Issue 7970: When email.Parser.Parser parses a MIME message of type

message/rfc822 it turns it into an object whose body consists of
a list containing a single Message object.  HeaderParser, on the
other hand, just copies the body as a string.  Generator.flatten
has a special handler for the message mime type that expected the
body to be the one item list.  This fails if the message was parsed
by HeaderParser.  So we now check to see if the body is a string
first, and if so just we just emit it.

1 files changed, 12 insertions, 0 deletions

diff --git a/Lib/email/test/test_email.py b/Lib/email/test/test_email.py
index f1a218d..aa16ce2 100644
--- a/Lib/email/test/test_email.py
+++ b/Lib/email/test/test_email.py
@@ -179,6 +179,18 @@ class TestMessageAPI(TestEmailBase):
         self.assertRaises(Errors.HeaderParseError,
                           msg.set_boundary, 'BOUNDARY')
 
+    def test_message_rfc822_only(self):
+        # Issue 7970: message/rfc822 not in multipart parsed by
+        # HeaderParser caused an exception when flattened.
+        fp = openfile(findfile('msg_46.txt'))
+        msgdata = fp.read()
+        parser = email.Parser.HeaderParser()
+        msg = parser.parsestr(msgdata)
+        out = StringIO()
+        gen = email.Generator.Generator(out, True, 0)
+        gen.flatten(msg, False)
+        self.assertEqual(out.getvalue(), msgdata)
+
     def test_get_decoded_payload(self):
         eq = self.assertEqual
         msg = self._msgobj('msg_10.txt')