From 102b67ec9bb41900def65bdf7464fac208a979a9 Mon Sep 17 00:00:00 2001
From: Vincent Koc <vincentkoc@ieee.org>
Date: Tue, 11 Aug 2026 22:27:26 +0800
Subject: [PATCH] fix(slack): retry transient member event failures

---
 .../slack/src/monitor/events/members.test.ts  | 25 +++++++++++++++++++
 .../slack/src/monitor/events/members.ts       |  1 +
 2 files changed, 26 insertions(+)

diff --git a/extensions/slack/src/monitor/events/members.test.ts b/extensions/slack/src/monitor/events/members.test.ts
index e42aa6906529..b6823f13a504 100644
--- a/extensions/slack/src/monitor/events/members.test.ts
+++ b/extensions/slack/src/monitor/events/members.test.ts
@@ -145,6 +145,31 @@ describe("registerSlackMemberEvents", () => {
     expect(trackEvent).toHaveBeenCalledTimes(1);
   });
 
+  it("logs and rejects transient member lookup failures", async () => {
+    const lookupError = new Error("users.info temporarily unavailable");
+    const harness = initSlackHarness();
+    const runtimeError = vi.fn();
+    harness.ctx.runtime.error = runtimeError;
+    harness.ctx.resolveUserName = vi.fn().mockRejectedValue(lookupError);
+    registerSlackMemberEvents({ ctx: harness.ctx });
+    const handler = harness.getHandler("member_joined_channel");
+    if (!handler) {
+      throw new Error("expected Slack member joined handler");
+    }
+
+    await expect(
+      handler({
+        event: makeMemberEvent(),
+        body: { event_id: "Ev-member-failure" },
+      }),
+    ).rejects.toBe(lookupError);
+
+    expect(runtimeError).toHaveBeenCalledWith(
+      expect.stringContaining("users.info temporarily unavailable"),
+    );
+    expect(memberMocks.enqueue).not.toHaveBeenCalled();
+  });
+
   it("keys each queued event by the envelope occurrence", async () => {
     await runMemberCase({ body: { event_id: "Ev-member-2" } });
 
diff --git a/extensions/slack/src/monitor/events/members.ts b/extensions/slack/src/monitor/events/members.ts
index 3670c6b5b35f..150fbe5c53fc 100644
--- a/extensions/slack/src/monitor/events/members.ts
+++ b/extensions/slack/src/monitor/events/members.ts
@@ -66,6 +66,7 @@ export function registerSlackMemberEvents(params: {
       ctx.runtime.error?.(
         danger(`slack ${paramsLocal.verb} handler failed: ${formatErrorMessage(err)}`),
       );
+      throw err;
     }
   };