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fix(evmstate/test): stabilize trace tx tests with deterministic ERC20 transfer recipient #2418

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Unique-Divine merged 2 commits into from
Oct 28, 2025
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fix(evmstate/test): stabilize trace tx tests with deterministic ERC20 transfer recipient #2418

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fix(evmstate/test): fix flaky trace tx tests with deterministic ERC20…
Unique-Divine Oct 28, 2025
4ae0d1a
changelog
Unique-Divine Oct 28, 2025
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4 changes: 3 additions & 1 deletion CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,9 @@ changelog format](https://keepachangelog.com/en/1.0.0/).
See https://github.com/dangoslen/changelog-enforcer.
-->

## [v2.8.0](https://github.com/NibiruChain/nibiru/releases/tag/v2.8.0) - 2025-10-24
- [#2418](https://github.com/NibiruChain/nibiru/pull/2418) - fix(evmstate/test): stabilize trace tx tests with deterministic ERC20 transfer recipient

## [v2.8.0](https://github.com/NibiruChain/nibiru/releases/tag/v2.8.0) - 2025-10-28

- [#2385](https://github.com/NibiruChain/nibiru/pull/2385) - evm: 63/64 gas clamp for ERC20 calls; improved VM error surfacing; add composite Chainlink-like oracle
- [#2388](https://github.com/NibiruChain/nibiru/pull/2388) - chore: erc20 token registry new tokens: cbBTC, uBTC
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4 changes: 2 additions & 2 deletions x/evm/evmstate/grpc_query_test.go
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Expand Up @@ -52,8 +52,8 @@ func TraceNibiTransfer() string {
func TraceResCallTracer_ERC20Transfer(
fromAddr, toAddr gethcommon.Address,
) (traceResFields map[string]string) {
gas := hexutil.Uint64(51_250)
gasUsed := hexutil.Uint64(34_150)
gas := hexutil.Uint64(51_046) // "0xc766"
gasUsed := hexutil.Uint64(33_946) // "0x849a"

f := make(map[string]string)
f["from"] = fromAddr.Hex()
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43 changes: 38 additions & 5 deletions x/evm/evmtest/tx.go
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Expand Up @@ -99,14 +99,47 @@ func DeployContract(
}, nil
}

// DeployAndExecuteERC20Transfer deploys contract, executes transfer and returns tx hash
// DeployAndExecuteERC20Transfer deploys a test ERC-20, executes one transfer,
// and returns the transfer tx, the deploy tx (as a predecessor), and the
// contract address.
//
// ## Determinism: Why we use a fixed recipient address
//
// Intrinsic gas charges depend on calldata bytes. Since Istanbul (EIP-2028),
// each zero byte is 4 gas and each non-zero byte is 16 gas (+12 per non-zero
// byte). In an ERC-20 transfer(address,uint256), the address occupies the last
// 20 bytes of a 32-byte word (left-padded with zeros). Random recipients change
// the count of non-zero bytes and make gas/gasUsed assertions flaky.
//
// To keep tests stable, this helper uses a fixed recipient address whose byte
// pattern is constant. The intrinsic gas term is then reproducible.
//
// References:
// - EIP-2028: https://eips.ethereum.org/EIPS/eip-2028
// - Solidity ABI padding rules: https://docs.soliditylang.org/en/latest/abi-spec.html
func DeployAndExecuteERC20Transfer(
deps *TestDeps, t *testing.T,
) (
erc20Transfer *evm.MsgEthereumTx,
predecessors []*evm.MsgEthereumTx,
contractAddr gethcommon.Address,
erc20Transfer *evm.MsgEthereumTx, // the signed transfer tx
predecessors []*evm.MsgEthereumTx, // slice containing the deploy tx
contractAddr gethcommon.Address, // ERC20 token being transferred
) {
var (
// Use a deterministic recipient to avoid nondeterministic intrinsic gas from calldata
// (non-zero vs zero byte costs). A fixed address ensures stable gas/gasUsed in traces.
//
// This address, "0x0000000000000000000000000000000000010f2C", has only 3
// non-zero bytes in its 20-byte payload (01, 0f, 2c). This means we expect
// it to have lower intrinsic gas than a "typical" random address that has
// ~20 non-zero bytes. Lower by (20 - 3) * 12 = 204 gas units, based on
// EIP-2028 (Istanbul upgrade).
//
// Istanbul reduced the calldata charge to 4 gas
// per zero byte and 16 per non-zero byte, which is why changing the address
// bytes moves intrinsic gas in steps of 12.
fixedRecipient = gethcommon.BigToAddress(big.NewInt(69_420))
)
Comment on lines +127 to +141
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@gemini-code-assist gemini-code-assist bot Oct 28, 2025

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medium

To improve readability and maintainability, consider defining 69_420 as a named constant. This avoids using a magic number directly in the function body. The var block for a single variable is also slightly unconventional. This suggestion refactors the block to use a const.

Suggested change
var (
// Use a deterministic recipient to avoid nondeterministic intrinsic gas from calldata
// (non-zero vs zero byte costs). A fixed address ensures stable gas/gasUsed in traces.
//
// This address, "0x0000000000000000000000000000000000010f2C", has only 3
// non-zero bytes in its 20-byte payload (01, 0f, 2c). This means we expect
// it to have lower intrinsic gas than a "typical" random address that has
// ~20 non-zero bytes. Lower by (20 - 3) * 12 = 204 gas units, based on
// EIP-2028 (Istanbul upgrade).
//
// Istanbul reduced the calldata charge to 4 gas
// per zero byte and 16 per non-zero byte, which is why changing the address
// bytes moves intrinsic gas in steps of 12.
fixedRecipient = gethcommon.BigToAddress(big.NewInt(69_420))
)
const fixedRecipientInt = 69_420
// Use a deterministic recipient to avoid nondeterministic intrinsic gas from calldata
// (non-zero vs zero byte costs). A fixed address ensures stable gas/gasUsed in traces.
//
// This address, "0x0000000000000000000000000000000000010f2C", has only 3
// non-zero bytes in its 20-byte payload (01, 0f, 2c). This means we expect
// it to have lower intrinsic gas than a "typical" random address that has
// ~20 non-zero bytes. Lower by (20 - 3) * 12 = 204 gas units, based on
// EIP-2028 (Istanbul upgrade).
//
// Istanbul reduced the calldata charge to 4 gas
// per zero byte and 16 per non-zero byte, which is why changing the address
// bytes moves intrinsic gas in steps of 12.
fixedRecipient := gethcommon.BigToAddress(big.NewInt(fixedRecipientInt))


// TX 1: Deploy ERC-20 contract
deployResp, err := DeployContract(deps, embeds.SmartContract_TestERC20)
require.NoError(t, err)
Expand All @@ -122,7 +155,7 @@ func DeployAndExecuteERC20Transfer(

// TX 2: execute ERC-20 contract transfer
input, err := contractData.ABI.Pack(
"transfer", NewEthPrivAcc().EthAddr, new(big.Int).SetUint64(1000),
"transfer", fixedRecipient, new(big.Int).SetUint64(1000),
)
require.NoError(t, err)
nonce = deps.NewStateDB().GetNonce(deps.Sender.EthAddr)
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