Federation for v3/v4 rooms (#954)

* Update gomatrixserverlib

* Default to room version 4

* Update gomatrixserverlib

* Limit prev_events and auth_events

* Fix auth_events, prev_events

* Fix linter issues

* Update gomatrixserverlib

* Fix getState

* Update sytest-whitelist

* Squashed commit of the following:

commit 067b875063
Author: Neil Alexander <neilalexander@users.noreply.github.com>
Date:   Fri Apr 3 14:29:06 2020 +0100

    Invites v2 endpoint (#952)

    * Start converting v1 invite endpoint to v2

    * Update gomatrixserverlib

    * Early federationsender code for sending invites

    * Sending invites sorta happens now

    * Populate invite request with stripped state

    * Remodel a bit, don't reflect received invites

    * Handle invite_room_state

    * Handle room versions a bit better

    * Update gomatrixserverlib

    * Tweak order in destinationQueue.next

    * Revert check in processMessage

    * Tweak federation sender destination queue code a bit

    * Add comments

commit 955244c092
Author: Ben B <benne@klimlive.de>
Date:   Fri Apr 3 12:40:50 2020 +0200

    use custom http client instead of the http DefaultClient (#823)

    This commit replaces the default client from the http lib with a custom one.
    The previously used default client doesn't come with a timeout. This could cause
    unwanted locks.
    That solution chosen here creates a http client in the base component dendrite
    with a constant timeout of 30 seconds. If it should be necessary to overwrite
    this, we could include the timeout in the dendrite configuration.
    Here it would be a good idea to extend the type "Address" by a timeout and
    create an http client for each service.

    Closes #820

    Signed-off-by: Benedikt Bongartz <benne@klimlive.de>

    Co-authored-by: Kegsay <kegan@matrix.org>

* Update sytest-whitelist, sytest-blacklist

* Update go.mod/go.sum

* Add some error wrapping for debug

* Add a NOTSPEC to common/events.go

* Perform state resolution at send_join

* Set default room version to v2 again

* Tweak GetCapabilities

* Add comments to ResolveConflictsAdhoc

* Update sytest-blacklist

* go mod tidy

* Update sytest-whitelist, sytest-blacklist

* Update versions

* Updates from review comments

* Update sytest-blacklist, sytest-whitelist

* Check room versions compatible at make_join, add some comments, update gomatrixserverlib, other tweaks

* Set default room version back to v2

* Update gomatrixserverlib, sytest-whitelist

clientapi/routing/capabilities.go

@@ -29,7 +29,7 @@ func GetCapabilities(
 	req *http.Request, queryAPI roomserverAPI.RoomserverQueryAPI,
 ) util.JSONResponse {
 	roomVersionsQueryReq := roomserverAPI.QueryRoomVersionCapabilitiesRequest{}
-	var roomVersionsQueryRes roomserverAPI.QueryRoomVersionCapabilitiesResponse
+	roomVersionsQueryRes := roomserverAPI.QueryRoomVersionCapabilitiesResponse{}
 	if err := queryAPI.QueryRoomVersionCapabilities(
 		req.Context(),
 		&roomVersionsQueryReq,

clientapi/routing/joinroom.go

@@ -242,6 +242,9 @@ func (r joinRoomReq) joinRoomUsingServers(
 	queryRes := roomserverAPI.QueryLatestEventsAndStateResponse{}
 	event, err := common.BuildEvent(r.req.Context(), &eb, r.cfg, r.evTime, r.queryAPI, &queryRes)
 	if err == nil {
+		// If we have successfully built an event at this point then we can
+		// assert that the room is a local room, as BuildEvent was able to
+		// add prev_events etc successfully.
 		if _, err = r.producer.SendEvents(
 			r.req.Context(),
 			[]gomatrixserverlib.HeaderedEvent{
@@ -260,6 +263,10 @@ func (r joinRoomReq) joinRoomUsingServers(
 			}{roomID},
 		}
 	}
+
+	// Otherwise, if we've reached here, then we haven't been able to populate
+	// prev_events etc for the room, therefore the room is probably federated.
+
 	// TODO: This needs to be re-thought, as in the case of an invite, the room
 	// will exist in the database in roomserver_rooms but won't have any state
 	// events, therefore this below check fails.
@@ -323,14 +330,14 @@ func (r joinRoomReq) joinRoomUsingServer(roomID string, server gomatrixserverlib
 	respMakeJoin, err := r.federation.MakeJoin(r.req.Context(), server, roomID, r.userID, supportedVersions)
 	if err != nil {
 		// TODO: Check if the user was not allowed to join the room.
-		return nil, err
+		return nil, fmt.Errorf("r.federation.MakeJoin: %w", err)
 	}
 
 	// Set all the fields to be what they should be, this should be a no-op
 	// but it's possible that the remote server returned us something "odd"
 	err = r.writeToBuilder(&respMakeJoin.JoinEvent, roomID)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("r.writeToBuilder: %w", err)
 	}
 
 	if respMakeJoin.RoomVersion == "" {
@@ -350,18 +357,16 @@ func (r joinRoomReq) joinRoomUsingServer(roomID string, server gomatrixserverlib
 		r.cfg.Matrix.PrivateKey, respMakeJoin.RoomVersion,
 	)
 	if err != nil {
-		util.GetLogger(r.req.Context()).WithError(err).Error("respMakeJoin.JoinEvent.Build failed")
+		return nil, fmt.Errorf("respMakeJoin.JoinEvent.Build: %w", err)
-		res := jsonerror.InternalServerError()
-		return &res, nil
 	}
 
 	respSendJoin, err := r.federation.SendJoin(r.req.Context(), server, event, respMakeJoin.RoomVersion)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("r.federation.SendJoin: %w", err)
 	}
 
 	if err = respSendJoin.Check(r.req.Context(), r.keyRing, event); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("respSendJoin: %w", err)
 	}
 
 	if err = r.producer.SendEventWithState(
@@ -369,9 +374,7 @@ func (r joinRoomReq) joinRoomUsingServer(roomID string, server gomatrixserverlib
 		gomatrixserverlib.RespState(respSendJoin.RespState),
 		event.Headered(respMakeJoin.RoomVersion),
 	); err != nil {
-		util.GetLogger(r.req.Context()).WithError(err).Error("gomatrixserverlib.RespState failed")
+		return nil, fmt.Errorf("r.producer.SendEventWithState: %w", err)
-		res := jsonerror.InternalServerError()
-		return &res, nil
 	}
 
 	return &util.JSONResponse{

common/events.go

@@ -17,6 +17,7 @@ package common
 import (
 	"context"
 	"errors"
+	"fmt"
 	"time"
 
 	"github.com/matrix-org/dendrite/common/config"
@@ -46,6 +47,7 @@ func BuildEvent(
 
 	err := AddPrevEventsToEvent(ctx, builder, queryAPI, queryRes)
 	if err != nil {
+		// This can pass through a ErrRoomNoExists to the caller
 		return nil, err
 	}
 
@@ -68,7 +70,7 @@ func AddPrevEventsToEvent(
 ) error {
 	eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
 	if err != nil {
-		return err
+		return fmt.Errorf("gomatrixserverlib.StateNeededForEventBuilder: %w", err)
 	}
 
 	// Ask the roomserver for information about this room
@@ -77,7 +79,7 @@ func AddPrevEventsToEvent(
 		StateToFetch: eventsNeeded.Tuples(),
 	}
 	if err = queryAPI.QueryLatestEventsAndState(ctx, &queryReq, queryRes); err != nil {
-		return err
+		return fmt.Errorf("queryAPI.QueryLatestEventsAndState: %w", err)
 	}
 
 	if !queryRes.RoomExists {
@@ -86,7 +88,7 @@ func AddPrevEventsToEvent(
 
 	eventFormat, err := queryRes.RoomVersion.EventFormat()
 	if err != nil {
-		return err
+		return fmt.Errorf("queryRes.RoomVersion.EventFormat: %w", err)
 	}
 
 	builder.Depth = queryRes.Depth
@@ -96,26 +98,26 @@ func AddPrevEventsToEvent(
 	for i := range queryRes.StateEvents {
 		err = authEvents.AddEvent(&queryRes.StateEvents[i].Event)
 		if err != nil {
-			return err
+			return fmt.Errorf("authEvents.AddEvent: %w", err)
 		}
 	}
 
 	refs, err := eventsNeeded.AuthEventReferences(&authEvents)
 	if err != nil {
-		return err
+		return fmt.Errorf("eventsNeeded.AuthEventReferences: %w", err)
 	}
 
+	truncAuth, truncPrev := truncateAuthAndPrevEvents(refs, queryRes.LatestEvents)
 	switch eventFormat {
 	case gomatrixserverlib.EventFormatV1:
-		builder.AuthEvents = refs
+		builder.AuthEvents = truncAuth
-		builder.PrevEvents = queryRes.LatestEvents
+		builder.PrevEvents = truncPrev
 	case gomatrixserverlib.EventFormatV2:
-		v2AuthRefs := []string{}
+		v2AuthRefs, v2PrevRefs := []string{}, []string{}
-		v2PrevRefs := []string{}
+		for _, ref := range truncAuth {
-		for _, ref := range refs {
 			v2AuthRefs = append(v2AuthRefs, ref.EventID)
 		}
-		for _, ref := range queryRes.LatestEvents {
+		for _, ref := range truncPrev {
 			v2PrevRefs = append(v2PrevRefs, ref.EventID)
 		}
 		builder.AuthEvents = v2AuthRefs
@@ -124,3 +126,21 @@ func AddPrevEventsToEvent(
 
 	return nil
 }
+
+// truncateAuthAndPrevEvents limits the number of events we add into
+// an event as prev_events or auth_events.
+// NOTSPEC: The limits here feel a bit arbitrary but they are currently
+// here because of https://github.com/matrix-org/matrix-doc/issues/2307
+// and because Synapse will just drop events that don't comply.
+func truncateAuthAndPrevEvents(auth, prev []gomatrixserverlib.EventReference) (
+	truncAuth, truncPrev []gomatrixserverlib.EventReference,
+) {
+	truncAuth, truncPrev = auth, prev
+	if len(truncAuth) > 10 {
+		truncAuth = truncAuth[:10]
+	}
+	if len(truncPrev) > 20 {
+		truncPrev = truncPrev[:20]
+	}
+	return
+}

federationapi/routing/join.go

@@ -15,6 +15,7 @@
 package routing
 
 import (
+	"fmt"
 	"net/http"
 	"time"
 
@@ -34,6 +35,7 @@ func MakeJoin(
 	cfg *config.Dendrite,
 	query api.RoomserverQueryAPI,
 	roomID, userID string,
+	remoteVersions []gomatrixserverlib.RoomVersion,
 ) util.JSONResponse {
 	verReq := api.QueryRoomVersionForRoomRequest{RoomID: roomID}
 	verRes := api.QueryRoomVersionForRoomResponse{}
@@ -44,6 +46,27 @@ func MakeJoin(
 		}
 	}
 
+	// Check that the room that the remote side is trying to join is actually
+	// one of the room versions that they listed in their supported ?ver= in
+	// the make_join URL.
+	// https://matrix.org/docs/spec/server_server/r0.1.3#get-matrix-federation-v1-make-join-roomid-userid
+	remoteSupportsVersion := false
+	for _, v := range remoteVersions {
+		if v == verRes.RoomVersion {
+			remoteSupportsVersion = true
+			break
+		}
+	}
+	// If it isn't, stop trying to join the room.
+	if !remoteSupportsVersion {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.UnsupportedRoomVersion(
+				fmt.Sprintf("Joining server does not support room version %s", verRes.RoomVersion),
+			),
+		}
+	}
+
 	_, domain, err := gomatrixserverlib.SplitID('@', userID)
 	if err != nil {
 		return util.JSONResponse{
@@ -140,7 +163,12 @@ func SendJoin(
 	if event.RoomID() != roomID {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
-			JSON: jsonerror.BadJSON("The room ID in the request path must match the room ID in the join event JSON"),
+			JSON: jsonerror.BadJSON(
+				fmt.Sprintf(
+					"The room ID in the request path (%q) must match the room ID in the join event JSON (%q)",
+					roomID, event.RoomID(),
+				),
+			),
 		}
 	}
 
@@ -148,7 +176,12 @@ func SendJoin(
 	if event.EventID() != eventID {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
-			JSON: jsonerror.BadJSON("The event ID in the request path must match the event ID in the join event JSON"),
+			JSON: jsonerror.BadJSON(
+				fmt.Sprintf(
+					"The event ID in the request path (%q) must match the event ID in the join event JSON (%q)",
+					eventID, event.EventID(),
+				),
+			),
 		}
 	}
 
@@ -186,6 +219,7 @@ func SendJoin(
 		PrevEventIDs: event.PrevEventIDs(),
 		AuthEventIDs: event.AuthEventIDs(),
 		RoomID:       roomID,
+		ResolveState: true,
 	}, &stateAndAuthChainResponse)
 	if err != nil {
 		util.GetLogger(httpReq.Context()).WithError(err).Error("query.QueryStateAndAuthChain failed")

federationapi/routing/routing.go

@@ -198,7 +198,7 @@ func Setup(
 		},
 	)).Methods(http.MethodGet)
 
-	v1fedmux.Handle("/make_join/{roomID}/{userID}", common.MakeFedAPI(
+	v1fedmux.Handle("/make_join/{roomID}/{eventID}", common.MakeFedAPI(
 		"federation_make_join", cfg.Matrix.ServerName, keys,
 		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
 			vars, err := common.URLDecodeMapValues(mux.Vars(httpReq))
@@ -206,14 +206,28 @@ func Setup(
 				return util.ErrorResponse(err)
 			}
 			roomID := vars["roomID"]
-			userID := vars["userID"]
+			eventID := vars["eventID"]
+			queryVars := httpReq.URL.Query()
+			remoteVersions := []gomatrixserverlib.RoomVersion{}
+			if vers, ok := queryVars["ver"]; ok {
+				// The remote side supplied a ?=ver so use that to build up the list
+				// of supported room versions
+				for _, v := range vers {
+					remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersion(v))
+				}
+			} else {
+				// The remote side didn't supply a ?ver= so just assume that they only
+				// support room version 1, as per the spec
+				// https://matrix.org/docs/spec/server_server/r0.1.3#get-matrix-federation-v1-make-join-roomid-userid
+				remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersionV1)
+			}
 			return MakeJoin(
-				httpReq, request, cfg, query, roomID, userID,
+				httpReq, request, cfg, query, roomID, eventID, remoteVersions,
 			)
 		},
 	)).Methods(http.MethodGet)
 
-	v2fedmux.Handle("/send_join/{roomID}/{userID}", common.MakeFedAPI(
+	v2fedmux.Handle("/send_join/{roomID}/{eventID}", common.MakeFedAPI(
 		"federation_send_join", cfg.Matrix.ServerName, keys,
 		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
 			vars, err := common.URLDecodeMapValues(mux.Vars(httpReq))
@@ -221,14 +235,14 @@ func Setup(
 				return util.ErrorResponse(err)
 			}
 			roomID := vars["roomID"]
-			userID := vars["userID"]
+			eventID := vars["eventID"]
 			return SendJoin(
-				httpReq, request, cfg, query, producer, keys, roomID, userID,
+				httpReq, request, cfg, query, producer, keys, roomID, eventID,
 			)
 		},
 	)).Methods(http.MethodPut)
 
-	v1fedmux.Handle("/make_leave/{roomID}/{userID}", common.MakeFedAPI(
+	v1fedmux.Handle("/make_leave/{roomID}/{eventID}", common.MakeFedAPI(
 		"federation_make_leave", cfg.Matrix.ServerName, keys,
 		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
 			vars, err := common.URLDecodeMapValues(mux.Vars(httpReq))
@@ -236,14 +250,14 @@ func Setup(
 				return util.ErrorResponse(err)
 			}
 			roomID := vars["roomID"]
-			userID := vars["userID"]
+			eventID := vars["eventID"]
 			return MakeLeave(
-				httpReq, request, cfg, query, roomID, userID,
+				httpReq, request, cfg, query, roomID, eventID,
 			)
 		},
 	)).Methods(http.MethodGet)
 
-	v2fedmux.Handle("/send_leave/{roomID}/{userID}", common.MakeFedAPI(
+	v2fedmux.Handle("/send_leave/{roomID}/{eventID}", common.MakeFedAPI(
 		"federation_send_leave", cfg.Matrix.ServerName, keys,
 		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
 			vars, err := common.URLDecodeMapValues(mux.Vars(httpReq))
@@ -251,9 +265,9 @@ func Setup(
 				return util.ErrorResponse(err)
 			}
 			roomID := vars["roomID"]
-			userID := vars["userID"]
+			eventID := vars["eventID"]
 			return SendLeave(
-				httpReq, request, cfg, producer, keys, roomID, userID,
+				httpReq, request, cfg, producer, keys, roomID, eventID,
 			)
 		},
 	)).Methods(http.MethodPut)

federationapi/routing/state.go

@@ -107,7 +107,6 @@ func getState(
 		return nil, &util.JSONResponse{Code: http.StatusNotFound, JSON: nil}
 	}
 
-	prevEventIDs := getIDsFromEventRef(event.PrevEvents())
 	authEventIDs := getIDsFromEventRef(event.AuthEvents())
 
 	var response api.QueryStateAndAuthChainResponse
@@ -115,7 +114,7 @@ func getState(
 		ctx,
 		&api.QueryStateAndAuthChainRequest{
 			RoomID:       roomID,
-			PrevEventIDs: prevEventIDs,
+			PrevEventIDs: []string{eventID},
 			AuthEventIDs: authEventIDs,
 		},
 		&response,

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/matrix-org/go-http-js-libp2p v0.0.0-20200318135427-31631a9ef51f
 	github.com/matrix-org/go-sqlite3-js v0.0.0-20200325174927-327088cdef10
 	github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26
-	github.com/matrix-org/gomatrixserverlib v0.0.0-20200402141635-4a6e1ade46f8
+	github.com/matrix-org/gomatrixserverlib v0.0.0-20200409140603-8b9a51fe9b89
 	github.com/matrix-org/naffka v0.0.0-20200127221512-0716baaabaf1
 	github.com/matrix-org/util v0.0.0-20190711121626-527ce5ddefc7
 	github.com/mattn/go-sqlite3 v2.0.2+incompatible
@@ -23,9 +23,9 @@ require (
 	github.com/tidwall/pretty v1.0.1 // indirect
 	github.com/uber/jaeger-client-go v2.22.1+incompatible
 	github.com/uber/jaeger-lib v2.2.0+incompatible
-	go.uber.org/atomic v1.6.0 // indirect
+	go.uber.org/atomic v1.6.0
 	golang.org/x/crypto v0.0.0-20200115085410-6d4e4cb37c7d
-	golang.org/x/net v0.0.0-20190909003024-a7b16738d86b // indirect
+	golang.org/x/tools v0.0.0-20200402223321-bcf690261a44 // indirect
 	gopkg.in/Shopify/sarama.v1 v1.20.1
 	gopkg.in/h2non/bimg.v1 v1.0.18
 	gopkg.in/yaml.v2 v2.2.5

go.sum

@@ -130,8 +130,8 @@ github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26 h1:Hr3zjRsq2bh
 github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26/go.mod h1:3fxX6gUjWyI/2Bt7J1OLhpCzOfO/bB3AiX0cJtEKud0=
 github.com/matrix-org/gomatrixserverlib v0.0.0-20200124100636-0c2ec91d1df5 h1:kmRjpmFOenVpOaV/DRlo9p6z/IbOKlUC+hhKsAAh8Qg=
 github.com/matrix-org/gomatrixserverlib v0.0.0-20200124100636-0c2ec91d1df5/go.mod h1:FsKa2pWE/bpQql9H7U4boOPXFoJX/QcqaZZ6ijLkaZI=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20200402141635-4a6e1ade46f8 h1:VZ7xGklSuzU9geMekuxKO4FvUBUaPjP+8IkcwzQtqOI=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20200409140603-8b9a51fe9b89 h1:YAlUJK/Ty2ZrP/DL41CiR0Cp3pteshnyIS420KVs220=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20200402141635-4a6e1ade46f8/go.mod h1:FsKa2pWE/bpQql9H7U4boOPXFoJX/QcqaZZ6ijLkaZI=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20200409140603-8b9a51fe9b89/go.mod h1:FsKa2pWE/bpQql9H7U4boOPXFoJX/QcqaZZ6ijLkaZI=
 github.com/matrix-org/naffka v0.0.0-20200127221512-0716baaabaf1 h1:osLoFdOy+ChQqVUn2PeTDETFftVkl4w9t/OW18g3lnk=
 github.com/matrix-org/naffka v0.0.0-20200127221512-0716baaabaf1/go.mod h1:cXoYQIENbdWIQHt1SyCo6Bl3C3raHwJ0wgVrXHSqf+A=
 github.com/matrix-org/util v0.0.0-20171127121716-2e2df66af2f5 h1:W7l5CP4V7wPyPb4tYE11dbmeAOwtFQBTW0rf4OonOS8=
@@ -253,6 +253,7 @@ github.com/uber/jaeger-lib v1.5.0/go.mod h1:ComeNDZlWwrWnDv8aPp0Ba6+uUTzImX/Aaua
 github.com/uber/jaeger-lib v2.2.0+incompatible h1:MxZXOiR2JuoANZ3J6DE/U0kSFv/eJ/GfSYVCjK7dyaw=
 github.com/uber/jaeger-lib v2.2.0+incompatible/go.mod h1:ComeNDZlWwrWnDv8aPp0Ba6+uUTzImX/AauajbLI56U=
 github.com/x-cray/logrus-prefixed-formatter v0.5.2/go.mod h1:2duySbKsL6M18s5GU7VPsoEPHyzalCE06qoARUCeBBE=
+github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 go.opencensus.io v0.22.3/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.uber.org/atomic v1.3.0 h1:vs7fgriifsPbGdK3bNuMWapNn3qnZhCRXc19NRdq010=
 go.uber.org/atomic v1.3.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
@@ -276,6 +277,8 @@ golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvx
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
+golang.org/x/mod v0.2.0 h1:KU7oHjnv3XNWfa5COkzUifxZmxp1TyI7ImMXqFxLwvQ=
+golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
@@ -288,8 +291,8 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190613194153-d28f0bde5980/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859 h1:R/3boaszxrf1GEUWTVDzSKVwLmSJpwZ1yqXm8j0v2QI=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20190909003024-a7b16738d86b h1:XfVGCX+0T4WOStkaOsJRllbsiImhB2jgVBGc9L0lPGc=
+golang.org/x/net v0.0.0-20200226121028-0de0cce0169b h1:0mm1VjtFUOIlE1SbDlwjYaDxZVDP2S5ou6y0gSgXHu8=
-golang.org/x/net v0.0.0-20190909003024-a7b16738d86b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -324,7 +327,11 @@ golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c h1:IGkKhmfzcztjm6gYkykvu/NiS8kaqbCWAEWWAyf8J5U=
 golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20200402223321-bcf690261a44 h1:bMm0eoDiGkM5VfIyKjxDvoflW5GLp7+VCo+60n8F+TE=
+golang.org/x/tools v0.0.0-20200402223321-bcf690261a44/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=

roomserver/api/query.go

@@ -203,6 +203,9 @@ type QueryStateAndAuthChainRequest struct {
 	PrevEventIDs []string `json:"prev_event_ids"`
 	// The list of auth events for the event. Used to calculate the auth chain
 	AuthEventIDs []string `json:"auth_event_ids"`
+	// Should state resolution be ran on the result events?
+	// TODO: check call sites and remove if we always want to do state res
+	ResolveState bool `json:"resolve_state"`
 }
 
 // QueryStateAndAuthChainResponse is a response to QueryStateAndAuthChain

roomserver/query/query.go

@@ -132,7 +132,7 @@ func (r *RoomserverQueryAPI) QueryLatestEventsAndState(
 		return err
 	}
 
-	// Look up the currrent state for the requested tuples.
+	// Look up the current state for the requested tuples.
 	stateEntries, err := roomState.LoadStateAtSnapshotForStringTuples(
 		ctx, currentStateSnapshotNID, request.StateToFetch,
 	)
@@ -736,6 +736,14 @@ func (r *RoomserverQueryAPI) QueryStateAndAuthChain(
 		return err
 	}
 
+	if request.ResolveState {
+		if stateEvents, err = state.ResolveConflictsAdhoc(
+			roomVersion, stateEvents, authEvents,
+		); err != nil {
+			return err
+		}
+	}
+
 	for _, event := range stateEvents {
 		response.StateEvents = append(response.StateEvents, event.Headered(roomVersion))
 	}

roomserver/state/state.go

@@ -18,7 +18,6 @@ package state
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"sort"
 	"time"
@@ -681,6 +680,83 @@ func (v StateResolution) calculateStateAfterManyEvents(
 	return
 }
 
+// ResolveConflictsAdhoc is a helper function to assist the query API in
+// performing state resolution when requested. This is a different code
+// path to the rest of state.go because this assumes you already have
+// gomatrixserverlib.Event objects and not just a bunch of NIDs like
+// elsewhere in the state resolution.
+// TODO: Some of this can possibly be deduplicated
+func ResolveConflictsAdhoc(
+	version gomatrixserverlib.RoomVersion,
+	events []gomatrixserverlib.Event,
+	authEvents []gomatrixserverlib.Event,
+) ([]gomatrixserverlib.Event, error) {
+	type stateKeyTuple struct {
+		Type     string
+		StateKey string
+	}
+
+	// Prepare our data structures.
+	eventMap := make(map[stateKeyTuple][]gomatrixserverlib.Event)
+	var conflicted, notConflicted, resolved []gomatrixserverlib.Event
+
+	// Run through all of the events that we were given and sort them
+	// into a map, sorted by (event_type, state_key) tuple. This means
+	// that we can easily spot events that are "conflicted", e.g.
+	// there are duplicate values for the same tuple key.
+	for _, event := range events {
+		if event.StateKey() == nil {
+			// Ignore events that are not state events.
+			continue
+		}
+		// Append the events if there is already a conflicted list for
+		// this tuple key, create it if not.
+		tuple := stateKeyTuple{event.Type(), *event.StateKey()}
+		if _, ok := eventMap[tuple]; ok {
+			eventMap[tuple] = append(eventMap[tuple], event)
+		} else {
+			eventMap[tuple] = []gomatrixserverlib.Event{event}
+		}
+	}
+
+	// Split out the events in the map into conflicted and unconflicted
+	// buckets. The conflicted events will be ran through state res,
+	// whereas unconfliced events will always going to appear in the
+	// final resolved state.
+	for _, list := range eventMap {
+		if len(list) > 1 {
+			conflicted = append(conflicted, list...)
+		} else {
+			notConflicted = append(notConflicted, list...)
+		}
+	}
+
+	// Work out which state resolution algorithm we want to run for
+	// the room version.
+	stateResAlgo, err := version.StateResAlgorithm()
+	if err != nil {
+		return nil, err
+	}
+	switch stateResAlgo {
+	case gomatrixserverlib.StateResV1:
+		// Currently state res v1 doesn't handle unconflicted events
+		// for us, like state res v2 does, so we will need to add the
+		// unconflicted events into the state ourselves.
+		// TODO: Fix state res v1 so this is handled for the caller.
+		resolved = gomatrixserverlib.ResolveStateConflicts(conflicted, authEvents)
+		resolved = append(resolved, notConflicted...)
+	case gomatrixserverlib.StateResV2:
+		// TODO: auth difference here?
+		resolved = gomatrixserverlib.ResolveStateConflictsV2(conflicted, notConflicted, authEvents, authEvents)
+	default:
+		return nil, fmt.Errorf("unsupported state resolution algorithm %v", stateResAlgo)
+	}
+
+	// Return the final resolved state events, including both the
+	// resolved set of conflicted events, and the unconflicted events.
+	return resolved, nil
+}
+
 func (v StateResolution) resolveConflicts(
 	ctx context.Context, version gomatrixserverlib.RoomVersion,
 	notConflicted, conflicted []types.StateEntry,
@@ -695,7 +771,7 @@ func (v StateResolution) resolveConflicts(
 	case gomatrixserverlib.StateResV2:
 		return v.resolveConflictsV2(ctx, notConflicted, conflicted)
 	}
-	return nil, errors.New("unsupported state resolution algorithm")
+	return nil, fmt.Errorf("unsupported state resolution algorithm %v", stateResAlgo)
 }
 
 // resolveConflicts resolves a list of conflicted state entries. It takes two lists.

roomserver/version/version.go

@@ -43,12 +43,12 @@ var roomVersions = map[gomatrixserverlib.RoomVersion]RoomVersionDescription{
 		Stable:    true,
 	},
 	gomatrixserverlib.RoomVersionV3: RoomVersionDescription{
-		Supported: false,
+		Supported: true,
-		Stable:    false,
+		Stable:    true,
 	},
 	gomatrixserverlib.RoomVersionV4: RoomVersionDescription{
-		Supported: false,
+		Supported: true,
-		Stable:    false,
+		Stable:    true,
 	},
 	gomatrixserverlib.RoomVersionV5: RoomVersionDescription{
 		Supported: false,

sytest-blacklist

@@ -32,3 +32,6 @@ Alias creators can delete canonical alias with no ops
 # Blacklisted because we need to implement v2 invite endpoints for room versions
 # to be supported (currently fails with M_UNSUPPORTED_ROOM_VERSION) 
 Inbound federation rejects invites which are not signed by the sender
+
+# Blacklisted because we don't support ignores yet
+Ignore invite in incremental sync

sytest-whitelist

@@ -215,7 +215,6 @@ Guest users can sync from default guest_access rooms if joined
 Real non-joined users cannot room initalSync for non-world_readable rooms
 Push rules come down in an initial /sync
 Regular users can add and delete aliases in the default room configuration
-Regular users can add and delete aliases when m.room.aliases is restricted
 GET /r0/capabilities is not public
 GET /joined_rooms lists newly-created room
 /joined_rooms returns only joined rooms
@@ -225,6 +224,7 @@ Remote user can backfill in a room with version 1
 POST /createRoom creates a room with the given version
 POST /createRoom rejects attempts to create rooms with numeric versions
 POST /createRoom rejects attempts to create rooms with unknown versions
+Regular users can add and delete aliases when m.room.aliases is restricted
 User can create and send/receive messages in a room with version 2
 local user can join room with version 2
 remote user can join room with version 2
@@ -232,3 +232,16 @@ User can invite local user to room with version 2
 Remote user can backfill in a room with version 2
 Inbound federation accepts attempts to join v2 rooms from servers with support
 Outbound federation can send invites via v2 API
+User can create and send/receive messages in a room with version 3
+local user can join room with version 3
+Remote user can backfill in a room with version 3
+User can create and send/receive messages in a room with version 4
+local user can join room with version 4
+remote user can join room with version 3
+remote user can join room with version 4
+Remote user can backfill in a room with version 4
+# We don't support ignores yet, so ignore this for now - ha ha.
+# Ignore invite in incremental sync
+Outbound federation can send invites via v2 API
+User can invite local user to room with version 3
+User can invite local user to room with version 4