
+ can be as_string'd:
+ Föö bär
+ """)
+ source = m.encode('iso-8859-1')
+ expected = textwrap.dedent("""\
+ MIME-Version: 1.0
+ Content-type: text/plain; charset="iso-8859-1"
+ Content-Transfer-Encoding: quoted-printable
+
+ Test if non-ascii messages with no Content-Transfer-Encoding set
+ can be as_string'd:
+ F=F6=F6 b=E4r
+ """)
+ msg = email.message_from_bytes(source)
+ self.assertEqual(msg.as_string(), expected)
+
+ def test_nonascii_as_string_without_content_type_and_cte(self):
+ m = textwrap.dedent("""\
+ MIME-Version: 1.0
+
+ Test if non-ascii messages with no Content-Type nor
+ Content-Transfer-Encoding set can be as_string'd:
+ Föö bär
+ """)
+ source = m.encode('iso-8859-1')
+ expected = source.decode('ascii', 'replace')
+ msg = email.message_from_bytes(source)
+ self.assertEqual(msg.as_string(), expected)
+
def test_as_bytes(self):
msg = self._msgobj('msg_01.txt')
with openfile('msg_01.txt') as fp:
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-01-19-18-40-26.bpo-27321.8e6SpM.rst
@@ -0,0 +1,2 @@
+Fixed KeyError exception when flattening an email to a string attempts to
+replace a non-existent Content-Transfer-Encoding header.
