fix(desktop): preserve huddle community bootstrap

Co-authored-by: Rizz <302abe414ca6e3134763d2539bfcf145aea2a63fe5f8455204ed602fd40cf381@buzz.block.builderlab.xyz>
Signed-off-by: Taylor Ho <taylorkmho@gmail.com>

desktop/src/app/companionWindow.test.mjs

@@ -3,6 +3,7 @@ import { describe, it } from "node:test";
 
 import {
   acceptsNativeDeepLinks,
+  companionCommunityBootstrap,
   companionCommunityIdForHash,
   companionWindowKindForLabel,
 } from "./companionWindow.ts";
@@ -30,6 +31,35 @@ describe("acceptsNativeDeepLinks", () => {
   });
 });
 
+describe("companionCommunityBootstrap", () => {
+  it("lets huddle companions boot through normal community selection", () => {
+    assert.deepEqual(companionCommunityBootstrap("huddle", ""), {
+      initialActiveCommunityId: undefined,
+      missingRequiredCommunity: false,
+    });
+  });
+
+  it("rejects agent activity companions without community context", () => {
+    assert.deepEqual(companionCommunityBootstrap("agent-activity", ""), {
+      initialActiveCommunityId: undefined,
+      missingRequiredCommunity: true,
+    });
+  });
+
+  it("pins agent activity companions to their encoded community", () => {
+    assert.deepEqual(
+      companionCommunityBootstrap(
+        "agent-activity",
+        "#/channels/channel?community=community-one",
+      ),
+      {
+        initialActiveCommunityId: "community-one",
+        missingRequiredCommunity: false,
+      },
+    );
+  });
+});
+
 describe("companionCommunityIdForHash", () => {
   it("reads and decodes immutable community identity from the route", () => {
     assert.equal(

desktop/src/app/companionWindow.ts

@@ -31,12 +31,27 @@ export function companionCommunityIdForHash(hash: string): string | null {
   return new URLSearchParams(hash.slice(query + 1)).get("community");
 }
 
-/** Immutable community selected by a native companion's bootstrap URL. */
-export function companionCommunityId(
-  hash: string = typeof window === "undefined" ? "" : window.location.hash,
-): string | null | undefined {
-  if (currentCompanionWindowKind() === null) return undefined;
-  return companionCommunityIdForHash(hash);
+export type CompanionCommunityBootstrap = {
+  initialActiveCommunityId: string | undefined;
+  missingRequiredCommunity: boolean;
+};
+
+/** Agent activity windows pin their origin community; huddles use normal selection. */
+export function companionCommunityBootstrap(
+  companionKind: CompanionWindowKind | null,
+  hash: string,
+): CompanionCommunityBootstrap {
+  if (companionKind !== "agent-activity") {
+    return {
+      initialActiveCommunityId: undefined,
+      missingRequiredCommunity: false,
+    };
+  }
+  const communityId = companionCommunityIdForHash(hash);
+  return {
+    initialActiveCommunityId: communityId ?? undefined,
+    missingRequiredCommunity: communityId === null,
+  };
 }
 
 /** Whether this realm owns the native pending deep-link queue. */

desktop/src/main.tsx

@@ -13,7 +13,11 @@ import { UpdaterProvider } from "@/features/settings/hooks/UpdaterProvider";
 import { migrateLegacyCommunityStorageBeforeRender } from "@/features/communities/legacyCommunityStorage";
 import { loadCommunities } from "@/features/communities/communityStorage";
 import { CommunitiesProvider } from "@/features/communities/useCommunities";
-import { companionCommunityId, isCompanionWindow } from "@/app/companionWindow";
+import {
+  companionCommunityBootstrap,
+  currentCompanionWindowKind,
+  isCompanionWindow,
+} from "@/app/companionWindow";
 import { CommunityOnboardingProvider } from "@/features/onboarding/communityOnboarding";
 import { ThemeProvider } from "@/shared/theme/ThemeProvider";
 import { EmojiBurstProvider } from "@/shared/ui/EmojiBurstProvider";
@@ -99,17 +103,22 @@ function renderCompanionBootstrapError(message: string) {
 }
 
 function renderApp() {
-  const companion = isCompanionWindow();
-  const companionCommunity = companionCommunityId();
-  if (companion && !companionCommunity) {
+  const companionKind = currentCompanionWindowKind();
+  const companionCommunity = companionCommunityBootstrap(
+    companionKind,
+    window.location.hash,
+  );
+  if (companionCommunity.missingRequiredCommunity) {
     renderCompanionBootstrapError(
       "This window is missing its community context. Close it and try again.",
     );
     return;
   }
   if (
-    companionCommunity &&
-    !loadCommunities().some(({ id }) => id === companionCommunity)
+    companionCommunity.initialActiveCommunityId &&
+    !loadCommunities().some(
+      ({ id }) => id === companionCommunity.initialActiveCommunityId,
+    )
   ) {
     renderCompanionBootstrapError(
       "This community is no longer available. Close this window and open activity again from Buzz.",
@@ -122,7 +131,9 @@ function renderApp() {
       {/* block/buzz#5078 — catch any uncaught render error so a WebKit
           SecurityError from localStorage can't blank the whole window. */}
       <RootErrorBoundary>
-        <CommunitiesProvider initialActiveCommunityId={companionCommunity}>
+        <CommunitiesProvider
+          initialActiveCommunityId={companionCommunity.initialActiveCommunityId}
+        >
           <CommunityOnboardingProvider enabled={!isCompanionWindow()}>
             <ThemeProvider defaultTheme="buzz">
               <TooltipProvider>