shah-harshit · Oct 29, 2026 · Oct 28, 2026 · Oct 28, 2026 · Oct 28, 2026 · Oct 28, 2026
@@ -44,6 +44,7 @@ import PermissionPlaceholder from '../common/EmptyPlaceholder/PermissionPlacehol
 import { UserTeamSelectableList } from '../common/UserTeamSelectableList/UserTeamSelectableList.component';
 import { IncidentManagerProps } from './IncidentManager.interface';
 import IncidentManagerTable from './IncidentManagerTable.component';
+import { useIncidentAssignees } from './useIncidentFilterOptions';
 import { useIncidentManagerListPage } from './useIncidentManagerListPage';
 
 const toSelection = (value?: string) => (value ? [value] : []);
@@ -81,6 +82,7 @@ const IncidentManager = ({
 
   const captionId = useId();
   const queryClient = useQueryClient();
+  const assignees = useIncidentAssignees();
   const [isTestCasePickerOpen, setIsTestCasePickerOpen] = useState(false);
   const [testCaseSearch, setTestCaseSearch] = useState('');
   const debouncedSearch = useDebouncedValue(testCaseSearch, 300);
@@ -222,6 +224,7 @@ const IncidentManager = ({
           <UserTeamSelectableList
             hasPermission
             label={t('label.assignee')}
+            options={assignees}
             owner={selectedAssignee ? [selectedAssignee] : []}
             onUpdate={onAssigneeFilterUpdate}>
             <TriggerButton

@@ -15,7 +15,7 @@
 import React, { act } from 'react';
 import { usePermissionProvider } from '../../context/PermissionProvider/PermissionProvider';
 import { Table } from '../../generated/entity/data/table';
 import { TestCasePageTabs } from '../../pages/IncidentManager/IncidentManager.interface';
 import { getListTestCaseIncidentStatusFromSearch } from '../../rest/incidentManagerAPI';
 import {
  renderWithQueryClient as render,
@@ -285,6 +285,37 @@
   getUserAndTeamSearch: jest
     .fn()
     .mockImplementation(() => Promise.resolve({ data: [] })),
+  postAggregateFieldOptions: jest.fn().mockResolvedValue({
+    data: {
+      aggregations: {
+        'sterms#testCaseResolutionStatusDetails.assignee.id': {
+          buckets: [
+            {
+              'top_hits#top': {
+                hits: {
+                  hits: [
+                    {
+                      _source: {
+                        testCaseResolutionStatusDetails: {
+                          assignee: {
+                            id: 'user-1',
+                            type: 'user',
+                            name: 'user1',
+                            displayName: 'User One',
+                            deleted: false,
+                          },
+                        },
+                      },
+                    },
+                  ],
+                },
+              },
+            },
+          ],
+        },
+      },
+    },
+  }),
 }));
 jest.mock('../../rest/userAPI', () => ({
   getUsers: jest.fn().mockImplementation(() => Promise.resolve({ data: [] })),
@@ -535,6 +566,43 @@
     expect(screen.queryByTestId('select-owner-tabs')).not.toBeInTheDocument();
   });
 
+  it('offers only the users and teams some incident is assigned to', async () => {
+    const mockSearchQuery = require('../../rest/searchAPI').searchQuery;
+    await act(async () => {
+      render(<IncidentManager />);
+    });
+    await act(async () => {
+      fireEvent.click(screen.getByTestId('select-assignee'));
+    });
+
+    expect(
+      screen.getByRole('tab', { name: /label.team-plural/ })
+    ).toHaveTextContent('0');
+    expect(
+      screen.getByRole('tab', { name: /label.user-plural/ })
+    ).toHaveTextContent('1');
+
+    await act(async () => {
+      fireEvent.click(screen.getByRole('tab', { name: /label.user-plural/ }));
+    });
+
+    expect(
+      within(screen.getByTestId('owner-select-users-panel')).getAllByTestId(
+        'owner-option'
+      )
+    ).toHaveLength(1);
+    expect(screen.getByTestId('owner-select-users-panel')).toHaveTextContent(
+      'User One'
+    );
+    // The picker lists the assignees it was given, not the user/team indexes.
+    expect(mockSearchQuery).not.toHaveBeenCalledWith(
+      expect.objectContaining({ searchIndex: 'user' })
+    );
+    expect(mockSearchQuery).not.toHaveBeenCalledWith(
+      expect.objectContaining({ searchIndex: 'team' })
+    );
+  });
+
   it('clears a URL-selected assignee after reopening the picker without needing a combobox', async () => {
     const navigate = jest.fn();
     require('react-router-dom').useNavigate.mockReturnValue(navigate);

@@ -10,19 +10,100 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
+import { useQuery } from '@tanstack/react-query';
+import { sortBy } from 'lodash';
 import { useCallback, useMemo, useState } from 'react';
 import { WILD_CARD_CHAR } from '../../constants/char.constants';
-import { PAGE_SIZE_BASE } from '../../constants/constants';
+import {
+  AGGREGATE_PAGE_SIZE_LARGE,
+  DEFAULT_DOMAIN_VALUE,
+  PAGE_SIZE_BASE,
+} from '../../constants/constants';
 import { SearchIndex } from '../../enums/search.enum';
+import { EntityReference } from '../../generated/entity/type';
+import { SortOrder } from '../../generated/search/aggregationRequest';
+import { useDomainStore } from '../../hooks/useDomainStore';
 import {
   SearchHitBody,
   TestCaseSearchSource,
 } from '../../interface/search.interface';
 import { Option } from '../../pages/TasksPage/TasksPage.interface';
 import { TestCaseIncidentStatusParams } from '../../rest/incidentManagerAPI';
-import { getUserAndTeamSearch } from '../../rest/miscAPI';
+import {
+  getUserAndTeamSearch,
+  postAggregateFieldOptions,
+} from '../../rest/miscAPI';
 import { searchQuery } from '../../rest/searchAPI';
+import { getQueryFilterForDataProducts } from '../../utils/DomainFilterUtils';
 import { getEntityName } from '../../utils/EntityNameUtils';
+import { getAggregations } from '../../utils/ExplorePureUtils';
+
+const ASSIGNEE_FIELD = 'testCaseResolutionStatusDetails.assignee';
+const NO_ASSIGNEES: EntityReference[] = [];
+
+type AssigneeBucket = {
+  'top_hits#top'?: {
+    hits?: {
+      hits?: {
+        _source?: {
+          testCaseResolutionStatusDetails?: { assignee?: EntityReference };
+        };
+      }[];
+    };
+  };
+};
+
+const fetchIncidentAssignees = async (domain?: string) => {
+  const { data } = await postAggregateFieldOptions({
+    index: 'testCaseResolutionStatus',
+    fieldName: `${ASSIGNEE_FIELD}.id`,
+    fieldValue: '',
+    // A terms aggregation cannot page, so read the whole set up to this cap.
+    // Composite aggregation in /search/aggregate if catalogs ever exceed it.
+    size: AGGREGATE_PAGE_SIZE_LARGE,
+    // Incident documents carry no top-level `deleted`, so the default
+    // `deleted: false` term would match none of them.
+    deleted: null as unknown as boolean,
+    query: domain
+      ? JSON.stringify(getQueryFilterForDataProducts(domain))
+      : undefined,
+    // The latest record names the assignee as they are now.
+    sourceFields: [ASSIGNEE_FIELD],
+    topHits: { size: 1, sortField: 'timestamp', sortOrder: SortOrder.Desc },
+  });
+  const buckets = (getAggregations(data.aggregations)[`${ASSIGNEE_FIELD}.id`]
+    ?.buckets ?? []) as AssigneeBucket[];
+
+  const assignees = buckets.reduce<EntityReference[]>((list, bucket) => {
+    const assignee =
+      bucket['top_hits#top']?.hits?.hits?.[0]?._source
+        ?.testCaseResolutionStatusDetails?.assignee;
+
+    return assignee && !assignee.deleted ? [...list, assignee] : list;
+  }, []);
+
+  return sortBy(assignees, (assignee) => getEntityName(assignee).toLowerCase());
+};
+
+/**
+ * The users and teams assigned to at least one incident in the active domain,
+ * read as a terms aggregation over the incident index so they never depend on
+ * the page of incidents on screen. The assignee picker searches and counts
+ * this list itself: sent as a filter, a large set of ids outgrows the URL of
+ * the user/team search. Empty while it loads and when the read fails, so the
+ * picker offers no one rather than everyone.
+ */
+export const useIncidentAssignees = () => {
+  const { activeDomain } = useDomainStore();
+  const domain =
+    activeDomain === DEFAULT_DOMAIN_VALUE ? undefined : activeDomain;
+  const { data = NO_ASSIGNEES } = useQuery({
+    queryKey: ['incident-assignees', domain],
+    queryFn: () => fetchIncidentAssignees(domain),
+  });
+
+  return data;
+};
 
 export interface UseIncidentFilterOptionsProps {
   filters: TestCaseIncidentStatusParams;

@@ -48,6 +48,7 @@
 import { EditIconButton } from '../IconButtons/EditIconButton';
 import { SelectableList } from '../SelectableList/SelectableList.component';
 import { UserSelectDropdownProps } from './UserTeamSelectableList.interface';
+import { getTabCounts, searchOptions } from './UserTeamSelectableList.utils';
 
 export const TeamListItemRenderer = (props: EntityReference) => {
   return (
@@ -74,6 +75,7 @@
   overlayClassName,
   triggerDataTestId = 'edit-owner',
   triggerClassName,
+  options,
 }: UserSelectDropdownProps) => {
   const { t } = useTranslation();
   const triggerRef = useRef<HTMLSpanElement>(null);
@@ -116,6 +118,11 @@
     return EntityType.TEAM;
   }, [owner]);
 
+  // Ids that arrive after the picker opened must re-read the open lists.
+  const optionsKey = options?.map((option) => option.id).join(',');
+
+  const tabCounts = getTabCounts(count, options);
+
   const isMultiUser = multiple.user;
   const isMultiTeam = multiple.team;
 
@@ -129,6 +136,9 @@
   }, [selectedUsers]);
 
   const fetchUserOptions = async (searchText: string, after?: string) => {
+    if (options) {
+      return searchOptions(options, EntityType.USER, searchText);
+    }
     const afterPage = isNaN(Number(after)) ? 1 : Number(after);
     const isInitialPage = !searchText && afterPage <= 1;
 
@@ -172,6 +182,9 @@
   };
 
   const fetchTeamOptions = async (searchText: string, after?: string) => {
+    if (options) {
+      return searchOptions(options, EntityType.TEAM, searchText);
+    }
     const afterPage = isNaN(Number(after)) ? 1 : Number(after);
     const isInitialPage = !searchText && afterPage <= 1;
 
@@ -253,6 +266,9 @@
   };
 
   const getUserCount = async () => {
+    if (options) {
+      return;
+    }
     const res = await searchQuery({
       query: '',
       pageNumber: 1,
@@ -265,6 +281,9 @@
   };
 
   const getTeamCount = async () => {
+    if (options) {
+      return;
+    }
     const res = await searchQuery({
       query: '',
       pageNumber: 1,
@@ -334,7 +353,7 @@

  useEffect(() => {
    init();
  }, [popupVisible]);

  // Flip the mounted flag in a layout effect (not a passive effect) so the
  // false -> true transition — and therefore the forced-open popover — happens
@@ -456,6 +475,7 @@
     <SelectableList
       fetchOptions={fetchUserOptions}
       height={listHeight}
+      key={optionsKey}
       multiSelect={isMultiUser}
       searchBarDataTestId="owner-select-users-search-bar"
       searchPlaceholder={t('label.search-for-type', {
@@ -482,10 +502,10 @@
           selectedKey={activeTab}
           onSelectionChange={(key) => setActiveTab(key as 'teams' | 'users')}>
           <Tabs.List className="tw:px-2 tw:pt-2" size="sm" type="underline">
-            <Tabs.Item badge={count.team} id="teams">
+            <Tabs.Item badge={tabCounts.team} id="teams">
               {t('label.team-plural')}
             </Tabs.Item>
-            <Tabs.Item badge={count.user} id="users">
+            <Tabs.Item badge={tabCounts.user} id="users">
               {t('label.user-plural')}
             </Tabs.Item>
           </Tabs.List>
@@ -494,6 +514,7 @@
               customTagRenderer={TeamListItemRenderer}
               fetchOptions={fetchTeamOptions}
               height={listHeight}
+              key={optionsKey}
               multiSelect={isMultiTeam}
               searchBarDataTestId="owner-select-teams-search-bar"
               searchPlaceholder={t('label.search-for-type', {

@@ -42,4 +42,9 @@ export interface UserSelectDropdownProps {
   triggerDataTestId?: string;
   /** Classes for the span wrapping a `children` trigger. */
   triggerClassName?: string;
+  /**
+   * Offer only these users and teams: the tabs, their counts and the search
+   * work on this list instead of the user and team search indexes.
+   */
+  options?: EntityReference[];
 }