fix(auth): harden WeChat login and explicit identity switching

h5/js/account-client.js

@@ -1,8 +1,9 @@
 /* Browser identity is a random credential, never a fingerprint or a report. */
 window.AccountClient = (function () {
   'use strict';
-  var key = 'juzi.identity.v1', user = null;
-  function read() { try { return localStorage.getItem(key); } catch (_) { return null; } }
+  var key = 'juzi.identity.v1', kindKey = 'juzi.auth.kind.v1', user = null;
+  function read(name) { try { return localStorage.getItem(name || key); } catch (_) { return null; } }
+  function rememberKind() { try { if (user) localStorage.setItem(kindKey, user.kind); } catch (_) {} }
   function request(url, data) {
     return fetch(url, { credentials: 'same-origin', method: data ? 'POST' : 'GET',
       headers: data ? { 'Content-Type': 'application/json' } : {},
@@ -13,13 +14,16 @@ window.AccountClient = (function () {
   function browser(consent) {
     return request('api/auth/browser', { consent: consent, token: read() }).then(function (v) {
       try { localStorage.setItem(key, v.token); } catch (_) { /* session cookie still works */ }
-      user = v.user; return v;
+      user = v.user; rememberKind(); return v;
     });
   }
-  function init() {
+  function init(options) {
     return request('api/auth/session').then(function (v) {
       user = v.user;
-      if (!user && read()) return browser(true).catch(function (e) {
+      rememberKind();
+      // A missing WeChat session is not permission to switch to a browser account.
+      // OAuth returns must also stay explicit when its cookie was not retained.
+      if (!user && !(options && options.restoreBrowser === false) && read(kindKey) !== 'wechat' && read()) return browser(true).catch(function (e) {
         // Do not replace an existing credential on a transient server/network error.
         if (/身份已失效/.test(e.message)) { try { localStorage.removeItem(key); } catch (_) {} }
         throw e;