From 1cd285dee0d19f48ec55143d7c37cca43dbdf075 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Wed, 22 Oct 2025 15:51:35 +0300
Subject: [PATCH] bridgev2/matrixinvite: allow redirecting created DM to no
 ghost

---
 bridgev2/matrixinvite.go     | 11 +++++++----
 bridgev2/networkinterface.go |  3 +++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/bridgev2/matrixinvite.go b/bridgev2/matrixinvite.go
index 2c14cc7f..05479a3c 100644
--- a/bridgev2/matrixinvite.go
+++ b/bridgev2/matrixinvite.go
@@ -221,6 +221,7 @@ func (br *Bridge) handleGhostDMInvite(ctx context.Context, evt *event.Event, sen
 		rejectInvite(ctx, evt, br.Bot, "")
 		return EventHandlingResultSuccess
 	}
+	overrideIntent := invitedGhost.Intent
 	if resp.DMRedirectedTo != "" && resp.DMRedirectedTo != invitedGhost.ID {
 		log.Debug().
 			Str("dm_redirected_to_id", string(resp.DMRedirectedTo)).
@@ -234,11 +235,13 @@ func (br *Bridge) handleGhostDMInvite(ctx context.Context, evt *event.Event, sen
 		if err != nil {
 			log.Err(err).Msg("Failed to make incorrect ghost leave new DM room")
 		}
-		otherUserGhost, err := br.GetGhostByID(ctx, resp.DMRedirectedTo)
-		if err != nil {
+		if resp.DMRedirectedTo != SpecialValueDMRedirectedToBot {
+			overrideIntent = br.Bot
+		} else if otherUserGhost, err := br.GetGhostByID(ctx, resp.DMRedirectedTo); err != nil {
 			log.Err(err).Msg("Failed to get ghost of real portal other user ID")
 		} else {
 			invitedGhost = otherUserGhost
+			overrideIntent = otherUserGhost.Intent
 		}
 	}
 	err = portal.UpdateMatrixRoomID(ctx, evt.RoomID, UpdateMatrixRoomIDParams{
@@ -251,7 +254,7 @@ func (br *Bridge) handleGhostDMInvite(ctx context.Context, evt *event.Event, sen
 	})
 	if err != nil {
 		log.Err(err).Msg("Failed to update Matrix room ID for new DM portal")
-		sendNotice(ctx, evt, invitedGhost.Intent, "Failed to finish configuring portal. The chat may or may not work")
+		sendNotice(ctx, evt, overrideIntent, "Failed to finish configuring portal. The chat may or may not work")
 		return EventHandlingResultSuccess
 	}
 	message := "Private chat portal created"
@@ -263,7 +266,7 @@ func (br *Bridge) handleGhostDMInvite(ctx context.Context, evt *event.Event, sen
 			message += fmt.Sprintf("\n\nWarning: %s", err.Error())
 		}
 	}
-	sendNotice(ctx, evt, invitedGhost.Intent, message)
+	sendNotice(ctx, evt, overrideIntent, message)
 	return EventHandlingResultSuccess
 }
 
diff --git a/bridgev2/networkinterface.go b/bridgev2/networkinterface.go
index 4d2f2edf..9ca2dc43 100644
--- a/bridgev2/networkinterface.go
+++ b/bridgev2/networkinterface.go
@@ -16,6 +16,7 @@ import (
 	"github.com/rs/zerolog"
 	"go.mau.fi/util/configupgrade"
 	"go.mau.fi/util/ptr"
+	"go.mau.fi/util/random"
 
 	"maunium.net/go/mautrix/bridgev2/database"
 	"maunium.net/go/mautrix/bridgev2/networkid"
@@ -724,6 +725,8 @@ type ResolveIdentifierResponse struct {
 	Chat *CreateChatResponse
 }
 
+var SpecialValueDMRedirectedToBot = networkid.UserID("__fi.mau.bridgev2.dm_redirected_to_bot::" + random.String(10))
+
 type CreateChatResponse struct {
 	PortalKey networkid.PortalKey
 	// Portal and PortalInfo are not required, the caller will fetch them automatically based on PortalKey if necessary.