From 2a77a910eb16333e56b85a7fdb3d6254acc9b6d7 Mon Sep 17 00:00:00 2001
From: Till <2353100+S7evinK@users.noreply.github.com>
Date: Mon, 14 Nov 2022 13:07:13 +0100
Subject: [PATCH] Handle remote room upgrades (#2866)

Makes the following tests pass
```
/upgrade moves remote aliases to the new room
Local and remote users' homeservers remove a room from their public directory on upgrade
```
---
 roomserver/internal/input/input_events.go | 16 ++++++++++++
 roomserver/storage/interface.go           |  1 +
 roomserver/storage/shared/storage.go      | 30 +++++++++++++++++++++++
 sytest-whitelist                          |  4 ++-
 4 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/roomserver/internal/input/input_events.go b/roomserver/internal/input/input_events.go
index 60160e8e5..682aa2b12 100644
--- a/roomserver/internal/input/input_events.go
+++ b/roomserver/internal/input/input_events.go
@@ -23,6 +23,8 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/tidwall/gjson"
+
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
 	"github.com/opentracing/opentracing-go"
@@ -409,6 +411,13 @@ func (r *Inputer) processRoomEvent(
 		}
 	}
 
+	// Handle remote room upgrades, e.g. remove published room
+	if event.Type() == "m.room.tombstone" && event.StateKeyEquals("") && !r.Cfg.Matrix.IsLocalServerName(senderDomain) {
+		if err = r.handleRemoteRoomUpgrade(ctx, event); err != nil {
+			return fmt.Errorf("failed to handle remote room upgrade: %w", err)
+		}
+	}
+
 	// processing this event resulted in an event (which may not be the one we're processing)
 	// being redacted. We are guaranteed to have both sides (the redaction/redacted event),
 	// so notify downstream components to redact this event - they should have it if they've
@@ -434,6 +443,13 @@ func (r *Inputer) processRoomEvent(
 	return nil
 }
 
+// handleRemoteRoomUpgrade updates published rooms and room aliases
+func (r *Inputer) handleRemoteRoomUpgrade(ctx context.Context, event *gomatrixserverlib.Event) error {
+	oldRoomID := event.RoomID()
+	newRoomID := gjson.GetBytes(event.Content(), "replacement_room").Str
+	return r.DB.UpgradeRoom(ctx, oldRoomID, newRoomID, event.Sender())
+}
+
 // processStateBefore works out what the state is before the event and
 // then checks the event auths against the state at the time. It also
 // tries to determine what the history visibility was of the event at
diff --git a/roomserver/storage/interface.go b/roomserver/storage/interface.go
index c39a8cbba..06db4b2d8 100644
--- a/roomserver/storage/interface.go
+++ b/roomserver/storage/interface.go
@@ -172,4 +172,5 @@ type Database interface {
 	ForgetRoom(ctx context.Context, userID, roomID string, forget bool) error
 
 	GetHistoryVisibilityState(ctx context.Context, roomInfo *types.RoomInfo, eventID string, domain string) ([]*gomatrixserverlib.Event, error)
+	UpgradeRoom(ctx context.Context, oldRoomID, newRoomID, eventSender string) error
 }
diff --git a/roomserver/storage/shared/storage.go b/roomserver/storage/shared/storage.go
index 9bf438a23..16898bcb1 100644
--- a/roomserver/storage/shared/storage.go
+++ b/roomserver/storage/shared/storage.go
@@ -1408,6 +1408,36 @@ func (d *Database) ForgetRoom(ctx context.Context, userID, roomID string, forget
 	})
 }
 
+func (d *Database) UpgradeRoom(ctx context.Context, oldRoomID, newRoomID, eventSender string) error {
+
+	return d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
+		// un-publish old room
+		if err := d.PublishedTable.UpsertRoomPublished(ctx, txn, oldRoomID, "", "", false); err != nil {
+			return fmt.Errorf("failed to unpublish room: %w", err)
+		}
+		// publish new room
+		if err := d.PublishedTable.UpsertRoomPublished(ctx, txn, newRoomID, "", "", true); err != nil {
+			return fmt.Errorf("failed to publish room: %w", err)
+		}
+
+		// Migrate any existing room aliases
+		aliases, err := d.RoomAliasesTable.SelectAliasesFromRoomID(ctx, txn, oldRoomID)
+		if err != nil {
+			return fmt.Errorf("failed to get room aliases: %w", err)
+		}
+
+		for _, alias := range aliases {
+			if err = d.RoomAliasesTable.DeleteRoomAlias(ctx, txn, alias); err != nil {
+				return fmt.Errorf("failed to remove room alias: %w", err)
+			}
+			if err = d.RoomAliasesTable.InsertRoomAlias(ctx, txn, alias, newRoomID, eventSender); err != nil {
+				return fmt.Errorf("failed to set room alias: %w", err)
+			}
+		}
+		return nil
+	})
+}
+
 // FIXME TODO: Remove all this - horrible dupe with roomserver/state. Can't use the original impl because of circular loops
 // it should live in this package!
 
diff --git a/sytest-whitelist b/sytest-whitelist
index bb4f0a279..49ffb8fe8 100644
--- a/sytest-whitelist
+++ b/sytest-whitelist
@@ -761,4 +761,6 @@ AS can publish rooms in their own list
 AS and main public room lists are separate
 /upgrade preserves direct room state
 local user has tags copied to the new room
-remote user has tags copied to the new room
\ No newline at end of file
+remote user has tags copied to the new room
+/upgrade moves remote aliases to the new room
+Local and remote users' homeservers remove a room from their public directory on upgrade
\ No newline at end of file