From ccd825fb39477b8340946907e6977078f01f879c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Svaj=C5=ABnas=20Budrys?=
 <93791044+svajunas-budrys@users.noreply.github.com>
Date: Thu, 4 Sep 2025 12:31:26 +0300
Subject: [PATCH] Remove knock state on join (#4977)

Signed-off-by: Svajunas Budrys <svajunas.budrys.sb@gmail.com>
---
 spec/unit/sync-accumulator.spec.ts | 43 ++++++++++++++++++++++++++++++
 src/sync-accumulator.ts            |  5 +++-
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/spec/unit/sync-accumulator.spec.ts b/spec/unit/sync-accumulator.spec.ts
index 89623eeee..22d333600 100644
--- a/spec/unit/sync-accumulator.spec.ts
+++ b/spec/unit/sync-accumulator.spec.ts
@@ -571,6 +571,49 @@ describe("SyncAccumulator", function () {
         expect(sa.getJSON().roomsData.knock["!knock:bar"]).toBeUndefined();
     });
 
+    it("should delete knock state when room transitions from knock to join", () => {
+        const initKnockState = makeKnockState();
+        sa.accumulate(
+            syncSkeleton(
+                {},
+                {},
+                {},
+                {
+                    knock_state: initKnockState,
+                },
+            ),
+        );
+        expect(sa.getJSON().roomsData.knock["!knock:bar"].knock_state).toBe(initKnockState);
+
+        // Room transitions from knock to join (e.g., after approval and joining)
+        const joinState = {
+            account_data: { events: [] },
+            ephemeral: { events: [] },
+            unread_notifications: {},
+            state: {
+                events: [member("bob", KnownMembership.Join)],
+            },
+        };
+
+        const syncResponse = {
+            next_batch: "abc",
+            rooms: {
+                join: {
+                    "!knock:bar": joinState,
+                },
+                invite: {},
+                leave: {},
+            },
+        } as unknown as ISyncResponse;
+
+        sa.accumulate(syncResponse);
+
+        expect(sa.getJSON().roomsData.knock["!knock:bar"]).toBeUndefined();
+        expect(sa.getJSON().roomsData.join["!knock:bar"].state?.events[0]?.content.membership).toEqual(
+            KnownMembership.Join,
+        );
+    });
+
     it("should accumulate read receipts", () => {
         const receipt1 = {
             type: "m.receipt",
diff --git a/src/sync-accumulator.ts b/src/sync-accumulator.ts
index 44638d077..816b45de7 100644
--- a/src/sync-accumulator.ts
+++ b/src/sync-accumulator.ts
@@ -317,7 +317,10 @@ export class SyncAccumulator {
                 break;
 
             case Category.Join:
-                if (this.inviteRooms[roomId]) {
+                if (this.knockRooms[roomId]) {
+                    // delete knock state on join
+                    delete this.knockRooms[roomId];
+                } else if (this.inviteRooms[roomId]) {
                     // (1)
                     // was previously invite, now join. We expect /sync to give
                     // the entire state and timeline on 'join', so delete previous