[rc8] examples/erc721 build upload/deployment fails with ContractTrapped

[agryaznov]

This error appears during uploading the contract through PolkadotJS Apps, however, it does not seem to be UI related, as it is clear that DispatchError is being returned from runtime:

Module: {
    index: 8
    error: 10
  }

(which is ContractTrapped from pallet_contracts)

The bug

examples/erc721 contract taken from ink! v3.0.0-rc8 builds successfully with cargo-contract 0.17

Uploading that build through PolkadotJS Apps v0.102.2 connected to substrate-contracts-node v0.5.0 fails with ContractTrapped

[xgreenx]

After the #1065, the constructor should be payable to be able to get a deposit for a contract.

@cmichi @athei Hmm, seems that the transferred balance will be always not zero during the instantiation of the contract. When constructor can be not payable? Maybe contract-pallet should subtract the deposit(minimum balance) from transferred value during instantiation?

[athei]

With the new automatic storage deposits we don't use the the transferred value in order to have the minimum balance. What will happen is that the required deposit is automatically transferred to the contracts account and is reserved there.

This is what allows us to have non payable constructors: The minimum deposit is handled by the pallet and the transferred value is only needed (or allowed) to be non zero if the contract logic requires it (payable constructor). Essentially constructors and messages behave exactly the same there now.

[athei]

Just tested with everything on master and apps v0.103.1. Deploy works for me. What did you enter as value?

[cmichi]

@agryaznov I also can't reproduce the error. I installed substrate-contracts-node with --locked.

[agryaznov]

The value was set to 1000 during deployment, which seems to be the reason of ContractTrapped as ERC721 constructor became non-payable by default (after storage deposits introduced with #10082 PR)...

With value = 0 the contract is being deployed successfully.

I think this will be an often mistake made by users who would likely specify non-zero endowment value on contract deployment, just on habit of a way how it used to work before.

[HCastano]

With value = 0 the contract is being deployed successfully.

I think this will be an often mistake made by users who would likely specify non-zero endowment value on contract deployment, just on habit of a way how it used to work before.

This won't be a problem in the future with polkadot-js/apps#6645. The UI won't show the value field if a constructor isn't marked explicitly as payable.

[athei]

Yeah so everything working as intended. The constructor isn't payable and therefore a ContractTrapped is exactly what we want here.

[xgreenx]

When I'm submitting the transaction about deployment with value zero it throw an contracts.NewContractNotFunded.
If I set the value 1 dot, it fails with contract trapped because the constructor is not payable. How do I need to instantiate the contract and pass 1 dot as endowment?

For testing I installed the node by the next command:

cargo install contracts-node --git https://github.com/paritytech/substrate-contracts-node.git --force --locked

[athei]

That can't be because this error doesn't exist anymore. So you are most likely testing against an older node than you think you are.

[xgreenx]

That can't be because this error doesn't exist anymore. So you are most likely testing against an older node than you think you are.

Yep, you are right, I had two nodes at the same time. With a new one everything works