fix(slack): guard allow-from store resolution in monitor auth (#21967)

src/slack/monitor/auth.test.ts

@@ -0,0 +1,40 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { SlackMonitorContext } from "./context.js";
+
+const readChannelAllowFromStoreMock = vi.hoisted(() => vi.fn());
+
+vi.mock("../../pairing/pairing-store.js", () => ({
+  readChannelAllowFromStore: (...args: unknown[]) => readChannelAllowFromStoreMock(...args),
+}));
+
+import { resolveSlackEffectiveAllowFrom } from "./auth.js";
+
+function makeSlackCtx(allowFrom: string[]): SlackMonitorContext {
+  return {
+    allowFrom,
+  } as unknown as SlackMonitorContext;
+}
+
+describe("resolveSlackEffectiveAllowFrom", () => {
+  beforeEach(() => {
+    readChannelAllowFromStoreMock.mockReset();
+  });
+
+  it("falls back to channel config allowFrom when pairing store throws", async () => {
+    readChannelAllowFromStoreMock.mockRejectedValueOnce(new Error("boom"));
+
+    const effective = await resolveSlackEffectiveAllowFrom(makeSlackCtx(["u1"]));
+
+    expect(effective.allowFrom).toEqual(["u1"]);
+    expect(effective.allowFromLower).toEqual(["u1"]);
+  });
+
+  it("treats malformed non-array pairing-store responses as empty", async () => {
+    readChannelAllowFromStoreMock.mockReturnValueOnce(undefined);
+
+    const effective = await resolveSlackEffectiveAllowFrom(makeSlackCtx(["u1"]));
+
+    expect(effective.allowFrom).toEqual(["u1"]);
+    expect(effective.allowFromLower).toEqual(["u1"]);
+  });
+});

src/slack/monitor/auth.ts

@@ -13,13 +13,19 @@ export async function resolveSlackEffectiveAllowFrom(
   options?: { includePairingStore?: boolean },
 ) {
   const includePairingStore = options?.includePairingStore === true;
-  const storeAllowFrom = includePairingStore
+  let storeAllowFrom: string[] = [];
-    ? await readStoreAllowFromForDmPolicy({
+  if (includePairingStore) {
+    try {
+      const resolved = await readStoreAllowFromForDmPolicy({
         provider: "slack",
         accountId: ctx.accountId,
         dmPolicy: ctx.dmPolicy,
-      })
+      });
-    : [];
+      storeAllowFrom = Array.isArray(resolved) ? resolved : [];
+    } catch {
+      storeAllowFrom = [];
+    }
+  }
   const allowFrom = normalizeAllowList([...ctx.allowFrom, ...storeAllowFrom]);
   const allowFromLower = normalizeAllowListLower(allowFrom);
   return { allowFrom, allowFromLower };