model: Factor out new RESET_ACCOUNT_DATA action

As Greg proposed in #4446, so the pattern of consistently clearing
data on all ways of leaving an account gets maintained naturally:

(except we chose the name RESET_ACCOUNT_DATA instead of
CLEAR_ACCOUNT_DATA)

> * I think it'd be a useful refactor to consolidate one action type
>   like `CLEAR_ACCOUNT_DATA`.
>   * The action creators for these three (in `accountActions.js`) can
>     dispatch that first, then also a `LOGOUT` etc.
>   * Almost all the reducers would respond only to the
>     `CLEAR_ACCOUNT_DATA`.
>   * There are a couple of exceptions, like `accountReducers` and
>     `sessionReducers`, that actually want to treat the three cases
>     differently. Those would be the only ones to continue responding
>     to `LOGOUT` etc.; and they'd stand out better as a result.
>   * Then there are further changes we might make to those, but
>     that'll be easier to see after that.

Fixes: #4446

Author: chrisbobbe

src/__tests__/lib/exampleData.js

@@ -25,6 +25,7 @@ import { CreateWebPublicStreamPolicy, EmailAddressVisibility } from '../../api/p
 import type {
   AccountSwitchAction,
   LoginSuccessAction,
+  ResetAccountDataAction,
   RegisterCompleteAction,
   MessageFetchStartAction,
   MessageFetchCompleteAction,
@@ -44,6 +45,7 @@ import { ZulipVersion } from '../../utils/zulipVersion';
 import {
   ACCOUNT_SWITCH,
   LOGIN_SUCCESS,
+  RESET_ACCOUNT_DATA,
   REGISTER_COMPLETE,
   EVENT_NEW_MESSAGE,
   MESSAGE_FETCH_START,
@@ -705,6 +707,7 @@ export const action = Object.freeze({
     email: selfAccount.email,
     apiKey: selfAccount.apiKey,
   }): LoginSuccessAction),
+  reset_account_data: (deepFreeze({ type: RESET_ACCOUNT_DATA }): ResetAccountDataAction),
 
   /**
    * A minimal well-typed REGISTER_COMPLETE action from a recent server.

src/account/accountActions.js

@@ -11,6 +11,7 @@ import { registerAndStartPolling } from '../events/eventActions';
 import { resetToMainTabs } from '../nav/navActions';
 import { sendOutbox } from '../outbox/outboxActions';
 import { initNotifications } from '../notification/notifTokens';
+import { resetAccountData } from './logoutActions';
 
 export const dismissServerPushSetupNotice = (): PerAccountAction => ({
   type: DISMISS_SERVER_PUSH_SETUP_NOTICE,
@@ -30,6 +31,13 @@ export const accountSwitch =
   (index: number): GlobalThunkAction<Promise<void>> =>
   async (dispatch, getState, { activeAccountDispatch }) => {
     NavigationService.dispatch(resetToMainTabs());
+
+    // Clear out the space we use for the active account's server data, to
+    // make way for a new active account.
+    // TODO(#5006): When each account has its own space to hold server data,
+    //   we won't have to do this.
+    activeAccountDispatch(resetAccountData());
+
     dispatch(accountSwitchPlain(index));
 
     // Now dispatch some actions on the new, post-switch active account.
@@ -60,6 +68,14 @@ export const loginSuccess =
   (realm: URL, email: string, apiKey: string): GlobalThunkAction<Promise<void>> =>
   async (dispatch, getState, { activeAccountDispatch }) => {
     NavigationService.dispatch(resetToMainTabs());
+
+    // In case there's already an active account, clear out the space we use
+    // for the active account's server data, to make way for a new active
+    // account.
+    // TODO(#5006): When each account has its own space to hold server data,
+    //   we won't have to do this.
+    activeAccountDispatch(resetAccountData());
+
     dispatch(loginSuccessPlain(realm, email, apiKey));
 
     // Now dispatch some actions on the new, post-login active account.

src/account/logoutActions.js

@@ -1,9 +1,17 @@
 /* @flow strict-local */
 import * as NavigationService from '../nav/NavigationService';
-import type { AllAccountsAction, ThunkAction } from '../types';
-import { LOGOUT } from '../actionConstants';
+import type { PerAccountAction, AllAccountsAction, ThunkAction } from '../types';
+import { LOGOUT, RESET_ACCOUNT_DATA } from '../actionConstants';
 import { resetToAccountPicker } from '../nav/navActions';
 
+/**
+ * Reset per-account server data and some client-side data (drafts/outbox).
+ */
+// In this file just to prevent import cycles.
+export const resetAccountData = (): PerAccountAction => ({
+  type: RESET_ACCOUNT_DATA,
+});
+
 const logoutPlain = (): AllAccountsAction => ({
   type: LOGOUT,
 });
@@ -14,5 +22,6 @@ const logoutPlain = (): AllAccountsAction => ({
 // In its own file just to prevent import cycles.
 export const logout = (): ThunkAction<Promise<void>> => async (dispatch, getState) => {
   NavigationService.dispatch(resetToAccountPicker());
+  dispatch(resetAccountData());
   dispatch(logoutPlain());
 };

src/actionConstants.js

@@ -15,6 +15,8 @@ export const REGISTER_START: 'REGISTER_START' = 'REGISTER_START';
 export const REGISTER_ABORT: 'REGISTER_ABORT' = 'REGISTER_ABORT';
 export const REGISTER_COMPLETE: 'REGISTER_COMPLETE' = 'REGISTER_COMPLETE';
 
+export const RESET_ACCOUNT_DATA: 'RESET_ACCOUNT_DATA' = 'RESET_ACCOUNT_DATA';
+
 export const REFRESH_SERVER_EMOJI_DATA: 'REFRESH_SERVER_EMOJI_DATA' = 'REFRESH_SERVER_EMOJI_DATA';
 
 export const DISMISS_SERVER_PUSH_SETUP_NOTICE: 'DISMISS_SERVER_PUSH_SETUP_NOTICE' =

src/actionTypes.js

@@ -10,6 +10,7 @@ import {
   ACCOUNT_REMOVE,
   LOGIN_SUCCESS,
   LOGOUT,
+  RESET_ACCOUNT_DATA,
   DISMISS_SERVER_PUSH_SETUP_NOTICE,
   GOT_PUSH_TOKEN,
   UNACK_PUSH_TOKEN,
@@ -170,6 +171,10 @@ type LogoutAction = $ReadOnly<{|
   type: typeof LOGOUT,
 |}>;
 
+export type ResetAccountDataAction = $ReadOnly<{|
+  type: typeof RESET_ACCOUNT_DATA,
+|}>;
+
 type DismissServerPushSetupNoticeAction = $ReadOnly<{|
   type: typeof DISMISS_SERVER_PUSH_SETUP_NOTICE,
   date: Date,
@@ -646,6 +651,7 @@ export type PerAccountAction =
   // The grouping here is completely arbitrary; don't worry about it.
   | EventAction
   | LoadingAction
+  | ResetAccountDataAction
   | RefreshServerEmojiDataAction
   | MessageAction
   | OutboxAction
@@ -739,6 +745,7 @@ export type DispatchableWithoutAccountAction =
 /** True just if the action is a PerAccountApplicableAction. */
 export function isPerAccountApplicableAction(action: Action): boolean {
   switch (action.type) {
+    case RESET_ACCOUNT_DATA:
     case EVENT:
     case EVENT_ALERT_WORDS:
     case EVENT_MESSAGE_DELETE:

src/alertWords/alertWordsReducer.js

@@ -1,12 +1,6 @@
 /* @flow strict-local */
 import type { AlertWordsState, PerAccountApplicableAction } from '../types';
-import {
-  REGISTER_COMPLETE,
-  EVENT_ALERT_WORDS,
-  ACCOUNT_SWITCH,
-  LOGOUT,
-  LOGIN_SUCCESS,
-} from '../actionConstants';
+import { REGISTER_COMPLETE, EVENT_ALERT_WORDS, RESET_ACCOUNT_DATA } from '../actionConstants';
 import { NULL_ARRAY } from '../nullObjects';
 
 const initialState = NULL_ARRAY;
@@ -16,9 +10,7 @@ export default (
   action: PerAccountApplicableAction,
 ): AlertWordsState => {
   switch (action.type) {
-    case LOGOUT:
-    case ACCOUNT_SWITCH:
-    case LOGIN_SUCCESS:
+    case RESET_ACCOUNT_DATA:
       return initialState;
 
     case REGISTER_COMPLETE:

src/caughtup/caughtUpReducer.js

@@ -2,14 +2,12 @@
 import type { CaughtUpState, PerAccountApplicableAction } from '../types';
 import {
   REGISTER_COMPLETE,
-  LOGOUT,
-  LOGIN_SUCCESS,
-  ACCOUNT_SWITCH,
   MESSAGE_FETCH_START,
   MESSAGE_FETCH_ERROR,
   MESSAGE_FETCH_COMPLETE,
   EVENT_UPDATE_MESSAGE,
   EVENT_UPDATE_MESSAGE_FLAGS,
+  RESET_ACCOUNT_DATA,
 } from '../actionConstants';
 import { NULL_OBJECT } from '../nullObjects';
 import { DEFAULT_CAUGHTUP } from './caughtUpSelectors';
@@ -35,9 +33,7 @@ export default (
 ): CaughtUpState => {
   switch (action.type) {
     case REGISTER_COMPLETE:
-    case LOGOUT:
-    case LOGIN_SUCCESS:
-    case ACCOUNT_SWITCH:
+    case RESET_ACCOUNT_DATA:
       return initialState;
 
     case MESSAGE_FETCH_START: {

src/chat/__tests__/flagsReducer-test.js

@@ -4,7 +4,7 @@ import deepFreeze from 'deep-freeze';
 
 import * as eg from '../../__tests__/lib/exampleData';
 import flagsReducer from '../flagsReducer';
-import { EVENT_UPDATE_MESSAGE_FLAGS, ACCOUNT_SWITCH } from '../../actionConstants';
+import { EVENT_UPDATE_MESSAGE_FLAGS } from '../../actionConstants';
 
 describe('flagsReducer', () => {
   describe('MESSAGE_FETCH_COMPLETE', () => {
@@ -270,7 +270,7 @@ describe('flagsReducer', () => {
     });
   });
 
-  describe('ACCOUNT_SWITCH', () => {
+  describe('RESET_ACCOUNT_DATA', () => {
     test('resets to initial state', () => {
       const message = eg.streamMessage();
 
@@ -284,7 +284,7 @@ describe('flagsReducer', () => {
         historical: { [message.id]: true },
       });
 
-      expect(flagsReducer(prevState, deepFreeze({ type: ACCOUNT_SWITCH, index: 2 }))).toEqual(
+      expect(flagsReducer(prevState, eg.action.reset_account_data)).toEqual(
         eg.baseReduxState.flags,
       );
     });

src/chat/fetchingReducer.js

@@ -1,12 +1,10 @@
 /* @flow strict-local */
 import type { FetchingState, PerAccountApplicableAction } from '../types';
 import {
-  LOGOUT,
-  LOGIN_SUCCESS,
-  ACCOUNT_SWITCH,
   MESSAGE_FETCH_START,
   MESSAGE_FETCH_ERROR,
   MESSAGE_FETCH_COMPLETE,
+  RESET_ACCOUNT_DATA,
 } from '../actionConstants';
 import { NULL_OBJECT } from '../nullObjects';
 import { DEFAULT_FETCHING } from './fetchingSelectors';
@@ -68,9 +66,7 @@ export default (
   action: PerAccountApplicableAction,
 ): FetchingState => {
   switch (action.type) {
-    case LOGOUT:
-    case LOGIN_SUCCESS:
-    case ACCOUNT_SWITCH:
+    case RESET_ACCOUNT_DATA:
       return initialState;
 
     case MESSAGE_FETCH_START:

src/chat/flagsReducer.js

@@ -8,9 +8,7 @@ import {
   MESSAGE_FETCH_COMPLETE,
   EVENT_NEW_MESSAGE,
   EVENT_UPDATE_MESSAGE_FLAGS,
-  LOGOUT,
-  LOGIN_SUCCESS,
-  ACCOUNT_SWITCH,
+  RESET_ACCOUNT_DATA,
 } from '../actionConstants';
 import { deeperMerge } from '../utils/misc';
 import type { UserMessageFlag } from '../api/modelTypes';
@@ -134,9 +132,7 @@ export default (
 ): FlagsState => {
   switch (action.type) {
     case REGISTER_COMPLETE:
-    case LOGOUT:
-    case LOGIN_SUCCESS:
-    case ACCOUNT_SWITCH:
+    case RESET_ACCOUNT_DATA:
       return initialState;
 
     case MESSAGE_FETCH_COMPLETE: