fix(AppCheck): Fixed getToken promise not being cleared

packages/app-check/src/internal-api.test.ts

@@ -368,6 +368,103 @@ describe('internal api', () => {
       });
     });
 
+    it('no dangling exchangeToken promise internal', async () => {
+      const appCheck = initializeAppCheck(app, {
+        provider: new ReCaptchaV3Provider(FAKE_SITE_KEY)
+      });
+
+      setState(app, {
+        ...getState(app),
+        token: fakeRecaptchaAppCheckToken,
+        cachedTokenPromise: undefined
+      });
+
+      stub(reCAPTCHA, 'getToken').returns(Promise.resolve(fakeRecaptchaToken));
+      stub(client, 'exchangeToken').returns(
+        Promise.resolve({
+          token: 'new-recaptcha-app-check-token',
+          expireTimeMillis: Date.now() + 60000,
+          issuedAtTimeMillis: 0
+        })
+      );
+
+      const getTokenPromise = getToken(appCheck as AppCheckService, true);
+
+      expect(getState(app).exchangeTokenFetcher.promise).to.be.instanceOf(
+        Promise
+      );
+
+      const state = {
+        ...getState(app)
+      };
+
+      await getTokenPromise;
+
+      setState(app, state);
+
+      expect(getState(app).exchangeTokenFetcher.promise).to.be.equal(undefined);
+    });
+
+    it('no dangling exchangeToken promise', async () => {
+      const clock = useFakeTimers();
+
+      const appCheck = initializeAppCheck(app, {
+        provider: new ReCaptchaV3Provider(FAKE_SITE_KEY)
+      });
+
+      const soonExpiredToken = {
+        token: `recaptcha-app-check-token-old`,
+        expireTimeMillis: Date.now() + 1000,
+        issuedAtTimeMillis: 0
+      };
+
+      setState(app, {
+        ...getState(app),
+        token: soonExpiredToken,
+        cachedTokenPromise: undefined
+      });
+
+      stub(reCAPTCHA, 'getToken').returns(Promise.resolve(fakeRecaptchaToken));
+      let count = 0;
+      stub(client, 'exchangeToken').callsFake(
+        () =>
+          new Promise(res =>
+            setTimeout(
+              () =>
+                res({
+                  token: `recaptcha-app-check-token-new-${count++}`,
+                  expireTimeMillis: Date.now() + 60000,
+                  issuedAtTimeMillis: 0
+                }),
+              3000
+            )
+          )
+      );
+
+      // start fetch token
+      void getToken(appCheck as AppCheckService, true);
+
+      clock.tick(2000);
+
+      // save expired `token-old` with copied state and wait fetch token
+      void getToken(appCheck as AppCheckService);
+
+      // wait fetch token with copied state
+      void getToken(appCheck as AppCheckService);
+
+      // stored copied state with `token-new-0`
+      await clock.runAllAsync();
+
+      // fetch token with copied state
+      const newToken = getToken(appCheck as AppCheckService, true);
+
+      await clock.runAllAsync();
+
+      expect(await newToken).to.deep.equal({
+        token: 'recaptcha-app-check-token-new-1'
+      });
+    });
+
     it('ignores in-memory token if it is invalid and continues to exchange request', async () => {
       const appCheck = initializeAppCheck(app, {
         provider: new ReCaptchaV3Provider(FAKE_SITE_KEY)

packages/app-check/src/internal-api.ts

@@ -117,18 +117,18 @@ export async function getToken(
    */
   if (isDebugMode()) {
     // Avoid making another call to the exchange endpoint if one is in flight.
-    if (!state.exchangeTokenPromise) {
-      state.exchangeTokenPromise = exchangeToken(
+    if (!state.exchangeTokenFetcher.promise) {
+      state.exchangeTokenFetcher.promise = exchangeToken(
         getExchangeDebugTokenRequest(app, await getDebugToken()),
         appCheck.heartbeatServiceProvider
       ).finally(() => {
         // Clear promise when settled - either resolved or rejected.
-        state.exchangeTokenPromise = undefined;
+        state.exchangeTokenFetcher.promise = undefined;
       });
       shouldCallListeners = true;
     }
-    const tokenFromDebugExchange: AppCheckTokenInternal =
-      await state.exchangeTokenPromise;
+    const tokenFromDebugExchange: AppCheckTokenInternal = await state
+      .exchangeTokenFetcher.promise;
     // Write debug token to indexedDB.
     await writeTokenToStorage(app, tokenFromDebugExchange);
     // Write debug token to state.
@@ -143,17 +143,19 @@ export async function getToken(
    */
   try {
     // Avoid making another call to the exchange endpoint if one is in flight.
-    if (!state.exchangeTokenPromise) {
+    if (!state.exchangeTokenFetcher.promise) {
       // state.provider is populated in initializeAppCheck()
       // ensureActivated() at the top of this function checks that
       // initializeAppCheck() has been called.
-      state.exchangeTokenPromise = state.provider!.getToken().finally(() => {
-        // Clear promise when settled - either resolved or rejected.
-        state.exchangeTokenPromise = undefined;
-      });
+      state.exchangeTokenFetcher.promise = state
+        .provider!.getToken()
+        .finally(() => {
+          // Clear promise when settled - either resolved or rejected.
+          state.exchangeTokenFetcher.promise = undefined;
+        });
       shouldCallListeners = true;
     }
-    token = await state.exchangeTokenPromise;
+    token = await state.exchangeTokenFetcher.promise;
   } catch (e) {
     if ((e as FirebaseError).code === `appCheck/${AppCheckError.THROTTLED}`) {
       // Warn if throttled, but do not treat it as an error.

packages/app-check/src/state.ts

@@ -30,7 +30,9 @@ export interface AppCheckState {
   provider?: AppCheckProvider;
   token?: AppCheckTokenInternal;
   cachedTokenPromise?: Promise<AppCheckTokenInternal | undefined>;
-  exchangeTokenPromise?: Promise<AppCheckTokenInternal>;
+  exchangeTokenFetcher: {
+    promise?: Promise<AppCheckTokenInternal>;
+  };
   tokenRefresher?: Refresher;
   reCAPTCHAState?: ReCAPTCHAState;
   isTokenAutoRefreshEnabled?: boolean;
@@ -50,7 +52,8 @@ export interface DebugState {
 const APP_CHECK_STATES = new Map<FirebaseApp, AppCheckState>();
 export const DEFAULT_STATE: AppCheckState = {
   activated: false,
-  tokenObservers: []
+  tokenObservers: [],
+  exchangeTokenFetcher: {}
 };
 
 const DEBUG_STATE: DebugState = {