[FIX] OAuth login not working on electron app with temp sessions (#22401)

client/startup/index.ts

@@ -9,6 +9,7 @@ import './routes';
 import './loginViaQuery';
 import './messageTypes';
 import './notifications';
+import './oauth';
 import './readReceipt';
 import './renderMessage';
 import './renderNotification';

client/startup/oauth.ts

@@ -0,0 +1,21 @@
+import { Meteor } from 'meteor/meteor';
+// @ts-ignore #ToDo: Add definitions for meteor/oauth
+import { OAuth } from 'meteor/oauth';
+
+// OAuth._retrieveCredentialSecret is a meteor method modified to also check the global localStorage
+// This was necessary because of the "Forget User Session on Window Close" setting.
+// The setting changes Meteor._localStorage to use the browser's session storage instead, but that doesn't happen on the Oauth's popup code.
+
+Meteor.startup(() => {
+	const meteorOAuthRetrieveCredentialSecret = OAuth._retrieveCredentialSecret;
+	OAuth._retrieveCredentialSecret = (credentialToken: string): string | undefined => {
+		let secret = meteorOAuthRetrieveCredentialSecret.call(OAuth, credentialToken);
+		if (!secret) {
+			const localStorageKey = `${OAuth._storageTokenPrefix}${credentialToken}`;
+			secret = localStorage.getItem(localStorageKey);
+			localStorage.removeItem(localStorageKey);
+		}
+
+		return secret;
+	};
+});