How to get a detailed error for a Solang-compiled contract with polkadot-js?

Question

I'm currently using substrate (version 4) with the contrat-pallet. I deploy contract in wasm, compiled from solidity (thanks to solang compiler) and sometimes, when executing a method of the smart contract, I encounter an error. When I take a look on the polkadotjs apps I have the following message :

But this message is not so explicit and doesn't help to figure out how to solve the problem.

Furthermore, the output of the polkadotjs api when I run this code :

contract.tx.method({ storageDepositLimit, gasLimit })
.signAndSend(pair, result => {
    if (result.status.isFinalized) {
        return result.toHuman()
    }
})

is not really more explicit :

{
  dispatchError: { Module: { index: '9', error: '0x0b000000' } },
  dispatchInfo: { weight: '80,051,097,517', class: 'Normal', paysFee: 'Yes' },
  events: [
    { phase: [Object], event: [Object], topics: [] },
    { phase: [Object], event: [Object], topics: [] }
  ],
  internalError: undefined,
  status: {
    Finalized: '0x2e6cfa203369435efd17144525e265508e801865baf7d8f8989883a553ddf4b8'
  }
}

By experience, this kind of errors can occurs when a "require" from the solidity smart contract doesn't pass. But I don't have any details and I don't find how to get the require output message from the smart contract.

Is there any way to get more detail on error to know what is going on ? To get the message from the "require" in the solidity smart contract ? To know from what part it came from ?

Thanks !

Answer 1

Currently it is not yet possible to view the error message directly in the polkadot.js UI. To see your error message from the require statement you need to:

• Compile solang yourself from the latest master branch and use that. We added this feature recently and it is not yet released (it will be in V 0.2).
• Make sure your node is configured to display the debug buffer, as described here.