Fix Current User

* Add test case to showcase issue
* Update User and App to handle persisting the user on new App instances

integration-tests/tests/src/tests/sync/user.ts

@@ -23,7 +23,7 @@ import {
   randomVerifiableEmail,
 } from "../../utils/generators";
 import { KJUR } from "jsrsasign";
-import { UserState } from "realm";
+import { Realm, UserState } from "realm";
 
 import { buildAppConfig } from "../../utils/build-app-config";
 
@@ -491,18 +491,18 @@ describe.skipIf(environment.missingServer, "User", () => {
           exports = async function (loginPayload) {
             // Get a handle for the app.users collection
             const users = context.services.get("mongodb").db("app").collection("users");
-          
+
             // Parse out custom data from the FunctionCredential
-          
+
             const { username, secret } = loginPayload;
-          
+
             if (secret !== "v3ry-s3cret") {
               throw new Error("Ah ah ah, you didn't say the magic word");
             }
             // Query for an existing user document with the specified username
-          
+
             const user = await users.findOne({ username });
-          
+
             if (user) {
               // If the user document exists, return its unique ID
               return user._id.toString();
@@ -574,4 +574,29 @@ describe.skipIf(environment.missingServer, "User", () => {
       await expect(user.functions.error()).to.be.rejectedWith("function not found: 'error'");
     });
   });
+  describe("currentUser", () => {
+    importAppBefore(buildAppConfig("with-anon-auth").anonAuth());
+
+    it("persists currentUser on opening the app", async function (this: AppContext & RealmContext) {
+      const credentials = Realm.Credentials.anonymous();
+      const user = await this.app.logIn(credentials);
+      const appId = this.app.id;
+      //@ts-expect-error Wanting to prove that a completely new app instance will still return the current logged in user
+      delete this.app;
+      this.app = new Realm.App(appId);
+
+      {
+        const currentUser = this.app.currentUser;
+        expect(currentUser).not.to.be.null;
+        expect(user.id).to.equal(currentUser?.id);
+      }
+
+      {
+        const newApp = new Realm.App(appId);
+        const currentUser = newApp.currentUser;
+        expect(currentUser).not.to.be.null;
+        expect(user.id).to.equal(currentUser?.id);
+      }
+    });
+  });
 });

packages/realm/src/app-services/App.ts

@@ -31,6 +31,9 @@ import {
   fs,
 } from "../internal";
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type AnyApp = App<any, any>;
+
 /**
  * This describes the options used to create a Realm App instance.
  */
@@ -86,9 +89,9 @@ type AppListenerToken = binding.AppSubscriptionToken;
  */
 export class App<FunctionsFactoryType = DefaultFunctionsFactory, CustomDataType = Record<string, unknown>> {
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  private static appById = new Map<string, binding.WeakRef<App<any, any>>>();
+  private static appById = new Map<string, binding.WeakRef<AnyApp>>();
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  private static appByUserId = new Map<string, binding.WeakRef<App<any, any>>>();
+  private static appByUserId = new Map<string, binding.WeakRef<AnyApp>>();
 
   /**
    * Get or create a singleton Realm App from an id.
@@ -110,12 +113,12 @@ export class App<FunctionsFactoryType = DefaultFunctionsFactory, CustomDataType
    * @returns The Realm App instance.
    */
   public static get(id: string): App {
-    const cachedApp = this.appById.get(id)?.deref();
+    const cachedApp = App.appById.get(id)?.deref();
     if (cachedApp) {
       return cachedApp;
     }
     const newApp = new App(id);
-    this.appById.set(id, new binding.WeakRef(newApp));
+    App.appById.set(id, new binding.WeakRef(newApp));
     return newApp;
   }
 
@@ -131,13 +134,20 @@ export class App<FunctionsFactoryType = DefaultFunctionsFactory, CustomDataType
 
   /** @internal */
   public static getAppByUser(userInternal: binding.SyncUser): App {
-    const app = this.appByUserId.get(userInternal.identity)?.deref();
+    const app = App.appByUserId.get(userInternal.identity)?.deref();
     if (!app) {
       throw new Error(`Cannot determine which app is associated with user (id = ${userInternal.identity})`);
     }
     return app;
   }
 
+  /** @internal */
+  public static setAppByUser(userInternal: binding.SyncUser, currentApp: AnyApp): void {
+    if (currentApp) {
+      App.appByUserId.set(userInternal.identity, new binding.WeakRef(currentApp));
+    }
+  }
+
   /** @internal */
   public internal: binding.App;
 
@@ -202,8 +212,7 @@ export class App<FunctionsFactoryType = DefaultFunctionsFactory, CustomDataType
 
   public async logIn(credentials: Credentials) {
     const userInternal = await this.internal.logInWithCredentials(credentials.internal);
-    App.appByUserId.set(userInternal.identity, new binding.WeakRef(this));
-    return new User(userInternal, this);
+    return User.get(userInternal, this);
   }
 
   public get emailPasswordAuth(): EmailPasswordAuth {
@@ -214,11 +223,11 @@ export class App<FunctionsFactoryType = DefaultFunctionsFactory, CustomDataType
 
   public get currentUser(): User<FunctionsFactoryType, CustomDataType> | null {
     const currentUser = this.internal.currentUser;
-    return currentUser ? User.get(currentUser) : null;
+    return currentUser ? User.get(currentUser, this) : null;
   }
 
   public get allUsers(): Readonly<Record<string, User<FunctionsFactoryType, CustomDataType>>> {
-    return Object.fromEntries(this.internal.allUsers.map((user) => [user.identity, User.get(user)]));
+    return Object.fromEntries(this.internal.allUsers.map((user) => [user.identity, User.get(user, this)]));
   }
 
   public switchUser(): unknown {

packages/realm/src/app-services/User.ts

@@ -17,6 +17,7 @@
 ////////////////////////////////////////////////////////////////////////////
 
 import {
+  AnyApp,
   ApiKeyAuth,
   App,
   Credentials,
@@ -104,7 +105,11 @@ export class User<
     FunctionsFactoryType = DefaultFunctionsFactory,
     CustomDataType = DefaultObject,
     UserProfileDataType = DefaultUserProfileData,
-  >(internal: binding.SyncUser) {
+  >(internal: binding.SyncUser, app?: AnyApp) {
+    // Update the static user reference to the current app
+    if (app) {
+      App.setAppByUser(internal, app);
+    }
     // TODO: Use a WeakRef to memoize the SDK object
     return new User<FunctionsFactoryType, CustomDataType, UserProfileDataType>(internal, App.getAppByUser(internal));
   }