Not able to set storage slot on hardhat network

Question

I am using the following code to set a slot to a value on hardhat network:

  public async setStorageAt(addr: EthAddress, slot: string, value: string): Promise<any> {
    const result = await this.provider.request({
      method: 'hardhat_setStorageAt',
      params: [addr.toString(), slot, value],
    });
    return result;
  }

And when I try to set the value of a slot

0x0c0c87e2d76a59631866640201b73cd5494944ef1f6c0605583699b7d52d4e8d,

I get the following error in the logs of hardhat network node:

hardhat_setStorageAt

  Errors encountered in param 1: Invalid value "0x0c0c87e2d76a59631866640201b73cd5494944ef1f6c0605583699b7d52d4e8d" supplied to : QUANTITY

Why am I receiving this error given that the value is smaller than the max storage slot index (2 ** 256)?

The contract I am interacting with is on mainnet and has the following address:

0xEd279fDD11cA84bEef15AF5D39BB4d4bEE23F0cA

Thank you

Answer 1

The issue was that the node doesn't expect there to be leading zeros. When I replaced this:

0x0c0c87e2d76a59631866640201b73cd5494944ef1f6c0605583699b7d52d4e8d

with:

0xc0c87e2d76a59631866640201b73cd5494944ef1f6c0605583699b7d52d4e8d

Everything worked.

I've used ethers.utils.hexStripZeros to achieve that:

const userBalanceSlot = utils.hexStripZeros(utils.keccak256(utils.defaultAbiCoder.encode(['address', 'uint'], [randomAddress, i])));