CallResult will sometimes return different gas used and refunded whether createTransaction is true or false

[0xpolarzero]

Description

With some calls, depending on whether Tevm.contract:createTransaction is set to true or false, the returned CallResult.executionGasUsed and CallResult.gasRefund will be different.

Take this example using two instances of the same token:

// Mint some of each tokens and approve the airdrop contract for spending them
await mintAndApproveBoth(tevm);
// Airdrop tokens
const gasData = await airdropBoth(tevm);

...

// ? LOGS:
// ┌─────────┬─────────┬───────────┐
// │ (index) │ gasUsed │ gasRefund │
// ├─────────┼─────────┼───────────┤
// │  false  │  63218  │   29500   │
// │  true   │  51118  │   59700   │
// │  diff   │ -12100  │   30200   │
// └─────────┴─────────┴───────────┘
// ? 'airdropERC20' with createTransaction: true used 12,100 less gas
// ? and refunded 30,200 more gas than with createTransaction: false

In this example, while there is no difference in gas for regular mint and approve ERC20 interactions, calling airdropERC20 on a custom airdrop contract will not return the same gas data whether the transaction is executed in a sandbox environment or in the same context as the previous ones.

Regardless of the parameters (lengths and values of the recipients/amounts), this will always return the same 12,100 decrease in gas used and 30,200 increase in gas refunded with createTransaction: true.

As a side note, compared to a testnet transaction, the amount of gas used during execution seems more realistic with createTransaction: false.

Version

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[roninjin10]

There has been a lot of churn in Tevm. This might have been accidentally fixed but hasn't been verified yet