send_email: Parse emails in a way mypy 1.14 understands.

Signed-off-by: Anders Kaseorg <anders@zulip.com>
(cherry picked from commit 63aaafb94a)

zerver/lib/send_email.py

@@ -6,6 +6,7 @@ from collections.abc import Callable, Mapping
 from contextlib import suppress
 from datetime import timedelta
 from email.headerregistry import Address
+from email.message import EmailMessage
 from email.parser import Parser
 from email.policy import default
 from email.utils import formataddr, parseaddr
@@ -526,7 +527,7 @@ def custom_email_sender(
 ) -> Callable[..., None]:
     with open(markdown_template_path) as f:
         text = f.read()
-        parsed_email_template = Parser(policy=default).parsestr(text)
+        parsed_email_template = Parser(_class=EmailMessage, policy=default).parsestr(text)
         email_template_hash = hashlib.sha256(text.encode()).hexdigest()[0:32]
 
     email_id = f"zerver/emails/custom/custom_email_{email_template_hash}"

zerver/management/commands/email_mirror.py

@@ -18,7 +18,7 @@ recipient address and retrieve, forward, and archive the message.
 
 """
 
-import email
+import email.parser
 import email.policy
 import logging
 from collections.abc import Generator
@@ -69,10 +69,9 @@ def get_imap_messages() -> Generator[EmailMessage, None, None]:
                 status, msg_data = mbox.fetch(message_id, "(RFC822)")
                 assert isinstance(msg_data[0], tuple)
                 msg_as_bytes = msg_data[0][1]
-                message = email.message_from_bytes(msg_as_bytes, policy=email.policy.default)
-                # https://github.com/python/typeshed/issues/2417
-                assert isinstance(message, EmailMessage)
-                yield message
+                yield email.parser.BytesParser(
+                    _class=EmailMessage, policy=email.policy.default
+                ).parsebytes(msg_as_bytes)
                 mbox.store(message_id, "+FLAGS", "\\Deleted")
             mbox.expunge()
         finally:

zerver/management/commands/send_to_email_mirror.py

@@ -1,5 +1,5 @@
 import base64
-import email
+import email.parser
 import email.policy
 import os
 from email.message import EmailMessage
@@ -105,10 +105,9 @@ Example:
             return self._parse_email_json_fixture(fixture_path)
         else:
             with open(fixture_path, "rb") as fp:
-                message = email.message_from_binary_file(fp, policy=email.policy.default)
-                # https://github.com/python/typeshed/issues/2417
-                assert isinstance(message, EmailMessage)
-                return message
+                return email.parser.BytesParser(
+                    _class=EmailMessage, policy=email.policy.default
+                ).parse(fp)
 
     def _prepare_message(self, message: EmailMessage, realm: Realm, stream_name: str) -> None:
         stream = get_stream(stream_name, realm)

zerver/tests/test_email_mirror.py

@@ -1,9 +1,9 @@
 import base64
+import email.parser
 import email.policy
 import os
 import subprocess
 from collections.abc import Callable, Mapping
-from email import message_from_string
 from email.headerregistry import Address
 from email.message import EmailMessage, MIMEPart
 from typing import TYPE_CHECKING, Any
@@ -1639,9 +1639,9 @@ class TestContentTypeUnspecifiedCharset(ZulipTestCase):
         message_as_string = message_as_string.replace(
             'Content-Type: text/plain; charset="us-ascii"', "Content-Type: text/plain"
         )
-        incoming_message = message_from_string(message_as_string, policy=email.policy.default)
-        # https://github.com/python/typeshed/issues/2417
-        assert isinstance(incoming_message, EmailMessage)
+        incoming_message = email.parser.Parser(
+            _class=EmailMessage, policy=email.policy.default
+        ).parsestr(message_as_string)
 
         user_profile = self.example_user("hamlet")
         self.login_user(user_profile)
@@ -1664,9 +1664,9 @@ class TestContentTypeInvalidCharset(ZulipTestCase):
             'Content-Type: text/plain; charset="us-ascii"',
             'Content-Type: text/plain; charset="bogus"',
         )
-        incoming_message = message_from_string(message_as_string, policy=email.policy.default)
-        # https://github.com/python/typeshed/issues/2417
-        assert isinstance(incoming_message, EmailMessage)
+        incoming_message = email.parser.Parser(
+            _class=EmailMessage, policy=email.policy.default
+        ).parsestr(message_as_string)
 
         user_profile = self.example_user("hamlet")
         self.login_user(user_profile)

zerver/worker/email_mirror.py

@@ -1,6 +1,6 @@
 # Documented in https://zulip.readthedocs.io/en/latest/subsystems/queuing.html
 import base64
-import email
+import email.parser
 import email.policy
 import logging
 from collections.abc import Mapping
@@ -26,11 +26,9 @@ class MirrorWorker(QueueProcessingWorker):
     @override
     def consume(self, event: Mapping[str, Any]) -> None:
         rcpt_to = event["rcpt_to"]
-        msg = email.message_from_bytes(
-            base64.b64decode(event["msg_base64"]),
-            policy=email.policy.default,
+        msg = email.parser.BytesParser(_class=EmailMessage, policy=email.policy.default).parsebytes(
+            base64.b64decode(event["msg_base64"])
         )
-        assert isinstance(msg, EmailMessage)  # https://github.com/python/typeshed/issues/2417
         if not is_missed_message_address(rcpt_to):
             # Missed message addresses are one-time use, so we don't need
             # to worry about emails to them resulting in message spam.