Fix exceptions when dealing with redactions

When we got a redaction event, we were adding the entire (circular) MatrixEvent
object for the redaction to the redacted event, which would then cause
exceptions down the line (particularly when dealing with gappy timelines).

We should only be adding the raw event.

Fixes (hopefully) https://github.com/vector-im/vector-web/issues/1389.

lib/models/event.js

@@ -248,13 +248,25 @@ module.exports.MatrixEvent.prototype = {
      * Update the content of an event in the same way it would be by the server
      * if it were redacted before it was sent to us
      *
-     * @param {Object} the raw event causing the redaction
+     * @param {module:models/event.MatrixEvent} redaction_event
+     *     event causing the redaction
      */
     makeRedacted: function(redaction_event) {
+        // quick sanity-check
+        if (!redaction_event.event) {
+            throw new Error("invalid redaction_event in makeRedacted");
+        }
+
+        // we attempt to replicate what we would see from the server if
+        // the event had been redacted before we saw it.
+        //
+        // The server removes (most of) the content of the event, and adds a
+        // "redacted_because" key to the unsigned section containing the
+        // redacted event.
         if (!this.event.unsigned) {
             this.event.unsigned = {};
         }
-        this.event.unsigned.redacted_because = redaction_event;
+        this.event.unsigned.redacted_because = redaction_event.event;
 
         var key;
         for (key in this.event) {

spec/integ/matrix-client-event-timeline.spec.js

@@ -655,4 +655,70 @@ describe("MatrixClient event timelines", function() {
             }).catch(utils.failTest);
         });
     });
+
+
+    it("should handle gappy syncs after redactions", function(done) {
+        // https://github.com/vector-im/vector-web/issues/1389
+
+        // a state event, followed by a redaction thereof
+        var event = utils.mkMembership({
+            room: roomId, mship: "join", user: otherUserId
+        });
+        var redaction = utils.mkEvent({
+            type: "m.room.redaction",
+            room_id: roomId,
+            sender: otherUserId,
+            content: {}
+        });
+        redaction.redacts = event.event_id;
+
+        var syncData = {
+            next_batch: "batch1",
+            rooms: {
+                join: {},
+            },
+        };
+        syncData.rooms.join[roomId] = {
+            timeline: {
+                events: [
+                    event,
+                    redaction,
+                ],
+                limited: false,
+            },
+        };
+        httpBackend.when("GET", "/sync").respond(200, syncData);
+
+        httpBackend.flush().then(function() {
+            var room = client.getRoom(roomId);
+            var tl = room.getLiveTimeline();
+            expect(tl.getEvents().length).toEqual(3);
+            expect(tl.getEvents()[1].isRedacted()).toBe(true);
+
+            var sync2 = {
+                next_batch: "batch2",
+                rooms: {
+                    join: {},
+                },
+            };
+            sync2.rooms.join[roomId] = {
+                timeline: {
+                    events: [
+                        utils.mkMessage({
+                            room: roomId, user: otherUserId, msg: "world"
+                        }),
+                    ],
+                    limited: true,
+                    prev_batch: "newerTok",
+                },
+            };
+            httpBackend.when("GET", "/sync").respond(200, sync2);
+
+            return httpBackend.flush();
+        }).then(function() {
+            var room = client.getRoom(roomId);
+            var tl = room.getLiveTimeline();
+            expect(tl.getEvents().length).toEqual(1);
+        }).catch(utils.failTest).done(done);
+    });
 });

spec/test-utils.js

@@ -48,7 +48,7 @@ module.exports.mock = function(constr, name) {
  * @param {Object} opts Values for the event.
  * @param {string} opts.type The event.type
  * @param {string} opts.room The event.room_id
- * @param {string} opts.user The event.user_id
+ * @param {string} opts.sender The event.sender
  * @param {string} opts.skey Optional. The state key (auto inserts empty string)
  * @param {Object} opts.content The event.content
  * @param {boolean} opts.event True to make a MatrixEvent.
@@ -61,7 +61,7 @@ module.exports.mkEvent = function(opts) {
     var event = {
         type: opts.type,
         room_id: opts.room,
-        sender: opts.user,
+        sender: opts.sender || opts.user, // opts.user for backwards-compat
         content: opts.content,
         event_id: "$" + Math.random() + "-" + Math.random()
     };
@@ -88,7 +88,7 @@ module.exports.mkPresence = function(opts) {
     var event = {
         event_id: "$" + Math.random() + "-" + Math.random(),
         type: "m.presence",
-        sender: opts.user,
+        sender: opts.sender || opts.user, // opts.user for backwards-compat
         content: {
             avatar_url: opts.url,
             displayname: opts.name,
@@ -104,8 +104,8 @@ module.exports.mkPresence = function(opts) {
  * @param {Object} opts Values for the membership.
  * @param {string} opts.room The room ID for the event.
  * @param {string} opts.mship The content.membership for the event.
- * @param {string} opts.user The user ID for the event.
- * @param {string} opts.skey The other user ID for the event if applicable
+ * @param {string} opts.sender The sender user ID for the event.
+ * @param {string} opts.skey The target user ID for the event if applicable
  * e.g. for invites/bans.
  * @param {string} opts.name The content.displayname for the event.
  * @param {string} opts.url The content.avatar_url for the event.
@@ -115,7 +115,7 @@ module.exports.mkPresence = function(opts) {
 module.exports.mkMembership = function(opts) {
     opts.type = "m.room.member";
     if (!opts.skey) {
-        opts.skey = opts.user;
+        opts.skey = opts.sender || opts.user;
     }
     if (!opts.mship) {
         throw new Error("Missing .mship => " + JSON.stringify(opts));