From 00d8f81bddcfa301521a0ee7311c56da287ddab3 Mon Sep 17 00:00:00 2001
From: Bruno Windels <bruno@windels.cloud>
Date: Wed, 5 May 2021 19:04:26 +0200
Subject: [PATCH] clear all room state before rejoining room

---
 src/matrix/room/Room.js                         |  3 +++
 src/matrix/storage/idb/stores/RoomStateStore.js | 13 +++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/matrix/room/Room.js b/src/matrix/room/Room.js
index 61e3ff2e..00a97bcf 100644
--- a/src/matrix/room/Room.js
+++ b/src/matrix/room/Room.js
@@ -251,6 +251,9 @@ export class Room extends EventEmitter {
         log.set("id", this.id);
         const isRejoin = summaryChanges.membership === "join" && this.membership !== "join";
         if (isRejoin) {
+            // remove all room state before calling syncWriter,
+            // so no old state sticks around
+            txn.roomState.removeAllForRoom(this.id);
             this._summary.tryRemoveArchive(txn);
         }
         const {entries: newEntries, newLiveKey, memberChanges} =
diff --git a/src/matrix/storage/idb/stores/RoomStateStore.js b/src/matrix/storage/idb/stores/RoomStateStore.js
index 0cec87bc..4b5ea118 100644
--- a/src/matrix/storage/idb/stores/RoomStateStore.js
+++ b/src/matrix/storage/idb/stores/RoomStateStore.js
@@ -14,17 +14,19 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+const MAX_UNICODE = "\u{10FFFF}";
+
 export class RoomStateStore {
 	constructor(idbStore) {
 		this._roomStateStore = idbStore;
 	}
 
 	async getAllForType(type) {
-
+		throw new Error("unimplemented");
 	}
 
 	async get(type, stateKey) {
-        
+        throw new Error("unimplemented");
 	}
 
 	async set(roomId, event) {
@@ -32,4 +34,11 @@ export class RoomStateStore {
         const entry = {roomId, event, key};
 		return this._roomStateStore.put(entry);
 	}
+
+	removeAllForRoom(roomId) {
+		// exclude both keys as they are theoretical min and max,
+		// but we should't have a match for just the room id, or room id with max
+		const range = IDBKeyRange.bound(roomId, `${roomId}|${MAX_UNICODE}`, true, true);
+		this._roomStateStore.delete(range);
+	}
 }