Can't restore derived wallets from BIP32 Root Key

[Dem0n13]

Ethers Version

6.0.8

Search Terms

fromExtendedKey, extendedKey, derivePath, path null

Describe the Problem

I'm playing with https://iancoleman.io/bip39/ utility and ethers library.
I'm trying to get what is BIP32 Root Key. As I understand I can use BIP32 Root Key to generate all derived keys instead of mnemonic phrase.
And I did it. But the main issue is null value in path property. Please look to the complete example below.

root.path which I got from mnemonic equals m as I expected.
But when I create restoredRoot using HDNodeWallet.fromExtendedKey method, restoredRoot.path equals null and there is no way to override it.
When I derive m/44'/60'/0'/0/0 and m/44'/60'/0'/0/1 from restoredRoot I get nulls in their paths too.

So the question: is there any way to restore wallets with right paths from extended private key?

Code Snippet

import { defaultPath, HDNodeWallet, Mnemonic } from "ethers";


async function main() {
    const phrase = "service any panther floor desert alcohol brown chair gold such wool swarm"
    const mnemonic = Mnemonic.fromPhrase(phrase)

    const hdNodeN = HDNodeWallet.fromMnemonic(mnemonic)
    console.log("wallet 0:", hdNodeN.path, hdNodeN.address, hdNodeN.privateKey) // m/44'/60'/0'/0/0 0x9e44A0F4F8EC569B8E9aE70acF267C18f143e697 0x253b0161fc932e9836b2b03593ff5521feca6c9e46bd6db43cb04715b7dbe9eb

    const hdNodeN1 = HDNodeWallet.fromMnemonic(mnemonic, "m/44'/60'/0'/0/1")
    console.log("wallet 1:", hdNodeN1.path, hdNodeN1.address, hdNodeN1.privateKey) // m/44'/60'/0'/0/1 0x1F0b5E19839E7D87CC0186F240bBDa2E8E3ED62A 0x0e8636c36508b5cf6d24186d8a43cb5a49cd43c2cfc1fdeac3335964bfe4ea98

    const root = HDNodeWallet.fromSeed(mnemonic.computeSeed())
    console.log("root:", root.path, root.address, root.privateKey) // m 0xa939792Fae4dd0CF141350ab1bcdEf89b0415423 0xffd7442d6a64b27535bfb053879d4599e6b48262be5db0df44c9dd529ccc705f

    const bip32RootKey = root.extendedKey
    console.log("BIP32 Root Key:", bip32RootKey) // xprv9s21ZrQH143K48uLpMjXMkv9acwYWXtgqujMZRr57CuQjCiQ7NT5TR7qLk3fYJ8WHjLVGK9uivoVWwU5RyXGavGw2H7X43vBUnPdHceHtnR

    const restoredRoot = HDNodeWallet.fromExtendedKey(bip32RootKey) as HDNodeWallet
    console.log("restored root:", restoredRoot.path, restoredRoot.address, restoredRoot.privateKey) // null 0xa939792Fae4dd0CF141350ab1bcdEf89b0415423 0xffd7442d6a64b27535bfb053879d4599e6b48262be5db0df44c9dd529ccc705f

    const restoredWallet0 = restoredRoot.derivePath(defaultPath)
    console.log("restored wallet 0:", restoredWallet0.path, restoredWallet0.address, restoredWallet0.privateKey) // null 0x9e44A0F4F8EC569B8E9aE70acF267C18f143e697 0x253b0161fc932e9836b2b03593ff5521feca6c9e46bd6db43cb04715b7dbe9eb

    const restoredWallet1 = restoredRoot.derivePath(defaultPath.slice(0, -1) + 1)
    console.log("restored wallet 1:", restoredWallet1.path, restoredWallet1.address, restoredWallet1.privateKey) // null 0x1F0b5E19839E7D87CC0186F240bBDa2E8E3ED62A 0x0e8636c36508b5cf6d24186d8a43cb5a49cd43c2cfc1fdeac3335964bfe4ea98
}


main();

Contract ABI

No response

Errors

No response

Environment

node.js (v12 or newer)

Environment (Other)

No response

[ricmoo]

Sorry for the long delay getting this question answered.

Unfortunately, the BIP-32 extended key does not encode the path in any way; it is designed to be of fixed length (which is a medium-to-hard requirement for encoding data using Base58), which doesn't allow for variable-length data to be encoded.

Sorry this likely doesn't help, but long story short is that the specification doesn't allow for it. :(