Remove File-By-File preference cookie

Since we now use a database setting to store the user's preference,
the cookie is redundant and can lead to some minor broken edge-cases.

Removing this cookie can also lead to a small annoyance in some
edge cases (see link below), but it's easily - and permanently -
remediated by toggling the checkbox again (or changing the user
preference in the settings page directly).

https://gitlab.com/gitlab-org/gitlab/-/issues/327162#note_549832248

Changelog: changed

app/assets/javascripts/diffs/components/app.vue

@@ -46,7 +46,6 @@ import {
 import diffsEventHub from '../event_hub';
 import { reviewStatuses } from '../utils/file_reviews';
 import { diffsApp } from '../utils/performance';
-import { fileByFile } from '../utils/preferences';
 import { queueRedisHllEvents } from '../utils/queue_events';
 import CollapsedFilesWarning from './collapsed_files_warning.vue';
 import CommitWidget from './commit_widget.vue';
@@ -331,7 +330,7 @@ export default {
       projectPath: this.projectPath,
       dismissEndpoint: this.dismissEndpoint,
       showSuggestPopover: this.showSuggestPopover,
-      viewDiffsFileByFile: fileByFile(this.fileByFileUserPreference),
+      viewDiffsFileByFile: this.fileByFileUserPreference || false,
       defaultSuggestionCommitMessage: this.defaultSuggestionCommitMessage,
       mrReviews: this.rehydratedMrReviews,
     });

app/assets/javascripts/diffs/constants.js

@@ -72,11 +72,6 @@ export const ALERT_COLLAPSED_FILES = 'collapsed';
 export const DIFF_FILE_AUTOMATIC_COLLAPSE = 'automatic';
 export const DIFF_FILE_MANUAL_COLLAPSE = 'manual';
 
-// Diff view single file mode
-export const DIFF_FILE_BY_FILE_COOKIE_NAME = 'fileViewMode';
-export const DIFF_VIEW_FILE_BY_FILE = 'single';
-export const DIFF_VIEW_ALL_FILES = 'all';
-
 // State machine states
 export const STATE_IDLING = 'idle';
 export const STATE_LOADING = 'loading';

app/assets/javascripts/diffs/store/actions.js

@@ -29,9 +29,6 @@ import {
   EVT_PERF_MARK_FILE_TREE_START,
   EVT_PERF_MARK_FILE_TREE_END,
   EVT_PERF_MARK_DIFF_FILES_START,
-  DIFF_VIEW_FILE_BY_FILE,
-  DIFF_VIEW_ALL_FILES,
-  DIFF_FILE_BY_FILE_COOKIE_NAME,
   TRACKING_CLICK_DIFF_VIEW_SETTING,
   TRACKING_DIFF_VIEW_INLINE,
   TRACKING_DIFF_VIEW_PARALLEL,
@@ -816,9 +813,7 @@ export const navigateToDiffFileIndex = ({ commit, state }, index) => {
 };
 
 export const setFileByFile = ({ state, commit }, { fileByFile }) => {
-  const fileViewMode = fileByFile ? DIFF_VIEW_FILE_BY_FILE : DIFF_VIEW_ALL_FILES;
   commit(types.SET_FILE_BY_FILE, fileByFile);
-  Cookies.set(DIFF_FILE_BY_FILE_COOKIE_NAME, fileViewMode);
 
   if (window.gon?.features?.diffSettingsUsageData) {
     const events = [TRACKING_CLICK_SINGLE_FILE_SETTING];

app/assets/javascripts/diffs/store/modules/diff_state.js

@@ -2,8 +2,6 @@ import Cookies from 'js-cookie';
 import { getParameterValues } from '~/lib/utils/url_utility';
 import { INLINE_DIFF_VIEW_TYPE, DIFF_VIEW_COOKIE_NAME } from '../../constants';
 
-import { fileByFile } from '../../utils/preferences';
-
 const getViewTypeFromQueryString = () => getParameterValues('view')[0];
 
 const viewTypeFromCookie = Cookies.get(DIFF_VIEW_COOKIE_NAME);
@@ -36,7 +34,7 @@ export default () => ({
   highlightedRow: null,
   renderTreeList: true,
   showWhitespace: true,
-  viewDiffsFileByFile: fileByFile(),
+  viewDiffsFileByFile: false,
   fileFinderVisible: false,
   dismissEndpoint: '',
   showSuggestPopover: true,

app/assets/javascripts/diffs/utils/preferences.js

-import Cookies from 'js-cookie';
-import { DIFF_FILE_BY_FILE_COOKIE_NAME, DIFF_VIEW_FILE_BY_FILE } from '../constants';
-
-export function fileByFile(pref = false) {
-  const cookie = Cookies.get(DIFF_FILE_BY_FILE_COOKIE_NAME);
-
-  // use the cookie first, if it exists
-  if (cookie) {
-    return cookie === DIFF_VIEW_FILE_BY_FILE;
-  }
-
-  return pref;
-}

spec/frontend/diffs/utils/preferences_spec.js

-import Cookies from 'js-cookie';
-import {
-  DIFF_FILE_BY_FILE_COOKIE_NAME,
-  DIFF_VIEW_FILE_BY_FILE,
-  DIFF_VIEW_ALL_FILES,
-} from '~/diffs/constants';
-import { fileByFile } from '~/diffs/utils/preferences';
-
-describe('diffs preferences', () => {
-  describe('fileByFile', () => {
-    afterEach(() => {
-      Cookies.remove(DIFF_FILE_BY_FILE_COOKIE_NAME);
-    });
-
-    it.each`
-      result   | preference | cookie
-      ${true}  | ${false}   | ${DIFF_VIEW_FILE_BY_FILE}
-      ${false} | ${true}    | ${DIFF_VIEW_ALL_FILES}
-      ${true}  | ${false}   | ${DIFF_VIEW_FILE_BY_FILE}
-      ${false} | ${true}    | ${DIFF_VIEW_ALL_FILES}
-      ${false} | ${false}   | ${DIFF_VIEW_ALL_FILES}
-      ${true}  | ${true}    | ${DIFF_VIEW_FILE_BY_FILE}
-    `(
-      'should return $result when { preference: $preference, cookie: $cookie }',
-      ({ result, preference, cookie }) => {
-        Cookies.set(DIFF_FILE_BY_FILE_COOKIE_NAME, cookie);
-
-        expect(fileByFile(preference)).toBe(result);
-      },
-    );
-  });
-});