From be033394b18da20f09c8cd98bf1a0e89e68a8c30 Mon Sep 17 00:00:00 2001
From: evykassirer <evy@zulip.com>
Date: Thu, 16 Nov 2023 16:32:35 -0800
Subject: [PATCH] stream events: Rebuild buddy list when user is subscribed or
 unsubscribed.

---
 web/src/stream_events.js        |  7 +++++++
 web/tests/stream_events.test.js | 19 ++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/web/src/stream_events.js b/web/src/stream_events.js
index d926263b24..8932a3209c 100644
--- a/web/src/stream_events.js
+++ b/web/src/stream_events.js
@@ -1,5 +1,6 @@
 import $ from "jquery";
 
+import * as activity_ui from "./activity_ui";
 import * as blueslip from "./blueslip";
 import * as color_data from "./color_data";
 import * as compose_recipient from "./compose_recipient";
@@ -146,6 +147,7 @@ export function mark_subscribed(sub, subscribers, color) {
 
     if (narrow_state.is_for_stream_id(sub.stream_id)) {
         message_lists.current.update_trailing_bookend();
+        activity_ui.build_user_sidebar();
     }
 
     // The new stream in sidebar might need its unread counts
@@ -181,6 +183,8 @@ export function mark_unsubscribed(sub) {
         // This update would likely be better implemented by having it
         // disappear whenever no unread messages remain.
         unread_ui.hide_unread_banner();
+
+        activity_ui.build_user_sidebar();
     }
 
     // Unread messages in the now-unsubscribe stream need to be
@@ -209,4 +213,7 @@ export function process_subscriber_update(user_ids, stream_ids) {
         stream_settings_ui.update_subscribers_ui(sub);
     }
     user_profile.update_user_profile_streams_list_for_users(user_ids);
+    if (stream_ids.includes(narrow_state.stream_id())) {
+        activity_ui.build_user_sidebar();
+    }
 }
diff --git a/web/tests/stream_events.test.js b/web/tests/stream_events.test.js
index f6bd013eea..be0e07e5e5 100644
--- a/web/tests/stream_events.test.js
+++ b/web/tests/stream_events.test.js
@@ -36,6 +36,8 @@ mock_esm("../src/overlays", {
 const user_profile = mock_esm("../src/user_profile");
 
 const {Filter} = zrequire("../src/filter");
+const activity_ui = zrequire("activity_ui");
+const {buddy_list} = zrequire("buddy_list");
 const narrow_state = zrequire("narrow_state");
 const peer_data = zrequire("peer_data");
 const people = zrequire("people");
@@ -285,6 +287,8 @@ test("marked_subscribed (normal)", ({override}) => {
     const sub = {...frontend};
     stream_data.add_sub(sub);
     override(stream_color_events, "update_stream_color", noop);
+    override(buddy_list, "populate", noop);
+    activity_ui.set_cursor_and_filter();
 
     narrow_to_frontend();
 
@@ -421,6 +425,7 @@ test("mark_unsubscribed (render_title_area)", ({override}) => {
     override(unread_ui, "update_unread_counts", noop);
     override(unread_ui, "hide_unread_banner", noop);
     override(user_profile, "update_user_profile_streams_list_for_users", noop);
+    override(buddy_list, "populate", noop);
 
     $("#streams_overlay_container .stream-row:not(.notdisplayed)").length = 0;
 
@@ -449,10 +454,14 @@ test("remove_deactivated_user_from_all_streams", () => {
     assert.equal(subs_stub.num_calls, 1);
 });
 
-test("process_subscriber_update", ({override}) => {
+test("process_subscriber_update", ({override, override_rewire}) => {
     const subsStub = make_stub();
     stream_settings_ui.update_subscribers_ui = subsStub.f;
 
+    let build_user_sidebar_called = false;
+    override_rewire(activity_ui, "build_user_sidebar", () => {
+        build_user_sidebar_called = true;
+    });
     override(user_profile, "update_user_profile_streams_list_for_users", noop);
     // Sample user IDs
     const userIds = [104, 2, 3];
@@ -464,4 +473,12 @@ test("process_subscriber_update", ({override}) => {
 
     // Assert that update_subscribers_ui is called for each stream ID
     assert.equal(subsStub.num_calls, streamIds.length);
+
+    assert.ok(!build_user_sidebar_called);
+
+    // For a stream the user is currently viewing, we rebuild the user sidebar
+    // when someone subscribes to that stream.
+    override_rewire(narrow_state, "stream_id", () => 1);
+    stream_events.process_subscriber_update(userIds, streamIds);
+    assert.ok(build_user_sidebar_called);
 });