Emit redacted_event from the roomserver when redactions are validated (#1186)

* Emit redacted_event from the roomserver when redactions are validated

- Consume them in the currentstateserver and act accordingly.
- Add integration test for the roomserver to check that injecting
  `m.room.redaction` events result in `redacted_event` being emitted.

* Linting

* Ignore events that redact themselves

currentstateserver/consumers/roomserver.go

@@ -61,6 +61,8 @@ func (c *OutputRoomEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
 		return c.onNewRoomEvent(context.TODO(), *output.NewRoomEvent)
 	case api.OutputTypeNewInviteEvent:
 	case api.OutputTypeRetireInviteEvent:
+	case api.OutputTypeRedactedEvent:
+		return c.onRedactEvent(context.Background(), *output.RedactedEvent)
 	default:
 		log.WithField("type", output.Type).Debug(
 			"roomserver output log: ignoring unknown output type",
@@ -105,6 +107,12 @@ func (c *OutputRoomEventConsumer) onNewRoomEvent(
 	return nil
 }
 
+func (c *OutputRoomEventConsumer) onRedactEvent(
+	ctx context.Context, msg api.OutputRedactedEvent,
+) error {
+	return c.db.RedactEvent(ctx, msg.RedactedEventID, msg.RedactedBecause)
+}
+
 // Start consuming from room servers
 func (c *OutputRoomEventConsumer) Start() error {
 	return c.rsConsumer.Start()

currentstateserver/storage/interface.go

@@ -35,4 +35,6 @@ type Database interface {
 	// GetBulkStateContent returns all state events which match a given room ID and a given state key tuple. Both must be satisfied for a match.
 	// If a tuple has the StateKey of '*' and allowWildcards=true then all state events with the EventType should be returned.
 	GetBulkStateContent(ctx context.Context, roomIDs []string, tuples []gomatrixserverlib.StateKeyTuple, allowWildcards bool) ([]tables.StrippedEvent, error)
+	// Redact a state event
+	RedactEvent(ctx context.Context, redactedEventID string, redactedBecause gomatrixserverlib.HeaderedEvent) error
 }

currentstateserver/storage/postgres/current_room_state_table.go

@@ -189,7 +189,6 @@ func (s *currentRoomStateStatements) SelectEventsWithEventIDs(
 		if err := rows.Scan(&eventBytes); err != nil {
 			return nil, err
 		}
-		// TODO: Handle redacted events
 		var ev gomatrixserverlib.HeaderedEvent
 		if err := json.Unmarshal(eventBytes, &ev); err != nil {
 			return nil, err

currentstateserver/storage/shared/storage.go

@@ -17,10 +17,13 @@ package shared
 import (
 	"context"
 	"database/sql"
+	"fmt"
 
 	"github.com/matrix-org/dendrite/currentstateserver/storage/tables"
+	"github.com/matrix-org/dendrite/internal/eventutil"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
 )
 
 type Database struct {
@@ -36,6 +39,28 @@ func (d *Database) GetBulkStateContent(ctx context.Context, roomIDs []string, tu
 	return d.CurrentRoomState.SelectBulkStateContent(ctx, roomIDs, tuples, allowWildcards)
 }
 
+func (d *Database) RedactEvent(ctx context.Context, redactedEventID string, redactedBecause gomatrixserverlib.HeaderedEvent) error {
+	events, err := d.CurrentRoomState.SelectEventsWithEventIDs(ctx, nil, []string{redactedEventID})
+	if err != nil {
+		return err
+	}
+	if len(events) != 1 {
+		// this should never happen but is non-fatal
+		util.GetLogger(ctx).WithField("redacted_event_id", redactedEventID).WithField("redaction_event_id", redactedBecause.EventID()).Warnf(
+			"RedactEvent: missing redacted event",
+		)
+		return nil
+	}
+	redactionEvent := redactedBecause.Unwrap()
+	eventBeingRedacted := events[0].Unwrap()
+	redactedEvent, err := eventutil.RedactEvent(&redactionEvent, &eventBeingRedacted)
+	if err != nil {
+		return fmt.Errorf("RedactEvent failed: %w", err)
+	}
+	// replace the state event with a redacted version of itself
+	return d.StoreStateEvents(ctx, []gomatrixserverlib.HeaderedEvent{redactedEvent.Headered(redactedBecause.RoomVersion)}, []string{redactedEventID})
+}
+
 func (d *Database) StoreStateEvents(ctx context.Context, addStateEvents []gomatrixserverlib.HeaderedEvent,
 	removeStateEventIDs []string) error {
 	return sqlutil.WithTransaction(d.DB, func(txn *sql.Tx) error {

currentstateserver/storage/sqlite3/current_room_state_table.go

@@ -162,7 +162,13 @@ func (s *currentRoomStateStatements) SelectEventsWithEventIDs(
 		iEventIDs[k] = v
 	}
 	query := strings.Replace(selectEventsWithEventIDsSQL, "($1)", sqlutil.QueryVariadic(len(iEventIDs)), 1)
-	rows, err := txn.QueryContext(ctx, query, iEventIDs...)
+	var rows *sql.Rows
+	var err error
+	if txn != nil {
+		rows, err = txn.QueryContext(ctx, query, iEventIDs...)
+	} else {
+		rows, err = s.db.QueryContext(ctx, query, iEventIDs...)
+	}
 	if err != nil {
 		return nil, err
 	}
@@ -173,7 +179,6 @@ func (s *currentRoomStateStatements) SelectEventsWithEventIDs(
 		if err := rows.Scan(&eventBytes); err != nil {
 			return nil, err
 		}
-		// TODO: Handle redacted events
 		var ev gomatrixserverlib.HeaderedEvent
 		if err := json.Unmarshal(eventBytes, &ev); err != nil {
 			return nil, err

currentstateserver/storage/tables/interface.go

@@ -24,6 +24,8 @@ import (
 
 type CurrentRoomState interface {
 	SelectStateEvent(ctx context.Context, roomID, evType, stateKey string) (*gomatrixserverlib.HeaderedEvent, error)
+	// SelectEventsWithEventIDs returns the events for the given event IDs. If the event(s) are missing, they are not returned
+	// and no error is returned.
 	SelectEventsWithEventIDs(ctx context.Context, txn *sql.Tx, eventIDs []string) ([]gomatrixserverlib.HeaderedEvent, error)
 	// UpsertRoomState stores the given event in the database, along with an extracted piece of content.
 	// The piece of content will vary depending on the event type, and table implementations may use this information to optimise

go.mod

@@ -21,7 +21,7 @@ require (
 	github.com/matrix-org/go-http-js-libp2p v0.0.0-20200518170932-783164aeeda4
 	github.com/matrix-org/go-sqlite3-js v0.0.0-20200522092705-bc8506ccbcf3
 	github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26
-	github.com/matrix-org/gomatrixserverlib v0.0.0-20200630110352-4948932681fe
+	github.com/matrix-org/gomatrixserverlib v0.0.0-20200707103800-7470b03f069b
 	github.com/matrix-org/naffka v0.0.0-20200422140631-181f1ee7401f
 	github.com/matrix-org/util v0.0.0-20190711121626-527ce5ddefc7
 	github.com/mattn/go-sqlite3 v2.0.2+incompatible

go.sum

@@ -421,8 +421,8 @@ github.com/matrix-org/go-sqlite3-js v0.0.0-20200522092705-bc8506ccbcf3 h1:Yb+Wlf
 github.com/matrix-org/go-sqlite3-js v0.0.0-20200522092705-bc8506ccbcf3/go.mod h1:e+cg2q7C7yE5QnAXgzo512tgFh1RbQLC0+jozuegKgo=
 github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26 h1:Hr3zjRsq2bhrnp3Ky1qgx/fzCtCALOoGYylh2tpS9K4=
 github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26/go.mod h1:3fxX6gUjWyI/2Bt7J1OLhpCzOfO/bB3AiX0cJtEKud0=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20200630110352-4948932681fe h1:rCjG+azihYsO+EIdm//Zx5gQ7hzeJVraeSukLsW1Mic=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20200707103800-7470b03f069b h1:g1ueoPHI5tpafw/QysVfDw43FwRTPqz8sT+MZbK54yk=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20200630110352-4948932681fe/go.mod h1:JsAzE1Ll3+gDWS9JSUHPJiiyAksvOOnGWF2nXdg4ZzU=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20200707103800-7470b03f069b/go.mod h1:JsAzE1Ll3+gDWS9JSUHPJiiyAksvOOnGWF2nXdg4ZzU=
 github.com/matrix-org/naffka v0.0.0-20200422140631-181f1ee7401f h1:pRz4VTiRCO4zPlEMc3ESdUOcW4PXHH4Kj+YDz1XyE+Y=
 github.com/matrix-org/naffka v0.0.0-20200422140631-181f1ee7401f/go.mod h1:y0oDTjZDv5SM9a2rp3bl+CU+bvTRINQsdb7YlDql5Go=
 github.com/matrix-org/util v0.0.0-20190711121626-527ce5ddefc7 h1:ntrLa/8xVzeSs8vHFHK25k0C+NV74sYMJnNSg5NoSRo=

internal/eventutil/events.go

@@ -149,3 +149,18 @@ func truncateAuthAndPrevEvents(auth, prev []gomatrixserverlib.EventReference) (
 	}
 	return
 }
+
+// RedactEvent redacts the given event and sets the unsigned field appropriately. This should be used by
+// downstream components to the roomserver when an OutputTypeRedactedEvent occurs.
+func RedactEvent(redactionEvent, redactedEvent *gomatrixserverlib.Event) (*gomatrixserverlib.Event, error) {
+	// sanity check
+	if redactionEvent.Type() != gomatrixserverlib.MRoomRedaction {
+		return nil, fmt.Errorf("RedactEvent: redactionEvent isn't a redaction event, is '%s'", redactionEvent.Type())
+	}
+	r := redactedEvent.Redact()
+	err := r.SetUnsignedField("redacted_because", redactionEvent)
+	if err != nil {
+		return nil, err
+	}
+	return &r, nil
+}

roomserver/api/output.go

@@ -28,6 +28,8 @@ const (
 	OutputTypeNewInviteEvent OutputType = "new_invite_event"
 	// OutputTypeRetireInviteEvent indicates that the event is an OutputRetireInviteEvent
 	OutputTypeRetireInviteEvent OutputType = "retire_invite_event"
+	// OutputTypeRedactedEvent indicates that the event is an OutputRedactedEvent
+	OutputTypeRedactedEvent OutputType = "redacted_event"
 )
 
 // An OutputEvent is an entry in the roomserver output kafka log.
@@ -41,6 +43,8 @@ type OutputEvent struct {
 	NewInviteEvent *OutputNewInviteEvent `json:"new_invite_event,omitempty"`
 	// The content of event with type OutputTypeRetireInviteEvent
 	RetireInviteEvent *OutputRetireInviteEvent `json:"retire_invite_event,omitempty"`
+	// The content of event with type  OutputTypeRedactedEvent
+	RedactedEvent *OutputRedactedEvent `json:"redacted_event,omitempty"`
 }
 
 // An OutputNewRoomEvent is written when the roomserver receives a new event.
@@ -165,3 +169,13 @@ type OutputRetireInviteEvent struct {
 	// "leave" or "ban".
 	Membership string
 }
+
+// An OutputRedactedEvent is written whenever a redaction has been /validated/.
+// Downstream components MUST redact the given event ID if they have stored the
+// event JSON. It is guaranteed that this event ID has been seen before.
+type OutputRedactedEvent struct {
+	// The event ID that was redacted
+	RedactedEventID string
+	// The value of `unsigned.redacted_because` - the redaction event itself
+	RedactedBecause gomatrixserverlib.HeaderedEvent
+}

roomserver/internal/input_events.go

@@ -19,6 +19,7 @@ package internal
 import (
 	"context"
 
+	"github.com/matrix-org/dendrite/internal/eventutil"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/state"
 	"github.com/matrix-org/dendrite/roomserver/types"
@@ -31,6 +32,8 @@ import (
 // TODO(#375): This should be rewritten to allow concurrent calls. The
 // difficulty is in ensuring that we correctly annotate events with the correct
 // state deltas when sending to kafka streams
+// TODO: Break up function - we should probably do transaction ID checks before calling this.
+// nolint:gocyclo
 func (r *RoomserverInternalAPI) processRoomEvent(
 	ctx context.Context,
 	input api.InputRoomEvent,
@@ -60,10 +63,18 @@ func (r *RoomserverInternalAPI) processRoomEvent(
 	}
 
 	// Store the event.
-	roomNID, stateAtEvent, err := r.DB.StoreEvent(ctx, event, input.TransactionID, authEventNIDs)
+	roomNID, stateAtEvent, redactionEvent, redactedEventID, err := r.DB.StoreEvent(ctx, event, input.TransactionID, authEventNIDs)
 	if err != nil {
 		return
 	}
+	// if storing this event results in it being redacted then do so.
+	if redactedEventID == event.EventID() {
+		r, rerr := eventutil.RedactEvent(redactionEvent, &event)
+		if rerr != nil {
+			return "", rerr
+		}
+		event = *r
+	}
 
 	// For outliers we can stop after we've stored the event itself as it
 	// doesn't have any associated state to store and we don't need to
@@ -97,6 +108,25 @@ func (r *RoomserverInternalAPI) processRoomEvent(
 		return
 	}
 
+	// 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
+	// been tracking our output log.
+	if redactedEventID != "" {
+		err = r.WriteOutputEvents(event.RoomID(), []api.OutputEvent{
+			{
+				Type: api.OutputTypeRedactedEvent,
+				RedactedEvent: &api.OutputRedactedEvent{
+					RedactedEventID: redactedEventID,
+					RedactedBecause: redactionEvent.Headered(headered.RoomVersion),
+				},
+			},
+		})
+		if err != nil {
+			return
+		}
+	}
+
 	// Update the extremities of the event graph for the room
 	return event.EventID(), nil
 }

roomserver/internal/query.go

@@ -880,11 +880,24 @@ func persistEvents(ctx context.Context, db storage.Database, events []gomatrixse
 			i++
 		}
 		var stateAtEvent types.StateAtEvent
-		roomNID, stateAtEvent, err = db.StoreEvent(ctx, ev.Unwrap(), nil, authNids)
+		var redactedEventID string
+		var redactionEvent *gomatrixserverlib.Event
+		roomNID, stateAtEvent, redactionEvent, redactedEventID, err = db.StoreEvent(ctx, ev.Unwrap(), nil, authNids)
 		if err != nil {
 			logrus.WithError(err).WithField("event_id", ev.EventID()).Error("Failed to persist event")
 			continue
 		}
+		// If storing this event results in it being redacted, then do so.
+		// It's also possible for this event to be a redaction which results in another event being
+		// redacted, which we don't care about since we aren't returning it in this backfill.
+		if redactedEventID == ev.EventID() {
+			ev = ev.Redact().Headered(ev.RoomVersion)
+			err = ev.SetUnsignedField("redacted_because", redactionEvent)
+			if err != nil {
+				logrus.WithError(err).WithField("event_id", ev.EventID()).Error("Failed to set unsigned field")
+				continue
+			}
+		}
 		backfilledEventMap[ev.EventID()] = types.Event{
 			EventNID: stateAtEvent.StateEntry.EventNID,
 			Event:    ev.Unwrap(),

roomserver/roomserver_test.go

@@ -0,0 +1,173 @@
+package roomserver
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+	"reflect"
+	"testing"
+
+	"github.com/Shopify/sarama"
+	"github.com/matrix-org/dendrite/internal/caching"
+	"github.com/matrix-org/dendrite/internal/config"
+	"github.com/matrix-org/dendrite/internal/setup"
+	"github.com/matrix-org/dendrite/internal/test"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const (
+	testOrigin = gomatrixserverlib.ServerName("kaer.morhen")
+	// we have to use an on-disk DB because we open multiple connections due to the *Updater structs.
+	// Using :memory: results in a brand new DB for each open connection, and sharing memory via
+	// ?cache=shared just allows read-only sharing, so writes to the database on other connections are lost.
+	roomserverDBFileURI  = "file:roomserver_test.db"
+	roomserverDBFilePath = "./roomserver_test.db"
+)
+
+var (
+	ctx = context.Background()
+)
+
+type dummyProducer struct {
+	topic            string
+	producedMessages []*api.OutputEvent
+}
+
+// SendMessage produces a given message, and returns only when it either has
+// succeeded or failed to produce. It will return the partition and the offset
+// of the produced message, or an error if the message failed to produce.
+func (p *dummyProducer) SendMessage(msg *sarama.ProducerMessage) (partition int32, offset int64, err error) {
+	if msg.Topic != p.topic {
+		return 0, 0, nil
+	}
+	be := msg.Value.(sarama.ByteEncoder)
+	b := json.RawMessage(be)
+	fmt.Println("SENDING >>>>>>>> ", string(b))
+	var out api.OutputEvent
+	err = json.Unmarshal(b, &out)
+	if err != nil {
+		return 0, 0, err
+	}
+	p.producedMessages = append(p.producedMessages, &out)
+	return 0, 0, nil
+}
+
+// SendMessages produces a given set of messages, and returns only when all
+// messages in the set have either succeeded or failed. Note that messages
+// can succeed and fail individually; if some succeed and some fail,
+// SendMessages will return an error.
+func (p *dummyProducer) SendMessages(msgs []*sarama.ProducerMessage) error {
+	for _, m := range msgs {
+		p.SendMessage(m)
+	}
+	return nil
+}
+
+// Close shuts down the producer and waits for any buffered messages to be
+// flushed. You must call this function before a producer object passes out of
+// scope, as it may otherwise leak memory. You must call this before calling
+// Close on the underlying client.
+func (p *dummyProducer) Close() error {
+	return nil
+}
+
+func deleteDatabase() {
+	err := os.Remove(roomserverDBFilePath)
+	if err != nil {
+		fmt.Printf("failed to delete database %s: %s\n", roomserverDBFilePath, err)
+	}
+}
+
+func mustLoadEvents(t *testing.T, ver gomatrixserverlib.RoomVersion, events []json.RawMessage) []gomatrixserverlib.HeaderedEvent {
+	hs := make([]gomatrixserverlib.HeaderedEvent, len(events))
+	for i := range events {
+		e, err := gomatrixserverlib.NewEventFromTrustedJSON(events[i], false, ver)
+		if err != nil {
+			t.Fatalf("cannot load test data: " + err.Error())
+		}
+		h := e.Headered(ver)
+		hs[i] = h
+	}
+	return hs
+}
+
+func mustSendEvents(t *testing.T, ver gomatrixserverlib.RoomVersion, events []json.RawMessage) (api.RoomserverInternalAPI, *dummyProducer, []gomatrixserverlib.HeaderedEvent) {
+	cfg := &config.Dendrite{}
+	cfg.Database.RoomServer = roomserverDBFileURI
+	cfg.Kafka.Topics.OutputRoomEvent = "output_room_event"
+	cfg.Matrix.ServerName = testOrigin
+	cfg.Kafka.UseNaffka = true
+	dp := &dummyProducer{
+		topic: string(cfg.Kafka.Topics.OutputRoomEvent),
+	}
+	cache, err := caching.NewInMemoryLRUCache(true)
+	if err != nil {
+		t.Fatalf("failed to make caches: %s", err)
+	}
+	base := &setup.BaseDendrite{
+		KafkaProducer: dp,
+		Caches:        cache,
+		Cfg:           cfg,
+	}
+
+	rsAPI := NewInternalAPI(base, &test.NopJSONVerifier{}, nil)
+	hevents := mustLoadEvents(t, ver, events)
+	_, err = api.SendEvents(ctx, rsAPI, hevents, testOrigin, nil)
+	if err != nil {
+		t.Errorf("failed to SendEvents: %s", err)
+	}
+	return rsAPI, dp, hevents
+}
+
+func TestOutputRedactedEvent(t *testing.T) {
+	redactionEvents := []json.RawMessage{
+		// create event
+		[]byte(`{"auth_events":[],"content":{"creator":"@userid:kaer.morhen"},"depth":0,"event_id":"$N4us6vqqq3RjvpKd:kaer.morhen","hashes":{"sha256":"WTdrCn/YsiounXcJPsLP8xT0ZjHiO5Ov0NvXYmK2onE"},"origin":"kaer.morhen","origin_server_ts":0,"prev_events":[],"prev_state":[],"room_id":"!roomid:kaer.morhen","sender":"@userid:kaer.morhen","signatures":{"kaer.morhen":{"ed25519:auto":"9+5JcpaN5b5KlHYHGp6r+GoNDH98lbfzGYwjfxensa5C5D/bDACaYnMDLnhwsHOE5nxgI+jT/GV271pz6PMSBQ"}},"state_key":"","type":"m.room.create"}`),
+		// join event
+		[]byte(`{"auth_events":[["$N4us6vqqq3RjvpKd:kaer.morhen",{"sha256":"SylirfgfXFhscZL7p10NmOa1nFFEckiwz0lAideQMIM"}]],"content":{"membership":"join"},"depth":1,"event_id":"$6sUiGPQ0a3tqYGKo:kaer.morhen","hashes":{"sha256":"eYVBC7RO+FlxRyW1aXYf/ad4Dzi7T93tArdGw3r4RwQ"},"origin":"kaer.morhen","origin_server_ts":0,"prev_events":[["$N4us6vqqq3RjvpKd:kaer.morhen",{"sha256":"SylirfgfXFhscZL7p10NmOa1nFFEckiwz0lAideQMIM"}]],"prev_state":[],"room_id":"!roomid:kaer.morhen","sender":"@userid:kaer.morhen","signatures":{"kaer.morhen":{"ed25519:auto":"tiDBTPFa53YMfHiupX3vSRE/ZcCiCjmGt7gDpIpDpwZapeays5Vqqcqb7KiywrDldpTkrrdJBAw2jXcq6ZyhDw"}},"state_key":"@userid:kaer.morhen","type":"m.room.member"}`),
+		// room name
+		[]byte(`{"auth_events":[["$N4us6vqqq3RjvpKd:kaer.morhen",{"sha256":"SylirfgfXFhscZL7p10NmOa1nFFEckiwz0lAideQMIM"}],["$6sUiGPQ0a3tqYGKo:kaer.morhen",{"sha256":"IS4HSMqpqVUGh1Z3qgC99YcaizjCoO4yFhYYe8j53IE"}]],"content":{"name":"My Room Name"},"depth":2,"event_id":"$VC1zZ9YWwuUbSNHD:kaer.morhen","hashes":{"sha256":"bpqTkfLx6KHzWz7/wwpsXnXwJWEGW14aV63ffexzDFg"},"origin":"kaer.morhen","origin_server_ts":0,"prev_events":[["$6sUiGPQ0a3tqYGKo:kaer.morhen",{"sha256":"IS4HSMqpqVUGh1Z3qgC99YcaizjCoO4yFhYYe8j53IE"}]],"prev_state":[],"room_id":"!roomid:kaer.morhen","sender":"@userid:kaer.morhen","signatures":{"kaer.morhen":{"ed25519:auto":"mhJZ3X4bAKrF/T0mtPf1K2Tmls0h6xGY1IPDpJ/SScQBqDlu3HQR2BPa7emqj5bViyLTWVNh+ZCpzx/6STTrAg"}},"state_key":"","type":"m.room.name"}`),
+		// redact room name
+		[]byte(`{"auth_events":[["$N4us6vqqq3RjvpKd:kaer.morhen",{"sha256":"SylirfgfXFhscZL7p10NmOa1nFFEckiwz0lAideQMIM"}],["$6sUiGPQ0a3tqYGKo:kaer.morhen",{"sha256":"IS4HSMqpqVUGh1Z3qgC99YcaizjCoO4yFhYYe8j53IE"}]],"content":{"reason":"Spamming"},"depth":3,"event_id":"$tJI0pE3b8u9UMYpT:kaer.morhen","hashes":{"sha256":"/3TStqa5SQqYaEtl7ajEvSRvu6d12MMKfICUzrBpd2Q"},"origin":"kaer.morhen","origin_server_ts":0,"prev_events":[["$VC1zZ9YWwuUbSNHD:kaer.morhen",{"sha256":"+l8cNa7syvm0EF7CAmQRlYknLEMjivnI4FLhB/TUBEY"}]],"redacts":"$VC1zZ9YWwuUbSNHD:kaer.morhen","room_id":"!roomid:kaer.morhen","sender":"@userid:kaer.morhen","signatures":{"kaer.morhen":{"ed25519:auto":"QBOh+amf0vTJbm6+9VwAcR9uJviBIor2KON0Y7+EyQx5YbUZEzW1HPeJxarLIHBcxMzgOVzjuM+StzjbUgDzAg"}},"type":"m.room.redaction"}`),
+		// message
+		[]byte(`{"auth_events":[["$N4us6vqqq3RjvpKd:kaer.morhen",{"sha256":"SylirfgfXFhscZL7p10NmOa1nFFEckiwz0lAideQMIM"}],["$6sUiGPQ0a3tqYGKo:kaer.morhen",{"sha256":"IS4HSMqpqVUGh1Z3qgC99YcaizjCoO4yFhYYe8j53IE"}]],"content":{"body":"Test Message"},"depth":4,"event_id":"$o8KHsgSIYbJrddnd:kaer.morhen","hashes":{"sha256":"IE/rGVlKOpiGWeIo887g1CK1drYqcWDZhL6THZHkJ1c"},"origin":"kaer.morhen","origin_server_ts":0,"prev_events":[["$tJI0pE3b8u9UMYpT:kaer.morhen",{"sha256":"zvmwyXuDox7jpA16JRH6Fc1zbfQht2tpkBbMTUOi3Jw"}]],"room_id":"!roomid:kaer.morhen","sender":"@userid:kaer.morhen","signatures":{"kaer.morhen":{"ed25519:auto":"/3z+pJjiJXWhwfqIEzmNksvBHCoXTktK/y0rRuWJXw6i1+ygRG/suDCKhFuuz6gPapRmEMPVILi2mJqHHXPKAg"}},"type":"m.room.message"}`),
+		// redact previous message
+		[]byte(`{"auth_events":[["$N4us6vqqq3RjvpKd:kaer.morhen",{"sha256":"SylirfgfXFhscZL7p10NmOa1nFFEckiwz0lAideQMIM"}],["$6sUiGPQ0a3tqYGKo:kaer.morhen",{"sha256":"IS4HSMqpqVUGh1Z3qgC99YcaizjCoO4yFhYYe8j53IE"}]],"content":{"reason":"Spamming more"},"depth":5,"event_id":"$UpsE8belb2gJItJG:kaer.morhen","hashes":{"sha256":"zU8PWJOld/I7OtjdpltFSKC+DMNm2ZyEXAHcprsafD0"},"origin":"kaer.morhen","origin_server_ts":0,"prev_events":[["$o8KHsgSIYbJrddnd:kaer.morhen",{"sha256":"UgjMuCFXH4warIjKuwlRq9zZ6dSJrZWCd+CkqtgLSHM"}]],"redacts":"$o8KHsgSIYbJrddnd:kaer.morhen","room_id":"!roomid:kaer.morhen","sender":"@userid:kaer.morhen","signatures":{"kaer.morhen":{"ed25519:auto":"zxFGr/7aGOzqOEN6zRNrBpFkkMnfGFPbCteYL33wC+PycBPIK+2WRa5qlAR2+lcLiK3HjIzwRYkKNsVFTqvRAw"}},"type":"m.room.redaction"}`),
+	}
+	var redactedOutputs []api.OutputEvent
+	deleteDatabase()
+	_, producer, hevents := mustSendEvents(t, gomatrixserverlib.RoomVersionV1, redactionEvents)
+	defer deleteDatabase()
+	for _, msg := range producer.producedMessages {
+		if msg.Type == api.OutputTypeRedactedEvent {
+			redactedOutputs = append(redactedOutputs, *msg)
+		}
+	}
+	wantRedactedOutputs := []api.OutputEvent{
+		{
+			Type: api.OutputTypeRedactedEvent,
+			RedactedEvent: &api.OutputRedactedEvent{
+				RedactedEventID: hevents[2].EventID(),
+				RedactedBecause: hevents[3],
+			},
+		},
+		{
+			Type: api.OutputTypeRedactedEvent,
+			RedactedEvent: &api.OutputRedactedEvent{
+				RedactedEventID: hevents[4].EventID(),
+				RedactedBecause: hevents[5],
+			},
+		},
+	}
+	t.Logf("redactedOutputs: %+v", redactedOutputs)
+	if len(wantRedactedOutputs) != len(redactedOutputs) {
+		t.Fatalf("Got %d redacted events, want %d", len(redactedOutputs), len(wantRedactedOutputs))
+	}
+	for i := 0; i < len(wantRedactedOutputs); i++ {
+		if !reflect.DeepEqual(*redactedOutputs[i].RedactedEvent, *wantRedactedOutputs[i].RedactedEvent) {
+			t.Errorf("OutputRedactionEvent %d: wrong event got:\n%+v want:\n%+v", i+1, redactedOutputs[i].RedactedEvent, wantRedactedOutputs[i].RedactedEvent)
+		}
+	}
+}

roomserver/storage/interface.go

@@ -63,8 +63,10 @@ type Database interface {
 	SnapshotNIDFromEventID(ctx context.Context, eventID string) (types.StateSnapshotNID, error)
 	// Look up a room version from the room NID.
 	GetRoomVersionForRoomNID(ctx context.Context, roomNID types.RoomNID) (gomatrixserverlib.RoomVersion, error)
-	// Stores a matrix room event in the database
+	// Stores a matrix room event in the database. Returns the room NID, the state snapshot and the redacted event ID if any, or an error.
-	StoreEvent(ctx context.Context, event gomatrixserverlib.Event, txnAndSessionID *api.TransactionID, authEventNIDs []types.EventNID) (types.RoomNID, types.StateAtEvent, error)
+	StoreEvent(
+		ctx context.Context, event gomatrixserverlib.Event, txnAndSessionID *api.TransactionID, authEventNIDs []types.EventNID,
+	) (types.RoomNID, types.StateAtEvent, *gomatrixserverlib.Event, string, error)
 	// Look up the state entries for a list of string event IDs
 	// Returns an error if the there is an error talking to the database
 	// Returns a types.MissingEventError if the event IDs aren't in the database.

roomserver/storage/postgres/redactions_table.go

@@ -41,11 +41,11 @@ const insertRedactionSQL = "" +
 	"INSERT INTO roomserver_redactions (redaction_event_id, redacts_event_id, validated)" +
 	" VALUES ($1, $2, $3)"
 
-const selectRedactedEventSQL = "" +
+const selectRedactionInfoByRedactionEventIDSQL = "" +
 	"SELECT redaction_event_id, redacts_event_id, validated FROM roomserver_redactions" +
 	" WHERE redaction_event_id = $1"
 
-const selectRedactionEventSQL = "" +
+const selectRedactionInfoByEventBeingRedactedSQL = "" +
 	"SELECT redaction_event_id, redacts_event_id, validated FROM roomserver_redactions" +
 	" WHERE redacts_event_id = $1"
 
@@ -53,10 +53,10 @@ const markRedactionValidatedSQL = "" +
 	" UPDATE roomserver_redactions SET validated = $2 WHERE redaction_event_id = $1"
 
 type redactionStatements struct {
-	insertRedactionStmt        *sql.Stmt
+	insertRedactionStmt                         *sql.Stmt
-	selectRedactedEventStmt    *sql.Stmt
+	selectRedactionInfoByRedactionEventIDStmt   *sql.Stmt
-	selectRedactionEventStmt   *sql.Stmt
+	selectRedactionInfoByEventBeingRedactedStmt *sql.Stmt
-	markRedactionValidatedStmt *sql.Stmt
+	markRedactionValidatedStmt                  *sql.Stmt
 }
 
 func NewPostgresRedactionsTable(db *sql.DB) (tables.Redactions, error) {
@@ -68,8 +68,8 @@ func NewPostgresRedactionsTable(db *sql.DB) (tables.Redactions, error) {
 
 	return s, shared.StatementList{
 		{&s.insertRedactionStmt, insertRedactionSQL},
-		{&s.selectRedactedEventStmt, selectRedactedEventSQL},
+		{&s.selectRedactionInfoByRedactionEventIDStmt, selectRedactionInfoByRedactionEventIDSQL},
-		{&s.selectRedactionEventStmt, selectRedactionEventSQL},
+		{&s.selectRedactionInfoByEventBeingRedactedStmt, selectRedactionInfoByEventBeingRedactedSQL},
 		{&s.markRedactionValidatedStmt, markRedactionValidatedSQL},
 	}.Prepare(db)
 }
@@ -82,32 +82,32 @@ func (s *redactionStatements) InsertRedaction(
 	return err
 }
 
-func (s *redactionStatements) SelectRedactedEvent(
+func (s *redactionStatements) SelectRedactionInfoByRedactionEventID(
 	ctx context.Context, txn *sql.Tx, redactionEventID string,
 ) (info *tables.RedactionInfo, err error) {
 	info = &tables.RedactionInfo{}
-	stmt := sqlutil.TxStmt(txn, s.selectRedactedEventStmt)
+	stmt := sqlutil.TxStmt(txn, s.selectRedactionInfoByRedactionEventIDStmt)
 	err = stmt.QueryRowContext(ctx, redactionEventID).Scan(
 		&info.RedactionEventID, &info.RedactsEventID, &info.Validated,
 	)
 	if err == sql.ErrNoRows {
-		err = nil
 		info = nil
+		err = nil
 	}
 	return
 }
 
-func (s *redactionStatements) SelectRedactionEvent(
+func (s *redactionStatements) SelectRedactionInfoByEventBeingRedacted(
-	ctx context.Context, txn *sql.Tx, redactedEventID string,
+	ctx context.Context, txn *sql.Tx, eventID string,
 ) (info *tables.RedactionInfo, err error) {
 	info = &tables.RedactionInfo{}
-	stmt := sqlutil.TxStmt(txn, s.selectRedactionEventStmt)
+	stmt := sqlutil.TxStmt(txn, s.selectRedactionInfoByEventBeingRedactedStmt)
-	err = stmt.QueryRowContext(ctx, redactedEventID).Scan(
+	err = stmt.QueryRowContext(ctx, eventID).Scan(
 		&info.RedactionEventID, &info.RedactsEventID, &info.Validated,
 	)
 	if err == sql.ErrNoRows {
-		err = nil
 		info = nil
+		err = nil
 	}
 	return
 }

roomserver/storage/shared/storage.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"database/sql"
 	"encoding/json"
-	"fmt"
 
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/roomserver/api"
@@ -345,13 +344,15 @@ func (d *Database) GetLatestEventsForUpdate(
 func (d *Database) StoreEvent(
 	ctx context.Context, event gomatrixserverlib.Event,
 	txnAndSessionID *api.TransactionID, authEventNIDs []types.EventNID,
-) (types.RoomNID, types.StateAtEvent, error) {
+) (types.RoomNID, types.StateAtEvent, *gomatrixserverlib.Event, string, error) {
 	var (
 		roomNID          types.RoomNID
 		eventTypeNID     types.EventTypeNID
 		eventStateKeyNID types.EventStateKeyNID
 		eventNID         types.EventNID
 		stateNID         types.StateSnapshotNID
+		redactionEvent   *gomatrixserverlib.Event
+		redactedEventID  string
 		err              error
 	)
 
@@ -419,11 +420,11 @@ func (d *Database) StoreEvent(
 		if err = d.EventJSONTable.InsertEventJSON(ctx, txn, eventNID, event.JSON()); err != nil {
 			return err
 		}
-
+		redactionEvent, redactedEventID, err = d.handleRedactions(ctx, txn, eventNID, event)
-		return d.handleRedactions(ctx, txn, eventNID, event)
+		return err
 	})
 	if err != nil {
-		return 0, types.StateAtEvent{}, err
+		return 0, types.StateAtEvent{}, nil, "", err
 	}
 
 	return roomNID, types.StateAtEvent{
@@ -435,7 +436,7 @@ func (d *Database) StoreEvent(
 			},
 			EventNID: eventNID,
 		},
-	}, nil
+	}, redactionEvent, redactedEventID, nil
 }
 
 func (d *Database) PublishRoom(ctx context.Context, roomID string, publish bool) error {
@@ -531,20 +532,42 @@ func extractRoomVersionFromCreateEvent(event gomatrixserverlib.Event) (
 // When an event is redacted, the redacted event JSON is modified to add an `unsigned.redacted_because` field. We use this field
 // when loading events to determine whether to apply redactions. This keeps the hot-path of reading events quick as we don't need
 // to cross-reference with other tables when loading.
-func (d *Database) handleRedactions(ctx context.Context, txn *sql.Tx, eventNID types.EventNID, event gomatrixserverlib.Event) error {
+//
+// Returns the redaction event and the event ID of the redacted event if this call resulted in a redaction.
+func (d *Database) handleRedactions(
+	ctx context.Context, txn *sql.Tx, eventNID types.EventNID, event gomatrixserverlib.Event,
+) (*gomatrixserverlib.Event, string, error) {
+	var err error
+	isRedactionEvent := event.Type() == gomatrixserverlib.MRoomRedaction && event.StateKey() == nil
+	if isRedactionEvent {
+		// an event which redacts itself should be ignored
+		if event.EventID() == event.Redacts() {
+			return nil, "", nil
+		}
+
+		err = d.RedactionsTable.InsertRedaction(ctx, txn, tables.RedactionInfo{
+			Validated:        false,
+			RedactionEventID: event.EventID(),
+			RedactsEventID:   event.Redacts(),
+		})
+		if err != nil {
+			return nil, "", err
+		}
+	}
+
 	redactionEvent, redactedEvent, validated, err := d.loadRedactionPair(ctx, txn, eventNID, event)
 	if err != nil {
-		return err
+		return nil, "", err
 	}
 	if validated || redactedEvent == nil || redactionEvent == nil {
 		// we've seen this redaction before or there is nothing to redact
-		return nil
+		return nil, "", nil
 	}
 
 	// mark the event as redacted
 	err = redactedEvent.SetUnsignedField("redacted_because", redactionEvent)
 	if err != nil {
-		return err
+		return nil, "", err
 	}
 	if redactionsArePermanent {
 		redactedEvent.Event = redactedEvent.Redact()
@@ -552,82 +575,51 @@ func (d *Database) handleRedactions(ctx context.Context, txn *sql.Tx, eventNID t
 	// overwrite the eventJSON table
 	err = d.EventJSONTable.InsertEventJSON(ctx, txn, redactedEvent.EventNID, redactedEvent.JSON())
 	if err != nil {
-		return err
+		return nil, "", err
 	}
 
-	return d.RedactionsTable.MarkRedactionValidated(ctx, txn, redactionEvent.EventID(), true)
+	return &redactionEvent.Event, redactedEvent.EventID(), d.RedactionsTable.MarkRedactionValidated(ctx, txn, redactionEvent.EventID(), true)
 }
 
 // loadRedactionPair returns both the redaction event and the redacted event, else nil.
-// nolint:gocyclo
 func (d *Database) loadRedactionPair(
 	ctx context.Context, txn *sql.Tx, eventNID types.EventNID, event gomatrixserverlib.Event,
 ) (*types.Event, *types.Event, bool, error) {
 	var redactionEvent, redactedEvent *types.Event
 	var info *tables.RedactionInfo
-	var nids map[string]types.EventNID
-	var evs []types.Event
 	var err error
 	isRedactionEvent := event.Type() == gomatrixserverlib.MRoomRedaction && event.StateKey() == nil
+
+	var eventBeingRedacted string
 	if isRedactionEvent {
+		eventBeingRedacted = event.Redacts()
 		redactionEvent = &types.Event{
 			EventNID: eventNID,
 			Event:    event,
 		}
-		// find the redacted event if one exists
-		info, err = d.RedactionsTable.SelectRedactedEvent(ctx, txn, event.EventID())
-		if err != nil {
-			return nil, nil, false, err
-		}
-		if info == nil {
-			// we don't have the redacted event yet
-			return nil, nil, false, nil
-		}
-		nids, err = d.EventNIDs(ctx, []string{info.RedactsEventID})
-		if err != nil {
-			return nil, nil, false, err
-		}
-		if len(nids) == 0 {
-			return nil, nil, false, fmt.Errorf("redaction: missing event NID being redacted: %+v", info)
-		}
-		evs, err = d.Events(ctx, []types.EventNID{nids[info.RedactsEventID]})
-		if err != nil {
-			return nil, nil, false, err
-		}
-		if len(evs) != 1 {
-			return nil, nil, false, fmt.Errorf("redaction: missing event being redacted: %+v", info)
-		}
-		redactedEvent = &evs[0]
 	} else {
+		eventBeingRedacted = event.EventID() // maybe, we'll see if we have info
 		redactedEvent = &types.Event{
 			EventNID: eventNID,
 			Event:    event,
 		}
-		// find the redaction event if one exists
-		info, err = d.RedactionsTable.SelectRedactionEvent(ctx, txn, event.EventID())
-		if err != nil {
-			return nil, nil, false, err
-		}
-		if info == nil {
-			// this event is not redacted
-			return nil, nil, false, nil
-		}
-		nids, err = d.EventNIDs(ctx, []string{info.RedactionEventID})
-		if err != nil {
-			return nil, nil, false, err
-		}
-		if len(nids) == 0 {
-			return nil, nil, false, fmt.Errorf("redaction: missing redaction event NID: %+v", info)
-		}
-		evs, err = d.Events(ctx, []types.EventNID{nids[info.RedactionEventID]})
-		if err != nil {
-			return nil, nil, false, err
-		}
-		if len(evs) != 1 {
-			return nil, nil, false, fmt.Errorf("redaction: missing redaction event: %+v", info)
-		}
-		redactionEvent = &evs[0]
 	}
+
+	info, err = d.RedactionsTable.SelectRedactionInfoByEventBeingRedacted(ctx, txn, eventBeingRedacted)
+	if err != nil {
+		return nil, nil, false, err
+	}
+	if info == nil {
+		// this event hasn't been redacted or we don't have the redaction for it yet
+		return nil, nil, false, nil
+	}
+
+	if isRedactionEvent {
+		redactedEvent = d.loadEvent(ctx, info.RedactsEventID)
+	} else {
+		redactionEvent = d.loadEvent(ctx, info.RedactionEventID)
+	}
+
 	return redactionEvent, redactedEvent, info.Validated, nil
 }
 
@@ -639,3 +631,22 @@ func (d *Database) applyRedactions(events []types.Event) {
 		}
 	}
 }
+
+// loadEvent loads a single event or returns nil on any problems/missing event
+func (d *Database) loadEvent(ctx context.Context, eventID string) *types.Event {
+	nids, err := d.EventNIDs(ctx, []string{eventID})
+	if err != nil {
+		return nil
+	}
+	if len(nids) == 0 {
+		return nil
+	}
+	evs, err := d.Events(ctx, []types.EventNID{nids[eventID]})
+	if err != nil {
+		return nil
+	}
+	if len(evs) != 1 {
+		return nil
+	}
+	return &evs[0]
+}

roomserver/storage/sqlite3/redactions_table.go

@@ -40,11 +40,11 @@ const insertRedactionSQL = "" +
 	"INSERT INTO roomserver_redactions (redaction_event_id, redacts_event_id, validated)" +
 	" VALUES ($1, $2, $3)"
 
-const selectRedactedEventSQL = "" +
+const selectRedactionInfoByRedactionEventIDSQL = "" +
 	"SELECT redaction_event_id, redacts_event_id, validated FROM roomserver_redactions" +
 	" WHERE redaction_event_id = $1"
 
-const selectRedactionEventSQL = "" +
+const selectRedactionInfoByEventBeingRedactedSQL = "" +
 	"SELECT redaction_event_id, redacts_event_id, validated FROM roomserver_redactions" +
 	" WHERE redacts_event_id = $1"
 
@@ -52,10 +52,10 @@ const markRedactionValidatedSQL = "" +
 	" UPDATE roomserver_redactions SET validated = $2 WHERE redaction_event_id = $1"
 
 type redactionStatements struct {
-	insertRedactionStmt        *sql.Stmt
+	insertRedactionStmt                         *sql.Stmt
-	selectRedactedEventStmt    *sql.Stmt
+	selectRedactionInfoByRedactionEventIDStmt   *sql.Stmt
-	selectRedactionEventStmt   *sql.Stmt
+	selectRedactionInfoByEventBeingRedactedStmt *sql.Stmt
-	markRedactionValidatedStmt *sql.Stmt
+	markRedactionValidatedStmt                  *sql.Stmt
 }
 
 func NewSqliteRedactionsTable(db *sql.DB) (tables.Redactions, error) {
@@ -67,8 +67,8 @@ func NewSqliteRedactionsTable(db *sql.DB) (tables.Redactions, error) {
 
 	return s, shared.StatementList{
 		{&s.insertRedactionStmt, insertRedactionSQL},
-		{&s.selectRedactedEventStmt, selectRedactedEventSQL},
+		{&s.selectRedactionInfoByRedactionEventIDStmt, selectRedactionInfoByRedactionEventIDSQL},
-		{&s.selectRedactionEventStmt, selectRedactionEventSQL},
+		{&s.selectRedactionInfoByEventBeingRedactedStmt, selectRedactionInfoByEventBeingRedactedSQL},
 		{&s.markRedactionValidatedStmt, markRedactionValidatedSQL},
 	}.Prepare(db)
 }
@@ -81,11 +81,11 @@ func (s *redactionStatements) InsertRedaction(
 	return err
 }
 
-func (s *redactionStatements) SelectRedactedEvent(
+func (s *redactionStatements) SelectRedactionInfoByRedactionEventID(
 	ctx context.Context, txn *sql.Tx, redactionEventID string,
 ) (info *tables.RedactionInfo, err error) {
 	info = &tables.RedactionInfo{}
-	stmt := sqlutil.TxStmt(txn, s.selectRedactedEventStmt)
+	stmt := sqlutil.TxStmt(txn, s.selectRedactionInfoByRedactionEventIDStmt)
 	err = stmt.QueryRowContext(ctx, redactionEventID).Scan(
 		&info.RedactionEventID, &info.RedactsEventID, &info.Validated,
 	)
@@ -96,12 +96,12 @@ func (s *redactionStatements) SelectRedactedEvent(
 	return
 }
 
-func (s *redactionStatements) SelectRedactionEvent(
+func (s *redactionStatements) SelectRedactionInfoByEventBeingRedacted(
-	ctx context.Context, txn *sql.Tx, redactedEventID string,
+	ctx context.Context, txn *sql.Tx, eventID string,
 ) (info *tables.RedactionInfo, err error) {
 	info = &tables.RedactionInfo{}
-	stmt := sqlutil.TxStmt(txn, s.selectRedactionEventStmt)
+	stmt := sqlutil.TxStmt(txn, s.selectRedactionInfoByEventBeingRedactedStmt)
-	err = stmt.QueryRowContext(ctx, redactedEventID).Scan(
+	err = stmt.QueryRowContext(ctx, eventID).Scan(
 		&info.RedactionEventID, &info.RedactsEventID, &info.Validated,
 	)
 	if err == sql.ErrNoRows {

roomserver/storage/tables/interface.go

@@ -139,10 +139,10 @@ type RedactionInfo struct {
 
 type Redactions interface {
 	InsertRedaction(ctx context.Context, txn *sql.Tx, info RedactionInfo) error
-	// SelectRedactedEvent returns the redaction info for the given redaction event ID, or nil if there is no match.
+	// SelectRedactionInfoByRedactionEventID returns the redaction info for the given redaction event ID, or nil if there is no match.
-	SelectRedactedEvent(ctx context.Context, txn *sql.Tx, redactionEventID string) (*RedactionInfo, error)
+	SelectRedactionInfoByRedactionEventID(ctx context.Context, txn *sql.Tx, redactionEventID string) (*RedactionInfo, error)
-	// SelectRedactionEvent returns the redaction info for the given redacted event ID, or nil if there is no match.
+	// SelectRedactionInfoByEventBeingRedacted returns the redaction info for the given redacted event ID, or nil if there is no match.
-	SelectRedactionEvent(ctx context.Context, txn *sql.Tx, redactedEventID string) (*RedactionInfo, error)
+	SelectRedactionInfoByEventBeingRedacted(ctx context.Context, txn *sql.Tx, eventID string) (*RedactionInfo, error)
 	// Mark this redaction event as having been validated. This means we have both sides of the redaction and have
 	// successfully redacted the event JSON.
 	MarkRedactionValidated(ctx context.Context, txn *sql.Tx, redactionEventID string, validated bool) error