feat(testnet): add two new parameters --base-fee and --min-gas-price to the command evmosd testnet init-files

[luchenqun]

Description

Use the command evmosd testnet init-files --v 1 --output-dir ./nodes --chain-id evmos_9000-1 --keyring-backend test to generate the genesis.json file for the initial block. The feemarket params are as follows:

{
    "no_base_fee":false,
    "base_fee_change_denominator":8,
    "elasticity_multiplier":2,
    "enable_height":"0",
    "base_fee":"1000000000",
    "min_gas_price":"0.000000000000000000",
    "min_gas_multiplier":"0.500000000000000000"
}

In the genutil module, there is at least one genesis transaction for creating a validator, with the following content:

{
    "body":{
        "messages":[
            {
                "@type":"/cosmos.staking.v1beta1.MsgCreateValidator",
                "validator_address":"evmosvaloper1hajh...ur4y3khljfx82"
            }
        ]
    },
    "auth_info":{
        "fee":{
            "amount":[],
            "gas_limit":"0"
        }
    }
}

Based on the params in feemarket, The gasPrice for the transaction executed in block 0 must be max(base_fee, min_gas_price) = max(1000000000, 0.000000000000000000) = 1gwei

However, the MsgCreateValidator transaction does not meet the requirements of the feemarket params because the amount array in the fee is empty and the gas_limit is 0.

So why can this transaction be executed correctly? First, regarding the gasPrice check, when checking the transaction fee in NewDynamicFeeChecker, if the block height is 0, the check does not use the global fee, which is the feemarket related params. Instead, it uses the local fee, which is set in the app.toml as minimum-gas-prices. The default value for this parameter is 0aevmos. You can find the relevant code here: https://github.com/evmos/evmos/blob/v14.1.0/app/ante/evm/fee_checker.go#L27-L93

One possible issue that may arise from this is that when modifying the local fee, it may not be possible to start the chain using the genesis block. However, when I changed the local fee to minimum-gas-prices = "6aevmos" before start the chain using the genesis block, you can still use the genesis block to start the chain. In other words, although the checkTxFeeWithValidatorMinGasPrices function has been executed, it did not take effect.

After analyzing, this is because when executing transactions in the genutil module at block height 0, it directly skips the CheckTx stage and goes into DeliverTx. In the DeliverTx stage, ctx.minGasPrice is always an empty array. Only in the CheckTx stage is ctx.minGasPrice the one we set as 6aevmos. Therefore, checking the transaction fees with checkTxFeeWithValidatorMinGasPricesfor the transactions in the genutil module at block 0 has no meaning.

In #1760, I mentioned that we can treat transactions in genutil as special transactions. This way, I can modify the min_gas_price parameter in the genesis block's feemarket to be greater than 0, allowing the execution of transactions within the genutil module even when the transaction fee is 0. However, this suggestion was rejected. There was a suggestion to manually modify the transactions in the genutil module, but I find it inconvenient. I hope that the genesis.json file generated by evmosd testnet init-files can directly run without manual intervention.

I think the best solution would be to treat the transactions in the genutil module as regular transactions without any special handling, meaning that they must also comply with the feemarket params. When generating the genesis block using the evmosd testnet init-files command, the generated feemarket params would have a default min_gas_price of 0, which is not suitable for real scenarios. The solution is to specify the --base-fee and --min-gas-price parameters when executing the evmosd testnet init-files command to adjust the fees in the genutil module transactions based on the base fee and min gas price.

Ultimately, after implementing this feature, if you run the evmosd testnet init-files --v 1 --output-dir ./nodes --chain-id evmos_9000-1 --keyring-backend test --base-fee 10000000000 --min-gas-price 800000000 command, the generated feemarket parameters would be as follows:

{
    "no_base_fee":false,
    "base_fee_change_denominator":8,
    "elasticity_multiplier":2,
    "enable_height":"0",
    "base_fee":"10000000000",
    "min_gas_price":"800000000.000000000000000000",
    "min_gas_multiplier":"0.500000000000000000"
}

genutil generates the genesis block transaction based on the feemarket params. The content is roughly as follows:

{
    "body":{
        "messages":[
            {
                "@type":"/cosmos.staking.v1beta1.MsgCreateValidator",
                "validator_address":"evmosvaloper1hajh6rh....3khljfx82"
            }
        ]
    },
    "auth_info":{
        "fee":{
            "amount":[
                {
                    "denom":"aevmos",
                    "amount":"3000000000000000"
                }
            ],
            "gas_limit":"300000"
        }
    }
}

Note: fee = max(baseFee, minGasPrice)*gasLimit. The gasLimit is declared as a constant in the code as const CreateValidatorTxGasLimit = 300000.

Also, the evmosd testnet init-files command has an optional parameter called--minimum-gas-prices. This parameter is used to set the --minimum-gas-prices in the app.toml file, which affects the local fee. It should be noted that the -min-gas-price option mentioned in this commit modifies the global fee for feemarket params.

---

Closes #XXX

[fedekunze]

@luchenqun can you fix the conflicts?

[luchenqun]

@fedekunze The conflict has been resolved. I was using v14 code at the time, and it is now v15. In addition, I saw that lint did not pass, and it seems was not my relevant code.

[GAtom22]

Thanks for the contribution @luchenqun!!

Left a few comments

[GAtom22]

Actually, the default value for minimum_gas_prices flag is not zero

--minimum-gas-prices string    Minimum gas prices to accept for transactions; All fees in a tx must meet this minimum (e.g. 0.01photino,0.001stake) (default "0.000006aevmos")

However, for some reason, this is not stored properly in the app.toml file.

[luchenqun]

Actually, the default value for minimum_gas_prices flag is not zero

--minimum-gas-prices string    Minimum gas prices to accept for transactions; All fees in a tx must meet this minimum (e.g. 0.01photino,0.001stake) (default "0.000006aevmos")

However, for some reason, this is not stored properly in the app.toml file.

You are right, it does not take effect. You can directly modify the app.toml file manually after production configuration and change --minimum-gas-prices to the value you need.

[GAtom22]

Thanks for addressing the comments @luchenqun!!

Left a few more

[CLAassistant]

All committers have signed the CLA.

[GAtom22]

Please address the lint issue

[codecov]

Codecov Report

Merging #1864 (88da29b) into main (b826687) will increase coverage by 0.27%.
Report is 1 commits behind head on main.
The diff coverage is 100.00%.

❗ Current head 88da29b differs from pull request most recent head 81699c1. Consider uploading reports for the commit 81699c1 to get more accurate results

@@            Coverage Diff             @@
##             main    #1864      +/-   ##
==========================================
+ Coverage   69.70%   69.98%   +0.27%     
==========================================
  Files         331      327       -4     
  Lines       24514    24271     -243     
==========================================
- Hits        17088    16985     -103     
+ Misses       6543     6415     -128     
+ Partials      883      871      -12     

Files	Coverage Δ
app/ante/evm/fee_checker.go	100.00% <100.00%> (ø)

... and 8 files with indirect coverage changes

[luchenqun]

Actually, the default value for minimum_gas_prices flag is not zero

--minimum-gas-prices string    Minimum gas prices to accept for transactions; All fees in a tx must meet this minimum (e.g. 0.01photino,0.001stake) (default "0.000006aevmos")

However, for some reason, this is not stored properly in the app.toml file.

I have found the reason. It is because there is probably $HOME/.evmosd in your computer, and the minimum-gas-prices configured in app.toml has a higher priority than the fmt.Sprintf("0.000006%s" configured in the code. ", cmdcfg.BaseDenom)