BREAKING: Remove Partitioned Stream Positions (#2096)

* go mod tidy

* Break complement to check it fails CI

* Remove partitioned stream positions

This was used by the device list stream position. The device list position
now corresponds to the `Offset`, and the partition is always 0, in prep
for removing reliance on Kafka topics for device list changes.

* Linting

* Migrate old style tokens to new style because element-web doesn't soft-logoout on 4xx errors on /sync

14 files changed, 70 insertions, 231 deletions

diff --git a/go.mod b/go.mod
index eb421ce1..e6202f66 100644
--- a/go.mod
+++ b/go.mod
@@ -9,7 +9,7 @@ require (
 	github.com/Arceliar/phony v0.0.0-20210209235338-dde1a8dca979
 	github.com/DATA-DOG/go-sqlmock v1.5.0
 	github.com/HdrHistogram/hdrhistogram-go v1.0.1 // indirect
-	github.com/MFAshby/stdemuxerhook v1.0.0 // indirect
+	github.com/MFAshby/stdemuxerhook v1.0.0
 	github.com/Masterminds/semver/v3 v3.1.1
 	github.com/S7evinK/saramajetstream v0.0.0-20210709110708-de6efc8c4a32
 	github.com/Shopify/sarama v1.29.0
diff --git a/keyserver/api/api.go b/keyserver/api/api.go
index 5a109cc6..eae14ae1 100644
--- a/keyserver/api/api.go
+++ b/keyserver/api/api.go
@@ -224,8 +224,6 @@ type QueryKeysResponse struct {
 }
 
 type QueryKeyChangesRequest struct {
-	// The partition which had key events sent to
-	Partition int32
 	// The offset of the last received key event, or sarama.OffsetOldest if this is from the beginning
 	Offset int64
 	// The inclusive offset where to track key changes up to. Messages with this offset are included in the response.
@@ -236,8 +234,6 @@ type QueryKeyChangesRequest struct {
 type QueryKeyChangesResponse struct {
 	// The set of users who have had their keys change.
 	UserIDs []string
-	// The partition being served - useful if the partition is unknown at request time
-	Partition int32
 	// The latest offset represented in this response.
 	Offset int64
 	// Set if there was a problem handling the request.
diff --git a/keyserver/internal/internal.go b/keyserver/internal/internal.go
index 3e91962e..0140a8f4 100644
--- a/keyserver/internal/internal.go
+++ b/keyserver/internal/internal.go
@@ -59,17 +59,14 @@ func (a *KeyInternalAPI) InputDeviceListUpdate(
 }
 
 func (a *KeyInternalAPI) QueryKeyChanges(ctx context.Context, req *api.QueryKeyChangesRequest, res *api.QueryKeyChangesResponse) {
-	if req.Partition < 0 {
-		req.Partition = a.Producer.DefaultPartition()
-	}
-	userIDs, latest, err := a.DB.KeyChanges(ctx, req.Partition, req.Offset, req.ToOffset)
+	partition := 0
+	userIDs, latest, err := a.DB.KeyChanges(ctx, int32(partition), req.Offset, req.ToOffset)
 	if err != nil {
 		res.Error = &api.KeyError{
 			Err: err.Error(),
 		}
 	}
 	res.Offset = latest
-	res.Partition = req.Partition
 	res.UserIDs = userIDs
 }
 
diff --git a/keyserver/producers/keychange.go b/keyserver/producers/keychange.go
index 782675c2..c5ddf2c1 100644
--- a/keyserver/producers/keychange.go
+++ b/keyserver/producers/keychange.go
@@ -32,15 +32,6 @@ type KeyChange struct {
 	DB       storage.Database
 }
 
-// DefaultPartition returns the default partition this process is sending key changes to.
-// NB: A keyserver MUST send key changes to only 1 partition or else query operations will
-// become inconsistent. Partitions can be sharded (e.g by hash of user ID of key change) but
-// then all keyservers must be queried to calculate the entire set of key changes between
-// two sync tokens.
-func (p *KeyChange) DefaultPartition() int32 {
-	return 0
-}
-
 // ProduceKeyChanges creates new change events for each key
 func (p *KeyChange) ProduceKeyChanges(keys []api.DeviceMessage) error {
 	userToDeviceCount := make(map[string]int)
diff --git a/syncapi/consumers/keychange.go b/syncapi/consumers/keychange.go
index 76b143d8..d63e4832 100644
--- a/syncapi/consumers/keychange.go
+++ b/syncapi/consumers/keychange.go
@@ -38,7 +38,7 @@ type OutputKeyChangeEventConsumer struct {
 	keyChangeConsumer   *internal.ContinualConsumer
 	db                  storage.Database
 	notifier            *notifier.Notifier
-	stream              types.PartitionedStreamProvider
+	stream              types.StreamProvider
 	serverName          gomatrixserverlib.ServerName // our server name
 	rsAPI               roomserverAPI.RoomserverInternalAPI
 	keyAPI              api.KeyInternalAPI
@@ -57,7 +57,7 @@ func NewOutputKeyChangeEventConsumer(
 	rsAPI roomserverAPI.RoomserverInternalAPI,
 	store storage.Database,
 	notifier *notifier.Notifier,
-	stream types.PartitionedStreamProvider,
+	stream types.StreamProvider,
 ) *OutputKeyChangeEventConsumer {
 
 	consumer := internal.ContinualConsumer{
@@ -118,15 +118,15 @@ func (s *OutputKeyChangeEventConsumer) onMessage(msg *sarama.ConsumerMessage) er
 	}
 	switch m.Type {
 	case api.TypeCrossSigningUpdate:
-		return s.onCrossSigningMessage(m, msg.Offset, msg.Partition)
+		return s.onCrossSigningMessage(m, msg.Offset)
 	case api.TypeDeviceKeyUpdate:
 		fallthrough
 	default:
-		return s.onDeviceKeyMessage(m, msg.Offset, msg.Partition)
+		return s.onDeviceKeyMessage(m, msg.Offset)
 	}
 }
 
-func (s *OutputKeyChangeEventConsumer) onDeviceKeyMessage(m api.DeviceMessage, offset int64, partition int32) error {
+func (s *OutputKeyChangeEventConsumer) onDeviceKeyMessage(m api.DeviceMessage, offset int64) error {
 	if m.DeviceKeys == nil {
 		return nil
 	}
@@ -143,10 +143,7 @@ func (s *OutputKeyChangeEventConsumer) onDeviceKeyMessage(m api.DeviceMessage, o
 	}
 	// make sure we get our own key updates too!
 	queryRes.UserIDsToCount[output.UserID] = 1
-	posUpdate := types.LogPosition{
-		Offset:    offset,
-		Partition: partition,
-	}
+	posUpdate := types.StreamPosition(offset)
 
 	s.stream.Advance(posUpdate)
 	for userID := range queryRes.UserIDsToCount {
@@ -156,7 +153,7 @@ func (s *OutputKeyChangeEventConsumer) onDeviceKeyMessage(m api.DeviceMessage, o
 	return nil
 }
 
-func (s *OutputKeyChangeEventConsumer) onCrossSigningMessage(m api.DeviceMessage, offset int64, partition int32) error {
+func (s *OutputKeyChangeEventConsumer) onCrossSigningMessage(m api.DeviceMessage, offset int64) error {
 	output := m.CrossSigningKeyUpdate
 	// work out who we need to notify about the new key
 	var queryRes roomserverAPI.QuerySharedUsersResponse
@@ -170,10 +167,7 @@ func (s *OutputKeyChangeEventConsumer) onCrossSigningMessage(m api.DeviceMessage
 	}
 	// make sure we get our own key updates too!
 	queryRes.UserIDsToCount[output.UserID] = 1
-	posUpdate := types.LogPosition{
-		Offset:    offset,
-		Partition: partition,
-	}
+	posUpdate := types.StreamPosition(offset)
 
 	s.stream.Advance(posUpdate)
 	for userID := range queryRes.UserIDsToCount {
diff --git a/syncapi/internal/keychange.go b/syncapi/internal/keychange.go
index 56a438fb..41efd4a0 100644
--- a/syncapi/internal/keychange.go
+++ b/syncapi/internal/keychange.go
@@ -47,8 +47,8 @@ func DeviceOTKCounts(ctx context.Context, keyAPI keyapi.KeyInternalAPI, userID,
 // be already filled in with join/leave information.
 func DeviceListCatchup(
 	ctx context.Context, keyAPI keyapi.KeyInternalAPI, rsAPI roomserverAPI.RoomserverInternalAPI,
-	userID string, res *types.Response, from, to types.LogPosition,
-) (newPos types.LogPosition, hasNew bool, err error) {
+	userID string, res *types.Response, from, to types.StreamPosition,
+) (newPos types.StreamPosition, hasNew bool, err error) {
 
 	// Track users who we didn't track before but now do by virtue of sharing a room with them, or not.
 	newlyJoinedRooms := joinedRooms(res, userID)
@@ -64,27 +64,18 @@ func DeviceListCatchup(
 	}
 
 	// now also track users who we already share rooms with but who have updated their devices between the two tokens
-
-	var partition int32
-	var offset int64
-	partition = -1
-	offset = sarama.OffsetOldest
-	// Extract partition/offset from sync token
-	// TODO: In a world where keyserver is sharded there will be multiple partitions and hence multiple QueryKeyChanges to make.
-	if !from.IsEmpty() {
-		partition = from.Partition
-		offset = from.Offset
+	offset := sarama.OffsetOldest
+	toOffset := sarama.OffsetNewest
+	if to > 0 && to > from {
+		toOffset = int64(to)
 	}
-	var toOffset int64
-	toOffset = sarama.OffsetNewest
-	if toLog := to; toLog.Partition == partition && toLog.Offset > 0 {
-		toOffset = toLog.Offset
+	if from > 0 {
+		offset = int64(from)
 	}
 	var queryRes keyapi.QueryKeyChangesResponse
 	keyAPI.QueryKeyChanges(ctx, &keyapi.QueryKeyChangesRequest{
-		Partition: partition,
-		Offset:    offset,
-		ToOffset:  toOffset,
+		Offset:   offset,
+		ToOffset: toOffset,
 	}, &queryRes)
 	if queryRes.Error != nil {
 		// don't fail the catchup because we may have got useful information by tracking membership
@@ -95,8 +86,8 @@ func DeviceListCatchup(
 	var sharedUsersMap map[string]int
 	sharedUsersMap, queryRes.UserIDs = filterSharedUsers(ctx, rsAPI, userID, queryRes.UserIDs)
 	util.GetLogger(ctx).Debugf(
-		"QueryKeyChanges request p=%d,off=%d,to=%d response p=%d off=%d uids=%v",
-		partition, offset, toOffset, queryRes.Partition, queryRes.Offset, queryRes.UserIDs,
+		"QueryKeyChanges request off=%d,to=%d response off=%d uids=%v",
+		offset, toOffset, queryRes.Offset, queryRes.UserIDs,
 	)
 	userSet := make(map[string]bool)
 	for _, userID := range res.DeviceLists.Changed {
@@ -125,13 +116,8 @@ func DeviceListCatchup(
 			res.DeviceLists.Left = append(res.DeviceLists.Left, userID)
 		}
 	}
-	// set the new token
-	to = types.LogPosition{
-		Partition: queryRes.Partition,
-		Offset:    queryRes.Offset,
-	}
 
-	return to, hasNew, nil
+	return types.StreamPosition(queryRes.Offset), hasNew, nil
 }
 
 // TrackChangedUsers calculates the values of device_lists.changed|left in the /sync response.
diff --git a/syncapi/internal/keychange_test.go b/syncapi/internal/keychange_test.go
index e52e5556..d9fb9cf8 100644
--- a/syncapi/internal/keychange_test.go
+++ b/syncapi/internal/keychange_test.go
@@ -6,7 +6,6 @@ import (
 	"sort"
 	"testing"
 
-	"github.com/Shopify/sarama"
 	keyapi "github.com/matrix-org/dendrite/keyserver/api"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/syncapi/types"
@@ -16,11 +15,7 @@ import (
 
 var (
 	syncingUser = "@alice:localhost"
-	emptyToken  = types.LogPosition{}
-	newestToken = types.LogPosition{
-		Offset:    sarama.OffsetNewest,
-		Partition: 0,
-	}
+	emptyToken  = types.StreamPosition(0)
 )
 
 type mockKeyAPI struct{}
@@ -186,7 +181,7 @@ func TestKeyChangeCatchupOnJoinShareNewUser(t *testing.T) {
 			"!another:room": {syncingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, newestToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
 	}
@@ -209,7 +204,7 @@ func TestKeyChangeCatchupOnLeaveShareLeftUser(t *testing.T) {
 			"!another:room": {syncingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, newestToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
 	}
@@ -232,7 +227,7 @@ func TestKeyChangeCatchupOnJoinShareNoNewUsers(t *testing.T) {
 			"!another:room": {syncingUser, existingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, newestToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("Catchup returned an error: %s", err)
 	}
@@ -254,7 +249,7 @@ func TestKeyChangeCatchupOnLeaveShareNoUsers(t *testing.T) {
 			"!another:room": {syncingUser, existingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, newestToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
 	}
@@ -313,7 +308,7 @@ func TestKeyChangeCatchupNoNewJoinsButMessages(t *testing.T) {
 			roomID: {syncingUser, existingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, newestToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
 	}
@@ -341,7 +336,7 @@ func TestKeyChangeCatchupChangeAndLeft(t *testing.T) {
 			"!another:room": {syncingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, newestToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("Catchup returned an error: %s", err)
 	}
@@ -427,7 +422,7 @@ func TestKeyChangeCatchupChangeAndLeftSameRoom(t *testing.T) {
 		},
 	}
 	_, hasNew, err := DeviceListCatchup(
-		context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, newestToken,
+		context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken,
 	)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
diff --git a/syncapi/streams/stream_devicelist.go b/syncapi/streams/stream_devicelist.go
index 9ea9d088..6ff8a7fd 100644
--- a/syncapi/streams/stream_devicelist.go
+++ b/syncapi/streams/stream_devicelist.go
@@ -10,7 +10,7 @@ import (
 )
 
 type DeviceListStreamProvider struct {
-	PartitionedStreamProvider
+	StreamProvider
 	rsAPI  api.RoomserverInternalAPI
 	keyAPI keyapi.KeyInternalAPI
 }
@@ -18,15 +18,15 @@ type DeviceListStreamProvider struct {
 func (p *DeviceListStreamProvider) CompleteSync(
 	ctx context.Context,
 	req *types.SyncRequest,
-) types.LogPosition {
+) types.StreamPosition {
 	return p.LatestPosition(ctx)
 }
 
 func (p *DeviceListStreamProvider) IncrementalSync(
 	ctx context.Context,
 	req *types.SyncRequest,
-	from, to types.LogPosition,
-) types.LogPosition {
+	from, to types.StreamPosition,
+) types.StreamPosition {
 	var err error
 	to, _, err = internal.DeviceListCatchup(context.Background(), p.keyAPI, p.rsAPI, req.Device.UserID, req.Response, from, to)
 	if err != nil {
diff --git a/syncapi/streams/streams.go b/syncapi/streams/streams.go
index ba4118df..6b02c75e 100644
--- a/syncapi/streams/streams.go
+++ b/syncapi/streams/streams.go
@@ -18,7 +18,7 @@ type Streams struct {
 	InviteStreamProvider       types.StreamProvider
 	SendToDeviceStreamProvider types.StreamProvider
 	AccountDataStreamProvider  types.StreamProvider
-	DeviceListStreamProvider   types.PartitionedStreamProvider
+	DeviceListStreamProvider   types.StreamProvider
 }
 
 func NewSyncStreamProviders(
@@ -48,9 +48,9 @@ func NewSyncStreamProviders(
 			userAPI:        userAPI,
 		},
 		DeviceListStreamProvider: &DeviceListStreamProvider{
-			PartitionedStreamProvider: PartitionedStreamProvider{DB: d},
-			rsAPI:                     rsAPI,
-			keyAPI:                    keyAPI,
+			StreamProvider: StreamProvider{DB: d},
+			rsAPI:          rsAPI,
+			keyAPI:         keyAPI,
 		},
 	}
 
diff --git a/syncapi/streams/template_pstream.go b/syncapi/streams/template_pstream.go
deleted file mode 100644
index 265e22a2..00000000
--- a/syncapi/streams/template_pstream.go
+++ /dev/null
@@ -1,38 +0,0 @@
-package streams
-
-import (
-	"context"
-	"sync"
-
-	"github.com/matrix-org/dendrite/syncapi/storage"
-	"github.com/matrix-org/dendrite/syncapi/types"
-)
-
-type PartitionedStreamProvider struct {
-	DB          storage.Database
-	latest      types.LogPosition
-	latestMutex sync.RWMutex
-}
-
-func (p *PartitionedStreamProvider) Setup() {
-}
-
-func (p *PartitionedStreamProvider) Advance(
-	latest types.LogPosition,
-) {
-	p.latestMutex.Lock()
-	defer p.latestMutex.Unlock()
-
-	if latest.IsAfter(&p.latest) {
-		p.latest = latest
-	}
-}
-
-func (p *PartitionedStreamProvider) LatestPosition(
-	ctx context.Context,
-) types.LogPosition {
-	p.latestMutex.RLock()
-	defer p.latestMutex.RUnlock()
-
-	return p.latest
-}
diff --git a/syncapi/sync/requestpool.go b/syncapi/sync/requestpool.go
index a4573610..ca35951a 100644
--- a/syncapi/sync/requestpool.go
+++ b/syncapi/sync/requestpool.go
@@ -140,6 +140,12 @@ func (rp *RequestPool) OnIncomingSyncRequest(req *http.Request, device *userapi.
 	// Extract values from request
 	syncReq, err := newSyncRequest(req, *device, rp.db)
 	if err != nil {
+		if err == types.ErrMalformedSyncToken {
+			return util.JSONResponse{
+				Code: http.StatusBadRequest,
+				JSON: jsonerror.InvalidArgumentValue(err.Error()),
+			}
+		}
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
 			JSON: jsonerror.Unknown(err.Error()),
diff --git a/syncapi/types/provider.go b/syncapi/types/provider.go
index 93ed1266..f6185fcb 100644
--- a/syncapi/types/provider.go
+++ b/syncapi/types/provider.go
@@ -42,11 +42,3 @@ type StreamProvider interface {
 	// LatestPosition returns the latest stream position for this stream.
 	LatestPosition(ctx context.Context) StreamPosition
 }
-
-type PartitionedStreamProvider interface {
-	Setup()
-	Advance(latest LogPosition)
-	CompleteSync(ctx context.Context, req *SyncRequest) LogPosition
-	IncrementalSync(ctx context.Context, req *SyncRequest, from, to LogPosition) LogPosition
-	LatestPosition(ctx context.Context) LogPosition
-}
diff --git a/syncapi/types/types.go b/syncapi/types/types.go
index 44e718b3..68c308d8 100644
--- a/syncapi/types/types.go
+++ b/syncapi/types/types.go
@@ -16,6 +16,7 @@ package types
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -26,13 +27,10 @@ import (
 )
 
 var (
-	// ErrInvalidSyncTokenType is returned when an attempt at creating a
-	// new instance of SyncToken with an invalid type (i.e. neither "s"
-	// nor "t").
-	ErrInvalidSyncTokenType = fmt.Errorf("sync token has an unknown prefix (should be either s or t)")
-	// ErrInvalidSyncTokenLen is returned when the pagination token is an
-	// invalid length
-	ErrInvalidSyncTokenLen = fmt.Errorf("sync token has an invalid length")
+	// This error is returned when parsing sync tokens if the token is invalid. Callers can use this
+	// error to detect whether to 400 or 401 the client. It is recommended to 401 them to force a
+	// logout.
+	ErrMalformedSyncToken = errors.New("malformed sync token")
 )
 
 type StateDelta struct {
@@ -47,27 +45,6 @@ type StateDelta struct {
 // StreamPosition represents the offset in the sync stream a client is at.
 type StreamPosition int64
 
-// LogPosition represents the offset in a Kafka log a client is at.
-type LogPosition struct {
-	Partition int32
-	Offset    int64
-}
-
-func (p *LogPosition) IsEmpty() bool {
-	return p.Offset == 0
-}
-
-// IsAfter returns true if this position is after `lp`.
-func (p *LogPosition) IsAfter(lp *LogPosition) bool {
-	if lp == nil {
-		return false
-	}
-	if p.Partition != lp.Partition {
-		return false
-	}
-	return p.Offset > lp.Offset
-}
-
 // StreamEvent is the same as gomatrixserverlib.Event but also has the PDU stream position for this event.
 type StreamEvent struct {
 	*gomatrixserverlib.HeaderedEvent
@@ -124,7 +101,7 @@ type StreamingToken struct {
 	SendToDevicePosition StreamPosition
 	InvitePosition       StreamPosition
 	AccountDataPosition  StreamPosition
-	DeviceListPosition   LogPosition
+	DeviceListPosition   StreamPosition
 }
 
 // This will be used as a fallback by json.Marshal.
@@ -140,14 +117,11 @@ func (s *StreamingToken) UnmarshalText(text []byte) (err error) {
 
 func (t StreamingToken) String() string {
 	posStr := fmt.Sprintf(
-		"s%d_%d_%d_%d_%d_%d",
+		"s%d_%d_%d_%d_%d_%d_%d",
 		t.PDUPosition, t.TypingPosition,
 		t.ReceiptPosition, t.SendToDevicePosition,
-		t.InvitePosition, t.AccountDataPosition,
+		t.InvitePosition, t.AccountDataPosition, t.DeviceListPosition,
 	)
-	if dl := t.DeviceListPosition; !dl.IsEmpty() {
-		posStr += fmt.Sprintf(".dl-%d-%d", dl.Partition, dl.Offset)
-	}
 	return posStr
 }
 
@@ -166,14 +140,14 @@ func (t *StreamingToken) IsAfter(other StreamingToken) bool {
 		return true
 	case t.AccountDataPosition > other.AccountDataPosition:
 		return true
-	case t.DeviceListPosition.IsAfter(&other.DeviceListPosition):
+	case t.DeviceListPosition > other.DeviceListPosition:
 		return true
 	}
 	return false
 }
 
 func (t *StreamingToken) IsEmpty() bool {
-	return t == nil || t.PDUPosition+t.TypingPosition+t.ReceiptPosition+t.SendToDevicePosition+t.InvitePosition+t.AccountDataPosition == 0 && t.DeviceListPosition.IsEmpty()
+	return t == nil || t.PDUPosition+t.TypingPosition+t.ReceiptPosition+t.SendToDevicePosition+t.InvitePosition+t.AccountDataPosition+t.DeviceListPosition == 0
 }
 
 // WithUpdates returns a copy of the StreamingToken with updates applied from another StreamingToken.
@@ -208,7 +182,7 @@ func (t *StreamingToken) ApplyUpdates(other StreamingToken) {
 	if other.AccountDataPosition > t.AccountDataPosition {
 		t.AccountDataPosition = other.AccountDataPosition
 	}
-	if other.DeviceListPosition.IsAfter(&t.DeviceListPosition) {
+	if other.DeviceListPosition > t.DeviceListPosition {
 		t.DeviceListPosition = other.DeviceListPosition
 	}
 }
@@ -292,16 +266,18 @@ func NewTopologyTokenFromString(tok string) (token TopologyToken, err error) {
 
 func NewStreamTokenFromString(tok string) (token StreamingToken, err error) {
 	if len(tok) < 1 {
-		err = fmt.Errorf("empty stream token")
+		err = ErrMalformedSyncToken
 		return
 	}
 	if tok[0] != SyncTokenTypeStream[0] {
-		err = fmt.Errorf("stream token must start with 's'")
+		err = ErrMalformedSyncToken
 		return
 	}
-	categories := strings.Split(tok[1:], ".")
-	parts := strings.Split(categories[0], "_")
-	var positions [6]StreamPosition
+	// Migration: Remove everything after and including '.' - we previously had tokens like:
+	// s478_0_0_0_0_13.dl-0-2 but we have now removed partitioned stream positions
+	tok = strings.Split(tok, ".")[0]
+	parts := strings.Split(tok[1:], "_")
+	var positions [7]StreamPosition
 	for i, p := range parts {
 		if i > len(positions) {
 			break
@@ -309,6 +285,7 @@ func NewStreamTokenFromString(tok string) (token StreamingToken, err error) {
 		var pos int
 		pos, err = strconv.Atoi(p)
 		if err != nil {
+			err = ErrMalformedSyncToken
 			return
 		}
 		positions[i] = StreamPosition(pos)
@@ -320,31 +297,7 @@ func NewStreamTokenFromString(tok string) (token StreamingToken, err error) {
 		SendToDevicePosition: positions[3],
 		InvitePosition:       positions[4],
 		AccountDataPosition:  positions[5],
-	}
-	// dl-0-1234
-	// $log_name-$partition-$offset
-	for _, logStr := range categories[1:] {
-		segments := strings.Split(logStr, "-")
-		if len(segments) != 3 {
-			err = fmt.Errorf("invalid log position %q", logStr)
-			return
-		}
-		switch segments[0] {
-		case "dl":
-			// Device list syncing
-			var partition, offset int
-			if partition, err = strconv.Atoi(segments[1]); err != nil {
-				return
-			}
-			if offset, err = strconv.Atoi(segments[2]); err != nil {
-				return
-			}
-			token.DeviceListPosition.Partition = int32(partition)
-			token.DeviceListPosition.Offset = int64(offset)
-		default:
-			err = fmt.Errorf("unrecognised token type %q", segments[0])
-			return
-		}
+		DeviceListPosition:   positions[6],
 	}
 	return token, nil
 }
diff --git a/syncapi/types/types_test.go b/syncapi/types/types_test.go
index 3e577788..cda178b3 100644
--- a/syncapi/types/types_test.go
+++ b/syncapi/types/types_test.go
@@ -2,50 +2,17 @@ package types
 
 import (
 	"encoding/json"
-	"reflect"
 	"testing"
 
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
-func TestNewSyncTokenWithLogs(t *testing.T) {
-	tests := map[string]*StreamingToken{
-		"s4_0_0_0_0_0": {
-			PDUPosition: 4,
-		},
-		"s4_0_0_0_0_0.dl-0-123": {
-			PDUPosition: 4,
-			DeviceListPosition: LogPosition{
-				Partition: 0,
-				Offset:    123,
-			},
-		},
-	}
-	for tok, want := range tests {
-		got, err := NewStreamTokenFromString(tok)
-		if err != nil {
-			if want == nil {
-				continue // error expected
-			}
-			t.Errorf("%s errored: %s", tok, err)
-			continue
-		}
-		if !reflect.DeepEqual(got, *want) {
-			t.Errorf("%s mismatch: got %v want %v", tok, got, want)
-		}
-		gotStr := got.String()
-		if gotStr != tok {
-			t.Errorf("%s reserialisation mismatch: got %s want %s", tok, gotStr, tok)
-		}
-	}
-}
-
 func TestSyncTokens(t *testing.T) {
 	shouldPass := map[string]string{
-		"s4_0_0_0_0_0":        StreamingToken{4, 0, 0, 0, 0, 0, LogPosition{}}.String(),
-		"s3_1_0_0_0_0.dl-1-2": StreamingToken{3, 1, 0, 0, 0, 0, LogPosition{1, 2}}.String(),
-		"s3_1_2_3_5_0":        StreamingToken{3, 1, 2, 3, 5, 0, LogPosition{}}.String(),
-		"t3_1":                TopologyToken{3, 1}.String(),
+		"s4_0_0_0_0_0_0": StreamingToken{4, 0, 0, 0, 0, 0, 0}.String(),
+		"s3_1_0_0_0_0_2": StreamingToken{3, 1, 0, 0, 0, 0, 2}.String(),
+		"s3_1_2_3_5_0_0": StreamingToken{3, 1, 2, 3, 5, 0, 0}.String(),
+		"t3_1":           TopologyToken{3, 1}.String(),
 	}
 
 	for a, b := range shouldPass {