I found a few problems with this issue:

• I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.
• This issue does not seem to follow the issue template. Make sure you provide all the required information.

In addition, performing this in a transaction will eventually fail and terminate the function.
However, attaching the debugger it shows, the transaction is still attempted multiple times.
This seems incorrect.

exports.runMeTwice = onRequest(async (_, res) => {
    try {
        const firestore = defaultFirestore();
        await firestore.runTransaction(async (txn) => {
            txn.create(firestore.collection("test").doc("smt"), {});
        })
        logger.log("Created");
    } catch (error) {
        logger.log(error);
    } finally {
        res.end();
    }
});

Hi @jellynoone ,

I will take a look at this and get back to you.

@jellynoone

While investigating, there are some things can be tried as a workaround:

• Use set() instead
• DocumentReference.create() calls bulkWriter internally. You can try to use bulkWriter and config the retry option

This is the code I used to reproduce the issue against production, it throws Document already exists successfully.

const ref = randomCol.doc();
await ref.create({});
const snap1 = await ref.get();

await ref.create({});

Are you testing against production or emulator?

I'm testing this against the emulator. Did you try with the provided example?
I think the preferRest: true, configuration option might be significant.

Tested this again against the emulator, without preferRest the function completes with an error. With preferRest the function hangs.

@cherylEnkidu Did you perhaps have a chance to reevaluate based on the additional information provided?

Hi @jellynoone ,

I will continue the investigation this week, and I will reply the ticket as soon as I get any updates :)

Hi @cherylEnkidu were you able to take a look?

Hi @jellynoone ,

Thanks for the waiting. I tried the same code you provided, but the process never hangs. Could you please provided a small repo app?

Attaching a small repro app.

export.zip

Additional notes:

• The problem reproduces in:
  • emulated environments
  • against the live Firestore instance being called locally
• The function has to be called two times
  • The first call will complete normally
  • The second call will hang

@cherylEnkidu Attaching a video of the bug being reproduced.

In the video I'm using firebase emulators:start --project demo-me to start the emulators without needing a real project. However, I tested this with a live Firestore instance and emulated functions and observed the same bug.

In addition, in the video I'm calling curl instead of the browser to make the process more streamlined.