Fix filtered search user autocomplete for gitlab instances that are hosted on a subdirectory

app/assets/javascripts/filtered_search/dropdown_user.js.es6

@@ -8,7 +8,7 @@ require('./filtered_search_dropdown');
       super(droplab, dropdown, input, filter);
       this.config = {
         droplabAjaxFilter: {
-          endpoint: '/autocomplete/users.json',
+          endpoint: `${gon.relative_url_root || ''}/autocomplete/users.json`,
           searchKey: 'search',
           params: {
             per_page: 20,

changelogs/unreleased/27343-autocomplete-post-to-wrong-url-when-not-hosting-in-root.yml

+---
+title: Fix filtered search user autocomplete for gitlab instances that are hosted
+  on a subdirectory
+merge_request: 8891
+author:

spec/javascripts/filtered_search/dropdown_user_spec.js.es6

@@ -36,5 +36,40 @@ require('~/filtered_search/dropdown_user');
         expect(dropdownUser.getSearchInput()).toBe('larry boy');
       });
     });
+
+    describe('config droplabAjaxFilter\'s endpoint', () => {
+      beforeEach(() => {
+        spyOn(gl.FilteredSearchDropdown.prototype, 'constructor').and.callFake(() => {});
+        spyOn(gl.DropdownUser.prototype, 'getProjectId').and.callFake(() => {});
+      });
+
+      it('should return endpoint', () => {
+        window.gon = {
+          relative_url_root: '',
+        };
+        const dropdown = new gl.DropdownUser();
+
+        expect(dropdown.config.droplabAjaxFilter.endpoint).toBe('/autocomplete/users.json');
+      });
+
+      it('should return endpoint when relative_url_root is undefined', () => {
+        const dropdown = new gl.DropdownUser();
+
+        expect(dropdown.config.droplabAjaxFilter.endpoint).toBe('/autocomplete/users.json');
+      });
+
+      it('should return endpoint with relative url when available', () => {
+        window.gon = {
+          relative_url_root: '/gitlab_directory',
+        };
+        const dropdown = new gl.DropdownUser();
+
+        expect(dropdown.config.droplabAjaxFilter.endpoint).toBe('/gitlab_directory/autocomplete/users.json');
+      });
+
+      afterEach(() => {
+        window.gon = {};
+      });
+    });
   });
 })();

spec/javascripts/project_title_spec.js

@@ -9,19 +9,20 @@ require('~/project_select');
 require('~/project');
 (function() {
-  window.gon || (window.gon = {});
-
-  window.gon.api_version = 'v3';
-
   describe('Project Title', function() {
     preloadFixtures('static/project_title.html.raw');
     loadJSONFixtures('projects.json');
     beforeEach(function() {
       loadFixtures('static/project_title.html.raw');
+
+      window.gon = {};
+      window.gon.api_version = 'v3';
+
       return this.project = new Project();
     });
-    return describe('project list', function() {
+
+    describe('project list', function() {
       var fakeAjaxResponse = function fakeAjaxResponse(req) {
         var d;
         expect(req.url).toBe('/api/v3/projects.json?simple=true');
@@ -48,5 +49,9 @@ require('~/project');
         return expect($('.header-content').hasClass('open')).toBe(false);
       });
     });
+
+    afterEach(() => {
+      window.gon = {};
+    });
   });
 }).call(this);

spec/javascripts/search_autocomplete_spec.js

@@ -14,11 +14,6 @@ require('vendor/fuzzaldrin-plus');
   userId = 1;
-  window.gon || (window.gon = {});
-
-  window.gon.current_user_id = userId;
-  window.gon.current_username = userName;
-
   dashboardIssuesPath = '/dashboard/issues';
   dashboardMRsPath = '/dashboard/merge_requests';
@@ -117,6 +112,16 @@ require('vendor/fuzzaldrin-plus');
       widget = new gl.SearchAutocomplete;
       // Prevent turbolinks from triggering within gl_dropdown
       spyOn(window.gl.utils, 'visitUrl').and.returnValue(true);
+
+      window.gon = {};
+      window.gon.current_user_id = userId;
+      window.gon.current_username = userName;
+
+      return widget = new gl.SearchAutocomplete;
+    });
+
+    afterEach(function() {
+      window.gon = {};
     });
     it('should show Dashboard specific dropdown menu', function() {
       var list;