From 371146a3f8a989964e2a9c0efc7d776815410fac Mon Sep 17 00:00:00 2001 From: "Miss Skeleton (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Mon, 19 Oct 2020 16:07:20 -0700 Subject: 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 --- Lib/email/generator.py | 6 +++- Lib/test/test_email/test_email.py | 35 ++++++++++++++++++++++ .../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 diff --git a/Lib/email/generator.py b/Lib/email/generator.py index ae670c2..c9b1216 100644 --- 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. diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py index 9e5c6ad..d262dd0 100644 --- a/Lib/test/test_email/test_email.py +++ b/Lib/test/test_email/test_email.py @@ -311,6 +311,41 @@ 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: diff --git a/Misc/NEWS.d/next/Library/2020-01-19-18-40-26.bpo-27321.8e6SpM.rst b/Misc/NEWS.d/next/Library/2020-01-19-18-40-26.bpo-27321.8e6SpM.rst new file mode 100644 index 0000000..28acf7f --- /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. -- cgit v0.12