composebox_typeahead: Hide user groups from mention typeahead.

This commit adds code to hide the user groups which a user is
not allowed to mention from the mention typeahead.

Fixes a part of #25927.

web/src/composebox_typeahead.js

@@ -424,6 +424,7 @@ export function filter_and_sort_mentions(is_silent, query, opts) {
     opts = {
         want_broadcast: !is_silent,
         filter_pills: false,
+        filter_groups: !is_silent,
         ...opts,
     };
     return get_person_suggestions(query, opts);
@@ -460,7 +461,12 @@ export function get_person_suggestions(query, opts) {
         return persons.filter((item) => query_matches_person(query, item));
     }
 
-    const groups = user_groups.get_realm_user_groups();
+    let groups;
+    if (opts.filter_groups) {
+        groups = user_groups.get_user_groups_allowed_to_mention();
+    } else {
+        groups = user_groups.get_realm_user_groups();
+    }
 
     const filtered_groups = groups.filter((item) => query_matches_name(query, item));
 

web/src/user_groups.ts

@@ -1,6 +1,7 @@
 import * as blueslip from "./blueslip";
 import {FoldDict} from "./fold_dict";
 import * as group_permission_settings from "./group_permission_settings";
+import {page_params} from "./page_params";
 import * as settings_config from "./settings_config";
 import type {User, UserGroupUpdateEvent} from "./types";
 
@@ -88,6 +89,21 @@ export function get_realm_user_groups(): UserGroup[] {
     return user_groups.filter((group) => !group.is_system_group);
 }
 
+export function get_user_groups_allowed_to_mention(): UserGroup[] {
+    if (page_params.user_id === undefined) {
+        return [];
+    }
+
+    const user_groups = get_realm_user_groups();
+    return user_groups.filter((group) => {
+        const can_mention_group_id = group.can_mention_group_id;
+        return (
+            page_params.user_id !== undefined &&
+            is_user_in_group(can_mention_group_id, page_params.user_id)
+        );
+    });
+}
+
 export function is_direct_member_of(user_id: number, user_group_id: number): boolean {
     const user_group = user_group_by_id_dict.get(user_group_id);
     if (user_group === undefined) {

web/tests/composebox_typeahead.test.js

@@ -7,7 +7,7 @@ const {mock_banners} = require("./lib/compose_banner");
 const {mock_esm, set_global, with_overrides, zrequire} = require("./lib/namespace");
 const {run_test} = require("./lib/test");
 const $ = require("./lib/zjquery");
-const {user_settings} = require("./lib/zpage_params");
+const {page_params, user_settings} = require("./lib/zpage_params");
 
 const noop = () => {};
 
@@ -324,7 +324,7 @@ const hamletcharacters = {
     description: "Characters of Hamlet",
     members: new Set([100, 104]),
     is_system_group: false,
-    direct_subgroup_ids: new Set([10, 11]),
+    direct_subgroup_ids: new Set([]),
     can_mention_group_id: 2,
 };
 
@@ -332,9 +332,9 @@ const backend = {
     name: "Backend",
     id: 2,
     description: "Backend team",
-    members: new Set([]),
+    members: new Set([101]),
     is_system_group: false,
-    direct_subgroup_ids: new Set([]),
+    direct_subgroup_ids: new Set([1]),
     can_mention_group_id: 1,
 };
 
@@ -342,7 +342,7 @@ const call_center = {
     name: "Call Center",
     id: 3,
     description: "folks working in support",
-    members: new Set([]),
+    members: new Set([102]),
     is_system_group: false,
     direct_subgroup_ids: new Set([]),
     can_mention_group_id: 2,
@@ -1533,19 +1533,39 @@ test("content_highlighter", ({override_rewire}) => {
 test("filter_and_sort_mentions (normal)", () => {
     compose_state.set_message_type("stream");
     const is_silent = false;
-
-    const suggestions = ct.filter_and_sort_mentions(is_silent, "al");
+    page_params.user_id = 101;
+    let suggestions = ct.filter_and_sort_mentions(is_silent, "al");
 
     const mention_all = ct.broadcast_mentions()[0];
     assert.deepEqual(suggestions, [mention_all, ali, alice, hal, call_center]);
+
+    // call_center group is shown in typeahead even when user is member of
+    // one of the subgroups of can_mention_group.
+    page_params.user_id = 104;
+    suggestions = ct.filter_and_sort_mentions(is_silent, "al");
+    assert.deepEqual(suggestions, [mention_all, ali, alice, hal, call_center]);
+
+    // call_center group is not shown in typeahead when user is neither
+    // a direct member of can_mention_group nor a member of any of its
+    // recursive subgroups.
+    page_params.user_id = 102;
+    suggestions = ct.filter_and_sort_mentions(is_silent, "al");
+    assert.deepEqual(suggestions, [mention_all, ali, alice, hal]);
 });
 
 test("filter_and_sort_mentions (silent)", () => {
     const is_silent = true;
 
-    const suggestions = ct.filter_and_sort_mentions(is_silent, "al");
+    let suggestions = ct.filter_and_sort_mentions(is_silent, "al");
 
     assert.deepEqual(suggestions, [ali, alice, hal, call_center]);
+
+    // call_center group is shown in typeahead irrespective of whether
+    // user is member of can_mention_group or its subgroups for a
+    // silent mention.
+    page_params.user_id = 102;
+    suggestions = ct.filter_and_sort_mentions(is_silent, "al");
+    assert.deepEqual(suggestions, [ali, alice, hal, call_center]);
 });
 
 test("typeahead_results", () => {
@@ -1654,7 +1674,7 @@ test("typeahead_results", () => {
     // Earlier user group and stream mentions were autocompleted by their
     // description too. This is now removed as it often led to unexpected
     // behaviour, and did not have any great discoverability advantage.
-
+    page_params.user_id = 101;
     // Autocomplete user group mentions by group name.
     assert_mentions_matches("hamletchar", [hamletcharacters]);