check power levels without relying on membership

as this might not be known for the syncing user.
instead, add a method to room which always knows the syncing user's membership

CHANGELOG.md

@@ -1,3 +1,17 @@
+Changes in [0.11.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v0.11.0) (TDB)
+==================================================================================================
+[Full Changelog](https://github.com/matrix-org/matrix-js-sdk/compare/v0.10.9...v0.11.0)
+
+ * Support for lazy loading members. This should improve performance for
+   users who joined big rooms a lot. Pass to `lazyLoadMembers = true` option when calling `startClient`.
+
+BREAKING CHANGES
+----------------
+
+ * `MatrixClient::startClient` now returns a Promise. No method should be called on the client before that promise resolves. Before this method didn't return anything.
+ * A new `CATCHUP` sync state, emitted by `MatrixClient#"sync"` and returned by `MatrixClient::getSyncState()`, when doing initial sync after the `ERROR` state. See `MatrixClient` documentation for details.
+ * `RoomState::maySendEvent('m.room.message', userId)` & `RoomState::maySendMessage(userId)` do not check the membership of the user anymore, only the power level. To check if the syncing user is allowed to write in a room, use `Room::maySendMessage()` as `RoomState` is not always aware of the syncing user's membership anymore, in case lazy loading of members is enabled.
+
 Changes in [0.10.9](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v0.10.9) (2018-09-03)
 ==================================================================================================
 [Full Changelog](https://github.com/matrix-org/matrix-js-sdk/compare/v0.10.9-rc.2...v0.10.9)
@@ -36,19 +50,6 @@ Changes in [0.10.9-rc.1](https://github.com/matrix-org/matrix-js-sdk/releases/ta
  * Lazy loading of room members
    [\#691](https://github.com/matrix-org/matrix-js-sdk/pull/691)
 
-BREAKING CHANGE
----------------
-
- * `MatrixClient::startClient` now returns a Promise. No method should be called on the client before that promise resolves. Before this method didn't return anything.
- * A new `CATCHUP` sync state, emitted by `MatrixClient#"sync"` and returned by `MatrixClient::getSyncState()`, when doing initial sync after the `ERROR` state. See `MatrixClient` documentation for details.
-
-Changes in [0.11.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v0.11.0) (TDB)
-==================================================================================================
-[Full Changelog](https://github.com/matrix-org/matrix-js-sdk/compare/v0.10.6...v0.11.0)
-
- * Support for lazy loading members. This should improve performance for
-   users who joined big rooms a lot. Pass to `lazyLoadMembers = true` option when calling `startClient`.
-
 Changes in [0.10.8](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v0.10.8) (2018-08-20)
 ==================================================================================================
 [Full Changelog](https://github.com/matrix-org/matrix-js-sdk/compare/v0.10.8-rc.1...v0.10.8)

spec/unit/room-state.spec.js

@@ -447,13 +447,6 @@ describe("RoomState", function() {
     });
 
     describe("maySendStateEvent", function() {
-        it("should say non-joined members may not send state",
-        function() {
-            expect(state.maySendStateEvent(
-                'm.room.name', "@nobody:nowhere",
-            )).toEqual(false);
-        });
-
         it("should say any member may send state with no power level event",
         function() {
             expect(state.maySendStateEvent('m.room.name', userA)).toEqual(true);
@@ -640,14 +633,6 @@ describe("RoomState", function() {
     });
 
     describe("maySendEvent", function() {
-        it("should say non-joined members may not send events",
-        function() {
-            expect(state.maySendEvent(
-                'm.room.message', "@nobody:nowhere",
-            )).toEqual(false);
-            expect(state.maySendMessage("@nobody:nowhere")).toEqual(false);
-        });
-
         it("should say any member may send events with no power level event",
         function() {
             expect(state.maySendEvent('m.room.message', userA)).toEqual(true);

spec/unit/room.spec.js

@@ -1400,7 +1400,7 @@ describe("Room", function() {
 
     describe("getMyMembership", function() {
         it("should return synced membership if membership isn't available yet",
-        async function() {
+        function() {
             const room = new Room(roomId, null, userA);
             room.setSyncedMembership("invite");
             expect(room.getMyMembership()).toEqual("invite");
@@ -1434,4 +1434,17 @@ describe("Room", function() {
             expect(room.guessDMUserId()).toEqual(userA);
         });
     });
+
+    describe("maySendMessage", function() {
+        it("should return false if synced membership not join",
+        function() {
+            const room = new Room(roomId, null, userA);
+            room.setSyncedMembership("invite");
+            expect(room.maySendMessage()).toEqual(false);
+            room.setSyncedMembership("leave");
+            expect(room.maySendMessage()).toEqual(false);
+            room.setSyncedMembership("join");
+            expect(room.maySendMessage()).toEqual(true);
+        });
+    });
 });

src/models/room-state.js

@@ -667,11 +667,6 @@ RoomState.prototype.maySendStateEvent = function(stateEventType, userId) {
  *                        according to the room's state.
  */
 RoomState.prototype._maySendEventOfType = function(eventType, userId, state) {
-    const member = this.getMember(userId);
-    if (!member || member.membership == 'leave') {
-        return false;
-    }
-
     const power_levels_event = this.getStateEvents('m.room.power_levels', '');
 
     let power_levels;
@@ -679,25 +674,34 @@ RoomState.prototype._maySendEventOfType = function(eventType, userId, state) {
 
     let state_default = 0;
     let events_default = 0;
+    let powerLevel = 0;
     if (power_levels_event) {
         power_levels = power_levels_event.getContent();
         events_levels = power_levels.events || {};
 
-        if (utils.isNumber(power_levels.state_default)) {
+        if (Number.isFinite(power_levels.state_default)) {
             state_default = power_levels.state_default;
         } else {
             state_default = 50;
         }
-        if (utils.isNumber(power_levels.events_default)) {
+
+        const userPowerLevel = power_levels.users && power_levels.users[userId];
+        if (Number.isFinite(userPowerLevel)) {
+            powerLevel = userPowerLevel;
+        } else if(Number.isFinite(power_levels.users_default)) {
+            powerLevel = power_levels.users_default;
+        }
+
+        if (Number.isFinite(power_levels.events_default)) {
             events_default = power_levels.events_default;
         }
     }
 
     let required_level = state ? state_default : events_default;
-    if (utils.isNumber(events_levels[eventType])) {
+    if (Number.isFinite(events_levels[eventType])) {
         required_level = events_levels[eventType];
     }
-    return member.powerLevel >= required_level;
+    return powerLevel >= required_level;
 };
 
 /**

src/models/room.js

@@ -1485,6 +1485,17 @@ Room.prototype.getAccountData = function(type) {
     return this.accountData[type];
 };
 
+
+/**
+ * Returns wheter the syncing user has permission to send a message in the room
+ * @return {boolean} true if the user should be permitted to send
+ *                   message events into the room.
+ */
+Room.prototype.maySendMessage = function() {
+    return this.getMyMembership() === 'join' &&
+        this.currentState.maySendEvent('m.room.message', this.myUserId);
+};
+
 /**
  * This is an internal method. Calculates the name of the room from the current
  * room state.