Include an In-Reply-To: <Message-ID of triggering e-mail>, if any, in the new_ticket notification

todosrht-lmtp

@@ -106,7 +106,8 @@ class MailHandler:
             print("Rejecting email due to validation errors")
             return "550 " + ", ".join([e["reason"] for e in valid.errors])
 
-        ticket = submit_ticket(tracker, sender, title, desc, from_email=True)
+        ticket = submit_ticket(tracker, sender, title, desc,
+                from_email=True, from_email_id=mail["Message-ID"])
         UserWebhook.deliver(UserWebhook.Events.ticket_create,
                 ticket.to_dict(),
                 UserWebhook.Subscription.user_id == sender.id)

todosrht/tickets.py

@@ -433,7 +433,7 @@ def get_comment_counts(tickets):
         .filter(col.in_([t.id for t in tickets]))
         .group_by(col))
 
-def _send_new_ticket_notification(subscription, ticket):
+def _send_new_ticket_notification(subscription, ticket, email_trigger_id):
     subject = f"{ticket.ref()}: {ticket.title}"
     headers = {
         "From": "{} <{}>".format(ticket.submitter.name, notify_from),
@@ -441,11 +441,14 @@ def _send_new_ticket_notification(subscription, ticket):
         "Reply-To": f"{ticket.ref()} <{ticket.ref(email=True)}@{posting_domain}>",
         "Sender": smtp_user,
     }
+    if email_trigger_id:
+        headers["In-Reply-To"] = email_trigger_id
 
     notify(subscription, "new_ticket", subject,
         headers=headers, ticket=ticket, ticket_url=ticket_url(ticket))
 
-def submit_ticket(tracker, submitter, title, description, importing=False, from_email=False):
+def submit_ticket(tracker, submitter, title, description,
+        importing=False, from_email=False, from_email_id=None):
     ticket = Ticket(
         submitter=submitter,
         tracker=tracker,
@@ -473,7 +476,7 @@ def submit_ticket(tracker, submitter, title, description, importing=False, from_
             _create_event_notification(sub.participant, event)
             # Notify submitter for tickets created by email
             if from_email or sub.participant != submitter:
-                _send_new_ticket_notification(sub, ticket)
+                _send_new_ticket_notification(sub, ticket, from_email_id)
 
         notified_users = [sub.participant for sub in tracker.subscriptions]
         _handle_mentions(