From a46d41156d23ba85208b773fd9a5267b01caf861 Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Thu, 23 Apr 2026 06:26:51 +0100
Subject: [PATCH] fix(matrix): ignore stale no-reply events

---
 .../contract/scenario-runtime-shared.ts       | 21 ++++--
 .../src/runners/contract/scenarios.test.ts    | 67 +++++++++++++++++++
 2 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/extensions/qa-matrix/src/runners/contract/scenario-runtime-shared.ts b/extensions/qa-matrix/src/runners/contract/scenario-runtime-shared.ts
index ec89f2b06d4..d4c38496ca4 100644
--- a/extensions/qa-matrix/src/runners/contract/scenario-runtime-shared.ts
+++ b/extensions/qa-matrix/src/runners/contract/scenario-runtime-shared.ts
@@ -583,13 +583,24 @@ export async function runNoReplyExpectedScenario(params: {
     ...(params.mentionUserIds ? { mentionUserIds: params.mentionUserIds } : {}),
     roomId: params.roomId,
   });
+  let observedTriggerEvent = false;
   const result = await client.waitForOptionalRoomEvent({
     observedEvents: params.observedEvents,
-    predicate: (event) =>
-      event.roomId === params.roomId &&
-      event.sender === params.sutUserId &&
-      event.type === "m.room.message" &&
-      (params.replyPredicate?.(event, { driverEventId, token: params.token }) ?? true),
+    predicate: (event) => {
+      if (event.roomId !== params.roomId) {
+        return false;
+      }
+      if (event.eventId === driverEventId) {
+        observedTriggerEvent = true;
+        return false;
+      }
+      return (
+        observedTriggerEvent &&
+        event.sender === params.sutUserId &&
+        event.type === "m.room.message" &&
+        (params.replyPredicate?.(event, { driverEventId, token: params.token }) ?? true)
+      );
+    },
     roomId: params.roomId,
     since: startSince,
     timeoutMs: params.timeoutMs,
diff --git a/extensions/qa-matrix/src/runners/contract/scenarios.test.ts b/extensions/qa-matrix/src/runners/contract/scenarios.test.ts
index db4afe9bb3b..90930e40970 100644
--- a/extensions/qa-matrix/src/runners/contract/scenarios.test.ts
+++ b/extensions/qa-matrix/src/runners/contract/scenarios.test.ts
@@ -590,6 +590,73 @@ describe("matrix live qa scenarios", () => {
     );
   });
 
+  it("ignores stale Matrix SUT replies before a no-reply trigger", async () => {
+    const primeRoom = vi.fn().mockResolvedValue("observer-sync-start");
+    const sendTextMessage = vi.fn().mockResolvedValue("$observer-command-trigger");
+    const waitForOptionalRoomEvent = vi.fn().mockImplementation(async (params) => {
+      expect(
+        params.predicate({
+          eventId: "$previous-reply",
+          kind: "message",
+          relatesTo: {
+            eventId: "$previous-trigger",
+            inReplyToId: "$previous-trigger",
+            isFallingBack: true,
+            relType: "m.thread",
+          },
+          roomId: "!main:matrix-qa.test",
+          sender: "@sut:matrix-qa.test",
+          type: "m.room.message",
+        }),
+      ).toBe(false);
+      expect(
+        params.predicate({
+          eventId: "$observer-command-trigger",
+          kind: "message",
+          roomId: "!main:matrix-qa.test",
+          sender: "@observer:matrix-qa.test",
+          type: "m.room.message",
+        }),
+      ).toBe(false);
+      expect(
+        params.predicate({
+          eventId: "$current-reply",
+          kind: "message",
+          relatesTo: {
+            eventId: "$observer-command-trigger",
+            inReplyToId: "$observer-command-trigger",
+            isFallingBack: true,
+            relType: "m.thread",
+          },
+          roomId: "!main:matrix-qa.test",
+          sender: "@sut:matrix-qa.test",
+          type: "m.room.message",
+        }),
+      ).toBe(true);
+      return {
+        matched: false,
+        since: "observer-sync-next",
+      };
+    });
+
+    createMatrixQaClient.mockReturnValue({
+      primeRoom,
+      sendTextMessage,
+      waitForOptionalRoomEvent,
+    });
+
+    const scenario = MATRIX_QA_SCENARIOS.find(
+      (entry) => entry.id === "matrix-mxid-prefixed-command-block",
+    );
+    expect(scenario).toBeDefined();
+
+    await expect(runMatrixQaScenario(scenario!, matrixQaScenarioContext())).resolves.toMatchObject({
+      artifacts: {
+        driverEventId: "$observer-command-trigger",
+      },
+    });
+  });
+
   it("hot-reloads group allowlist removals inside one running Matrix gateway", async () => {
     const patchGatewayConfig = vi.fn(async () => {});
     const primeRoom = vi.fn().mockResolvedValue("sync-start");