Return back old behavior and update doc

Author: hrimov

Doc/library/email.message.rst

@@ -62,12 +62,10 @@ message objects.
    .. note::
 
       The :class:`EmailMessage` class requires a policy that provides a
-      ``content_manager`` attribute (such as :class:`~email.policy.EmailPolicy`)
-      for content management methods like :meth:`set_content` and
-      :meth:`get_content` to work. The legacy :class:`~email.policy.Compat32`
-      policy does not support these methods. To serialize a message with
-      compat32 formatting, construct the message with a modern policy and pass
-      :const:`~email.policy.compat32` to :meth:`as_string` or :meth:`as_bytes`.
+      ``content_manager`` attribute for content management methods like
+      :meth:`set_content` and :meth:`get_content` to work.
+      The legacy :class:`~email.policy.Compat32` policy does not support
+      these methods and should not be used with :class:`EmailMessage`.
 
    .. method:: as_string(unixfrom=False, maxheaderlen=None, policy=None)
 
@@ -613,12 +611,6 @@ message objects.
       *content_manager* is not specified, use the ``content_manager`` specified
       by the current :mod:`~email.policy`.
 
-      .. note::
-
-         This method requires a policy with a ``content_manager`` attribute.
-         The legacy :const:`~email.policy.compat32` policy does not support
-         this method.
-
 
    .. method:: set_content(*args, content_manager=None, **kw)
 
@@ -628,12 +620,6 @@ message objects.
       *content_manager* is not specified, use the ``content_manager`` specified
       by the current :mod:`~email.policy`.
 
-      .. note::
-
-         This method requires a policy with a ``content_manager`` attribute.
-         The legacy :const:`~email.policy.compat32` policy does not support
-         this method.
-
 
    .. method:: make_related(boundary=None)
 

Doc/library/email.policy.rst

@@ -664,15 +664,10 @@ The header objects and their attributes are described in
 
    .. note::
 
-      The :const:`compat32` policy does not provide a ``content_manager``
-      attribute and cannot be used with content management methods like
-      :meth:`~email.message.EmailMessage.set_content` and
-      :meth:`~email.message.EmailMessage.get_content`. To serialize an
-      :class:`~email.message.EmailMessage` with compat32 formatting, construct
-      the message with :data:`~email.policy.default` or another
-      :class:`EmailPolicy` instance, then pass :const:`compat32` to
-      :meth:`~email.message.EmailMessage.as_string` or
-      :meth:`~email.message.EmailMessage.as_bytes`.
+      The :const:`compat32` policy should not be used as a policy for
+      :class:`~email.message.EmailMessage` objects, and should only be used
+      to serialize messages that were created using the :const:`compat32`
+      policy.
 
 
 .. rubric:: Footnotes

Lib/email/message.py

@@ -1136,18 +1136,12 @@ def iter_parts(self):
 
     def get_content(self, *args, content_manager=None, **kw):
         if content_manager is None:
-            content_manager = getattr(self.policy, 'content_manager', None)
-            if content_manager is None:
-                raise TypeError('policy %s lacks content_manager'
-                                % type(self.policy).__name__)
+            content_manager = self.policy.content_manager
         return content_manager.get_content(self, *args, **kw)
 
     def set_content(self, *args, content_manager=None, **kw):
         if content_manager is None:
-            content_manager = getattr(self.policy, 'content_manager', None)
-            if content_manager is None:
-                raise TypeError('policy %s lacks content_manager'
-                                % type(self.policy).__name__)
+            content_manager = self.policy.content_manager
         content_manager.set_content(self, *args, **kw)
 
     def _make_multipart(self, subtype, disallowed_subtypes, boundary):

Lib/test/test_email/test_message.py

@@ -1113,21 +1113,6 @@ def test_string_payload_with_multipart_content_type(self):
         attachments = msg.iter_attachments()
         self.assertEqual(list(attachments), [])
 
-    def test_set_content_with_compat32_policy_raises(self):
-        m = MIMEPart(policy=policy.compat32)
-        with self.assertRaises(TypeError) as cm:
-            m.set_content(b'\x00'*100, 'image', 'png')
-        self.assertIn('content_manager', str(cm.exception))
-
-    def test_set_content_with_compat32_policy_flattening(self):
-        m = MIMEPart()
-        m.set_content(b'\x00'*100, 'image', 'png')
-        message_as_bytes = m.as_bytes(policy=policy.compat32)
-        self.assertEqual(message_as_bytes,
-                         b'Content-Type: image/png\nContent-Transfer-Encoding: base64\n\n'
-                         b'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n'
-                         b'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==\n')
-
 
 if __name__ == '__main__':
     unittest.main()