[READ] Step 1: Are you in the right place?

• For issues related to the code in this repository file a Github issue.
• If the issue pertains to Cloud Firestore, read the instructions in the "Firestore issue"
  template.
• For general technical questions, post a question on StackOverflow
  with the firebase tag.
• For general Firebase discussion, use the firebase-talk
  google group.
• For help troubleshooting your application that does not fall under one
  of the above categories, reach out to the personalized
  Firebase support channel.

[REQUIRED] Step 2: Describe your environment

• Operating System version: windows 10
• Firebase SDK version: 12.1.1
• Firebase Product: admin
• Node.js version: 20.11.0
• NPM version: 10.2.4

[REQUIRED] Step 3: Describe the problem

When using the importUsers function, it is not correctly importing users where each one has a different hash key.

I am importing users where each user's password was created using HMAC sha1 but each user had its own key. I was trying to import 1 user per function call but when I import say 100 users one at a time, the majority of them import incorrectly(code below should make this easy to understand) . If I rerun a subset of around 10 users using the exact same information passed in they then will login correctly.

Is there some internal limitation or batching happening? I am importing users one at a time and respecting the API quotas and they are successful imports. This has been very confusing to understand the correct way to handle this scenario is and it feels difficult to understand a pattern.

Given they all import with no issues but only some actually log in correctly and when I rerun then more will work, tells me I am not passing in bad data but something about how they process is different each time.

Steps to reproduce:

What happened? How can we make the problem occur?
This could be a description, log/console output, etc.

Relevant Code:

The code below will generate 100 users and import them one at a time and then when I attempt to log in, only the last 10 ish will even work, all others get incorrect password errors.

const crypto = require('crypto');
const admin = require('firebase-admin');

var serviceAccount = require(".\\key.json");
admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
});

const randomString = (length) => {
    return Math.random().toString(36).slice(2, length + 2)
}

const users = [];
for(let i = 0; i <= 100; i++) {
    const text = 'password'
    const key = randomString(12);
    const passwordHash = crypto.createHmac('sha1', key)
    .update(text)
    .digest('hex')

    users.push({
        plainPassword: text,
        passwordHash,
        key,
        email_address: `${i}@gmail.com`,
        id: i.toString()
    })
}

async function start() {
    for (const user of users) {        
        const result = await admin.auth().importUsers([
            {
                uid: user.id,
                email: user.email_address,
                passwordHash: Buffer.from(user.passwordHash, 'hex'),
                emailVerified: true
            }
        ], {
            hash: {
                algorithm: "HMAC_SHA1",
                key: Buffer.from(user.key)
            }
        })

        console.log(result.errors[0]);
    }
}

start();