This started with testing a simple Clarity contract that can stack its own STX through pool delegation.

The Short Story

Would there be an issue if the hexToBytes function were to check if the string starts with 0x, and remove it before processing the string?

Happy to submit a PR! 🚀

The Long Story

There were two function parameters that needed to be (buff 1) and (buff 20) to represent the pox address in delegate-stx.

The hex values were each stored in a constant:
(incorrect code below for illustration)

const poxVer = "0x01";
const poxHash = "0x13effebe0ea4bb45e35694f5a15bb5b96e851afb";

My first instinct was to use bufferCVFromString() on these two values, but the buffers were not the correct length as they were literally processing the string and returning (buff 3) and (buff 40). This made makeContractCall() fail with the tx options.

Next step was @friedger's suggestion to use bufferCV() and hexToBytes(), and after passing the string the contract call would be created but the broadcastTransaction() step would fail due to BadFunctionArguments.

After updating the constant to remove the leading 0x everything worked as expected, but it was quite the fight to get there and identify each problem.
(correct code below)

const poxVer = "01";
const poxHash = "13effebe0ea4bb45e35694f5a15bb5b96e851afb";

Relevant TX:
https://explorer.stacks.co/txid/0xdbbecf8113b530bd12ca67c425cc1c27a0bf7916ded65e106cf0ecc8fb28c75a?chain=mainnet