fix: #8759, default (low) gas limit set even when disabled, use custom gas_limit on forks

[nhtyy]

Motivation

#8759 and others I believe were mostly afflicted by the fact that most eth_call requests do not typically fill out the gas field on call requests (including alloy bindings), and if you weren't in forking mode, with disable_block_gas_limit, any incoming call without this field would be limited to 30M gas,

as you can see on line 1209 we try to get the requests gas field to setup the tx env, but its likely not there

foundry/crates/anvil/src/eth/backend/mem/mod.rs

Lines 1205 to 1231 in a592f7a

	max_priority_fee_per_gas,
	max_fee_per_blob_gas,
	} = fee_details;
	let gas_limit = gas.unwrap_or(block_env.gas_limit.to());
	let mut env = self.env.read().clone();
	env.block = block_env;
	// we want to disable this in eth_call, since this is common practice used by other node
	// impls and providers <https://github.com/foundry-rs/foundry/issues/4388>
	env.cfg.disable_block_gas_limit = true;
	// The basefee should be ignored for calls against state for
	// - eth_call
	// - eth_estimateGas
	// - eth_createAccessList
	// - tracing
	env.cfg.disable_base_fee = true;
	let gas_price = gas_price.or(max_fee_per_gas).unwrap_or_else(|| {
	self.fees().raw_gas_price().saturating_add(MIN_SUGGESTED_PRIORITY_FEE)
	});
	let caller = from.unwrap_or_default();
	let to = to.as_ref().and_then(TxKind::to);
	env.tx = TxEnv {
	caller,
	gas_limit: gas_limit as u64,
	gas_price: U256::from(gas_price),

so on line 1230 we set the tx.env.gas_limit to the block gas limit, however even when we set thedisable_block_gas_limit flag, this block gas limit defaults to 30_000_000 as seen here and here, which can make it seem like the flag is not working if the call youre testing is over 30M gas

Lastly, the fork mode appeared to work (as mentioned in #8759) because we branch if we have a fork, and in that branch we explicitly set the env block gas limit high if the flag is set , which would transitively apply to incoming calls.

foundry/crates/anvil/src/config.rs

Lines 1145 to 1160 in a592f7a

	// `0x0` which would inevitably result in `OutOfGas` errors as soon as the evm is about to record gas, See also <https://github.com/foundry-rs/foundry/issues/3247>
	let gas_limit = if self.disable_block_gas_limit || block.header.gas_limit == 0 {
	u64::MAX as u128
	} else {
	block.header.gas_limit
	};
	env.block = BlockEnv {
	number: U256::from(fork_block_number),
	timestamp: U256::from(block.header.timestamp),
	difficulty: block.header.difficulty,
	// ensures prevrandao is set
	prevrandao: Some(block.header.mix_hash.unwrap_or_default()),
	gas_limit: U256::from(gas_limit),
	// Keep previous `coinbase` and `basefee` value
	coinbase: env.block.coinbase,

Solution

In this PR there is breaking change (gas_limit is now an option on NodeConfig) to allow for using custom gas limits in forks, if we dont care about that then it doesnt need to breaking.

If the disable_block_gas_limit flag is set, make sure the block gas limit is high to ensure we dont limit incoming calls (without explicit gas_limit) to the default (low) limit

[nhtyy]

not sure about this

[mattsse]

this should be okay, but in case u128 the basefee would be more or less locked to the lowest possible value 7.
I assume this is okay if you disable the gas limit

[mattsse]

I think this makes sense.

could we two more test cases, one fork test for base and one where the gaslimit is disabled via config?

[mattsse]

this should be okay, but in case u128 the basefee would be more or less locked to the lowest possible value 7.
I assume this is okay if you disable the gas limit

[nhtyy]

@mattsse thanks, I added a test for base, and some potential tests for setting/disabling the gas limits on both forks and local

[mattsse]

last nits