Fix: use MIMEBase for email attachments (#8762)

src/documents/signals/handlers.py

@@ -12,7 +12,6 @@ from celery.signals import task_postrun
 from celery.signals import task_prerun
 from django.conf import settings
 from django.contrib.auth.models import User
-from django.core.mail import EmailMessage
 from django.db import DatabaseError
 from django.db import close_old_connections
 from django.db import models
@@ -30,6 +29,7 @@ from documents.data_models import DocumentMetadataOverrides
 from documents.file_handling import create_source_path_directory
 from documents.file_handling import delete_empty_directories
 from documents.file_handling import generate_unique_filename
+from documents.mail import send_email
 from documents.models import Correspondent
 from documents.models import CustomField
 from documents.models import CustomFieldInstance
@@ -972,17 +972,13 @@ def run_workflows(
             doc_url,
         )
         try:
-            email = EmailMessage(
+            n_messages = send_email(
                 subject=subject,
                 body=body,
                 to=action.email.to.split(","),
+                attachment=original_file if action.email.include_document else None,
+                attachment_mime_type=document.mime_type,
             )
-            if action.email.include_document:
-                # Something could be renaming the file concurrently so it can't be attached
-                with FileLock(settings.MEDIA_LOCK):
-                    document.refresh_from_db()
-                    email.attach_file(original_file)
-            n_messages = email.send()
             logger.debug(
                 f"Sent {n_messages} notification email(s) to {action.email.to}",
                 extra={"group": logging_group},