Learning Discussions: How to correctly instantiate a new ContractB with ContractA.

[99Kies]

I want to implement a method in Contract A for instantiating a new contract.

And this is my first version code:

Is this the recommended way?

    let init_msg = AMaciInstantiateMsg {
        parameters: maci_parameters,
        coordinator: operator_pubkey,
        operator,
        admin: info.sender,
        max_vote_options: max_option,
        voice_credit_amount,
        round_info,
        voting_time,
        whitelist,
        pre_deactivate_root,
    };

    let msg = WasmMsg::Instantiate {
        admin: Some(env.contract.address.to_string()),
        code_id: amaci_code_id,
        msg: to_json_binary(&init_msg)?,
        funds: vec![],
        label: "AMACI".to_string(),
    };

    let resp = Response::new()
        .add_message(msg)
        .add_attribute("action", "create_maci_round");

    Ok(resp)
}

And I saw that there was the concept of reply and I didn't quite get what the need for reply was here?

    let init_msg = AMaciInstantiateMsg {
        parameters: maci_parameters,
        coordinator: operator_pubkey,
        operator,
        admin: info.sender,
        max_vote_options: max_option,
        voice_credit_amount,
        round_info,
        voting_time,
        whitelist,
        pre_deactivate_root,
    };

    let msg = WasmMsg::Instantiate {
        admin: Some(env.contract.address.to_string()),
        code_id: amaci_code_id,
        msg: to_json_binary(&init_msg)?,
        funds: vec![],
        label: "AMACI".to_string(),
    };

    // What are the roles of this one? What is typically handled in the reply method in the target contract(I mean the code_id contract, like `amaci_code_id` contract code)?
    let msg = SubMsg::reply_on_success(msg, INSTANTIATION_REPLY_ID);

    let resp = Response::new()
        .add_submessage(msg)
        .add_attribute("action", "create_maci_round");

    Ok(resp)
}

I mainly want to create the amaci_code_id contract with this method, which one do you guys recommend to use more? use the reply or not use is ok?

[chipshort]

Regarding your first example: Yes, this is the most simple way to instantiate a contract from within another contract.
If you just want to instantiate contract B and forget do nothing else, then this is the way.

As for the reply: I think you might be misunderstanding where this is called. The reply is not called on the newly instantiated contract (B), but on the contract that instantiates (A). It is often used to save the address of contract B into the state of contract A.
An alternative way to achieve this would be using Instantiate2.

[99Kies]

@chipshort can you give me an example with Instantiate2. I found out yesterday that the first method doesn't get the contract address, I do need to get the contract address and put the contract address in the event of Contract A.

Also, can I return the event output of contract B's instantiated contract to contract A?

[99Kies]

this is my contractA code: https://github.com/DoraFactory/cw-amaci/blob/main/contracts/registry/src/contract.rs#L211-L239
and this is my contractB code: https://github.com/DoraFactory/cw-amaci/blob/main/contracts/amaci/src/contract.rs#L2032-L2064

I'm currently hoping to be able to get the contract address by reply, and it would be best if I could inherit the event data. But I'm getting this error when calling contractA.
Error: rpc error: code = Unknown desc = rpc error: code = Unknown desc = failed to execute message; message index: 0: dispatch: submessages: reply: Error calling the VM: Error resolving Wasm function: Could not get export: Missing export reply: execute wasm contract failed [!cosm!wasm/[email protected]/x/wasm/keeper/keeper.go:555] With gas wanted: '350000000' and gas used: '13053926' : unknown request

https://github.com/DoraFactory/cw-amaci/blob/main/contracts/registry/src/multitest/tests.rs#L142-L184
And my test code return this error:
reply not implemented for contract

[99Kies]

I solved the problem with the test code with this code. https://github.com/DoraFactory/cw-amaci/blob/main/contracts/registry/src/multitest/mod.rs#L72

I observed that the event data does get inherited through the submessage form, and through the reply func, I also get the address of the contract.

So how to call this transaction correctly with cli or client?

[chipshort]

Here is an example for instantiate2:

cosmwasm/contracts/virus/src/contract.rs

Line 37 in 9e822c4

pub fn execute_spread(

Your test code is wired up incorrectly. As I explained before, the reply is called on contract A, but you are telling multitest to call contract B.

[99Kies]

Your test code is wired up incorrectly. As I explained before, the reply is called on contract A, but you are telling multitest to call contract B.

@chipshort Did you mean this? DoraFactory/cw-amaci@26e0554

[chipshort]

Yes, that's the line I meant. If you want to use the reply instead of instantiate2, you should implement the reply entrypoint in your registry contract and provide that to multitest there.

[99Kies]

@chipshort I'm clear on what it means, thanks for your patience! 🙏
DoraFactory/cw-amaci@161f4ad

It's worked now. haha

[99Kies]

@chipshort Is there any way to transfer the event in contractB to the reply method of contractA?
https://github.com/DoraFactory/cw-amaci/blob/main/contracts/registry/src/contract.rs#L382-L385

this is my event logs I need transfer to contractA(registry) reply func: https://github.com/DoraFactory/cw-amaci/blob/main/contracts/amaci/src/contract.rs#L276-L306

Because I'm running an indexer under the chain and need to log to the database based on this data. This is the transaction information sent by my current code, the event data is now too scattered adding to the difficulty of developing the indexer. If I can return all event data in reply, it will reduce my development difficulty. https://vota-testnet-explorer.dorafactory.org/doravotatestnet/tx/C45A865D9236A9478755AF09F6A259F7A396D20B4B0974E31EEEC2877AF3D731

[99Kies]

The way I use set_data seems to solve the problem, is this the recommended way to write it? Or is it safe?

https://github.com/DoraFactory/cw-amaci/blob/main/contracts/amaci/src/contract.rs#L276-L319
https://github.com/DoraFactory/cw-amaci/blob/main/contracts/registry/src/contract.rs#L383-L452