Merge pull request #918 from simple-login/handle-error-as-bytes

handle the AttributeError that can also be raised by as_bytes()

.flake8

@@ -6,7 +6,9 @@ extend-ignore =
     E203,
     E501,
     # Ignore "f-string is missing placeholders"
-    F541
+    F541,
+    # allow bare except
+    E722, B001
 exclude =
     .git,
     __pycache__,

app/email_utils.py

@@ -8,9 +8,6 @@ import random
 import time
 import uuid
 from copy import deepcopy
-
-from aiosmtpd.smtp import Envelope
-
 from email import policy, message_from_bytes, message_from_string
 from email.header import decode_header, Header
 from email.message import Message, EmailMessage
@@ -25,6 +22,7 @@ import dkim
 import newrelic.agent
 import re2 as re
 import spf
+from aiosmtpd.smtp import Envelope
 from cachetools import cached, TTLCache
 from email_validator import (
     validate_email,
@@ -843,24 +841,19 @@ def copy(msg: Message) -> Message:
 
 def to_bytes(msg: Message):
     """replace Message.as_bytes() method by trying different policies"""
-    try:
+    for generator_policy in [None, policy.SMTP, policy.SMTPUTF8]:
-        return msg.as_bytes()
-    except UnicodeEncodeError:
-        LOG.w("as_bytes fails with default policy, try SMTP policy")
         try:
-            return msg.as_bytes(policy=policy.SMTP)
+            return msg.as_bytes(policy=generator_policy)
-        except UnicodeEncodeError:
+        except:
-            LOG.w("as_bytes fails with SMTP policy, try SMTPUTF8 policy")
+            LOG.w("as_bytes() fails with %s policy", policy, exc_info=True)
-            try:
+
-                return msg.as_bytes(policy=policy.SMTPUTF8)
+    msg_string = msg.as_string()
-            except UnicodeEncodeError:
+    try:
-                LOG.w("as_bytes fails with SMTPUTF8 policy, try converting to string")
+        return msg_string.encode()
-                msg_string = msg.as_string()
+    except:
-                try:
+        LOG.w("as_string().encode() fails", exc_info=True)
-                    return msg_string.encode()
+
-                except UnicodeEncodeError as e:
+    return msg_string.encode(errors="replace")
-                    LOG.w("can't encode msg, err:%s", e)
-                    return msg_string.encode(errors="replace")
 
 
 def should_add_dkim_signature(domain: str) -> bool: