Fix `m.receipt`s causing notifications (#2893)

Fixes https://github.com/matrix-org/dendrite/issues/2353

3 files changed, 108 insertions, 2 deletions

diff --git a/syncapi/streams/stream_receipt.go b/syncapi/streams/stream_receipt.go
index 97781507..16a81e83 100644
--- a/syncapi/streams/stream_receipt.go
+++ b/syncapi/streams/stream_receipt.go
@@ -87,8 +87,7 @@ func (p *ReceiptStreamProvider) IncrementalSync(
 		}
 
 		ev := gomatrixserverlib.ClientEvent{
-			Type:   gomatrixserverlib.MReceipt,
-			RoomID: roomID,
+			Type: gomatrixserverlib.MReceipt,
 		}
 		content := make(map[string]ReceiptMRead)
 		for _, receipt := range receipts {
diff --git a/syncapi/types/types.go b/syncapi/types/types.go
index 295187ac..9fbadc06 100644
--- a/syncapi/types/types.go
+++ b/syncapi/types/types.go
@@ -480,6 +480,13 @@ func (jr JoinResponse) MarshalJSON() ([]byte, error) {
 	if jr.Ephemeral != nil && len(jr.Ephemeral.Events) == 0 {
 		a.Ephemeral = nil
 	}
+	if jr.Ephemeral != nil {
+		// Remove the room_id from EDUs, as this seems to cause Element Web
+		// to trigger notifications - https://github.com/vector-im/element-web/issues/17263
+		for i := range jr.Ephemeral.Events {
+			jr.Ephemeral.Events[i].RoomID = ""
+		}
+	}
 	if jr.AccountData != nil && len(jr.AccountData.Events) == 0 {
 		a.AccountData = nil
 	}
diff --git a/syncapi/types/types_test.go b/syncapi/types/types_test.go
index 19fcfc15..74246d96 100644
--- a/syncapi/types/types_test.go
+++ b/syncapi/types/types_test.go
@@ -2,6 +2,7 @@ package types
 
 import (
 	"encoding/json"
+	"reflect"
 	"testing"
 
 	"github.com/matrix-org/gomatrixserverlib"
@@ -63,3 +64,102 @@ func TestNewInviteResponse(t *testing.T) {
 		t.Fatalf("Invite response didn't contain correct info")
 	}
 }
+
+func TestJoinResponse_MarshalJSON(t *testing.T) {
+	type fields struct {
+		Summary             *Summary
+		State               *ClientEvents
+		Timeline            *Timeline
+		Ephemeral           *ClientEvents
+		AccountData         *ClientEvents
+		UnreadNotifications *UnreadNotifications
+	}
+	tests := []struct {
+		name    string
+		fields  fields
+		want    []byte
+		wantErr bool
+	}{
+		{
+			name: "empty state is removed",
+			fields: fields{
+				State: &ClientEvents{},
+			},
+			want: []byte("{}"),
+		},
+		{
+			name: "empty accountdata is removed",
+			fields: fields{
+				AccountData: &ClientEvents{},
+			},
+			want: []byte("{}"),
+		},
+		{
+			name: "empty ephemeral is removed",
+			fields: fields{
+				Ephemeral: &ClientEvents{},
+			},
+			want: []byte("{}"),
+		},
+		{
+			name: "empty timeline is removed",
+			fields: fields{
+				Timeline: &Timeline{},
+			},
+			want: []byte("{}"),
+		},
+		{
+			name: "empty summary is removed",
+			fields: fields{
+				Summary: &Summary{},
+			},
+			want: []byte("{}"),
+		},
+		{
+			name: "unread notifications are removed, if everything else is empty",
+			fields: fields{
+				UnreadNotifications: &UnreadNotifications{},
+			},
+			want: []byte("{}"),
+		},
+		{
+			name: "unread notifications are NOT removed, if state is set",
+			fields: fields{
+				State:               &ClientEvents{Events: []gomatrixserverlib.ClientEvent{{Content: []byte("{}")}}},
+				UnreadNotifications: &UnreadNotifications{NotificationCount: 1},
+			},
+			want: []byte(`{"state":{"events":[{"content":{},"type":""}]},"unread_notifications":{"highlight_count":0,"notification_count":1}}`),
+		},
+		{
+			name: "roomID is removed from EDUs",
+			fields: fields{
+				Ephemeral: &ClientEvents{
+					Events: []gomatrixserverlib.ClientEvent{
+						{RoomID: "!someRandomRoomID:test", Content: []byte("{}")},
+					},
+				},
+			},
+			want: []byte(`{"ephemeral":{"events":[{"content":{},"type":""}]}}`),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			jr := JoinResponse{
+				Summary:             tt.fields.Summary,
+				State:               tt.fields.State,
+				Timeline:            tt.fields.Timeline,
+				Ephemeral:           tt.fields.Ephemeral,
+				AccountData:         tt.fields.AccountData,
+				UnreadNotifications: tt.fields.UnreadNotifications,
+			}
+			got, err := jr.MarshalJSON()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("MarshalJSON() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("MarshalJSON() got = %v, want %v", string(got), string(tt.want))
+			}
+		})
+	}
+}