two attempts to connect to auth emulator cause config error

[joaomelo]

[REQUIRED] Environment info

firebase-tools: 11.14.3
Platform: Windows 11

[REQUIRED] Test case

This repo commit.

[REQUIRED] Steps to reproduce

Clone the repo, install the project dependencies with npm i and firebase tools globally, open the windows terminal, and start emulators with firebase emulators:exec --project demo-test "vitest run"

[REQUIRED] Expected behavior

All test cases are able to connect to firebase emulators.

[REQUIRED] Actual behavior

After a test case connect to the emulators, the following ones will throw an error of config failed. See image:

But if we changed the connection code from this...

function connectToFirebase(connection) {
  const { useEmulators, ...config } = connection;

  const app = initializeApp(config);
  const auth = getAuth(app);
  const db = getFirestore(app);

  if (useEmulators) {
    connectAuthEmulator(auth, "http://localhost:9099", {
      disableWarnings: true,
    });
    connectFirestoreEmulator(db, "localhost", 8080);
  }

  const firebase = { app, auth, db };
  return firebase;
}

to this...

function connectToFirebase(connection) {
  const { useEmulators, ...config } = connection;

  const app = initializeApp(config);
  const auth = getAuth(app);
  const db = getFirestore(app);

  if (useEmulators && !auth.config.emulator) {
    connectAuthEmulator(auth, "http://localhost:9099", {
      disableWarnings: true,
    });
    connectFirestoreEmulator(db, "localhost", 8080);
  }

  const firebase = { app, auth, db };
  return firebase;
}

all connections go through all right.

I'm claiming this is a bug since there is no documented spec that claims a second connection attempt would fail and that the hack adopted here (!auth.config.emulator) uses an undocumented property that could change anytime. The consequence would be a fragile code that can be easily broken in a future path or minor release.

Thanks.
JM

[christhompsongoogle]

Thanks for the feedback - I'll forward to the team.

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[prameshj]

Thanks for filing this. Is it possible that network calls are being made before a second call to auth emulator? Any network call will result in the init flag set to false -

firebase-js-sdk/packages/auth/src/api/index.ts

Line 135 in 04dcdbb

(auth as AuthInternal)._canInitEmulator = false;

, so future connectAuthEmulator will fail.

we can update the docs to clarify this.

[joaomelo]

Hi @prameshj,
Thanks for answering.

I don't think a network call is made to the auth service before connecting to the auth emulator. The firebase setup is made at the beginning of the program lifecycle. This is the code:

function connectToFirebase(connection) {
  const { useEmulators, ...config } = connection;

  const app = initializeApp(config);
  const auth = getAuth(app);
  const db = getFirestore(app);

  if (useEmulators) {
    connectAuthEmulator(auth, "http://localhost:9099", {
      disableWarnings: true,
    });
    connectFirestoreEmulator(db, "localhost", 8080);
  }

  const firebase = { app, auth, db };
  return firebase;
}

But there is always the possibility of a bug in my code. Any suggestions on how I could ensure that and get back to you? Like two methods to spy on the execution order.

[prameshj]

Is "connectToFirebase" invoked before each test case? I wonder if this is because each test case makes some network calls (by calling some auth APIs) and hence the issue.

We could consider exposing "emulatorInitialized()" that returns a boolean, to be checked before invoking connectAuthEmulator. WDYT, @yuchenshi @sam-gc

[joaomelo]

Is "connectToFirebase" invoked before each test case? Yes, it is.

[bdotsamir]

Hi there! Thought I would chip in my two cents here,

I'm using react, and I made the rookie mistake of calling connectAuthEmulator() outside of a useEffect hook with an empty array of dependencies (thus acting like componentDidMount). Changing this made the error disappear.

Hope this helps!

(p.s: your repo link is broken)

[tzappia]

This one is still kicking around but I think it has become more of a problem now that SSR has become more prevalent. I raised a bug in the firebase-tools repo, but they investigated and suggested I raise the bug here.

If you look at the latest AngularFire sample app, even they include a hacky workaround for this issue by checking _canInitEmulator. Is there a reason this needs to be an error? The other emulators don't seem to care if you try to connect to them more than once. The call that is causing this is connectAuthEmulator, not initAuthEmulator, so if you need to init it the first time and not on subsequent calls to connect, I would hope you would just keep those details internal.

[DellaBitta]

Hi @joaomelo,

This should be fixed in our next release, with changes to Firestore, Auth and RTDB which allow the emulator connect functions to be called repeatedly, even after network operations have begun, so long as the parameters passed to the emulator connect functions is consistent.

Thanks for the bug report!