feat: Implement gradual gas limit increase

[georgehao]

Fixes#315.

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing feat/gas_limit (224c40a) with scroll (079764e)}

Summary

✅ 77 untouched benchmarks

[georgehao]

https://github.com/scroll-tech/reth/actions/runs/20906978938/job/60062238660?pr=374

This is because Bincode is unmaintained https://github.com/paradigmxyz/reth/blob/main/deny.toml#L12

I think can ignore this lint error, wait for upstream merge

[frisitano]

Looks good! I think we should take this opportunity to do a bit of housekeeping on our block building types.

My proposal is as follows:
Update the ScrollBuilderConfig such that we remove the Option for gas_limit, such that it becomes:

pubstructScrollBuilderConfig{/// Gas limit.pubgas_limit:u64,/// Time limit for payload building.pubtime_limit:Duration,/// Maximum total data availability size for a block.pubmax_da_block_size:Option<u64>,}

This removes the need for the unwrap_or_default() which looks a bit scary here:

let desired_gas_limit = self.attributes().gas_limit.unwrap_or_else(|| builder_config.gas_limit.unwrap_or_default());

Update PayloadBuildingBreaker so the gas limit is no longer optional:

pubstructPayloadBuildingBreaker{start:Instant,time_limit:Duration,gas_limit:u64,max_da_block_size:Option<u64>,}

Introduce a method gas_limit on ScrollPayloadBuilderCtx:

/// Returns the gas limit for the new block.fngas_limit(&self,builder_gas_limit:u64) -> u64{let parent_gas_limit = self.parent().gas_limit();let target_gas_limit = self.attributes().gas_limit.unwrap_or(builder_gas_limit);calculate_block_gas_limit(parent_gas_limit, target_gas_limit)}

Update the method block_builder to be block_builder_with_breaker which returns both a block builder and a breaker:

/// Prepares a [`BlockBuilder`] for the next block.pubfnblock_builder_with_breaker<'a,DB:Database>(&'aself,db:&'amutState<DB>,builder_config:&ScrollBuilderConfig,) -> Result<(implBlockBuilder<Primitives = Evm::Primitives> + 'a,PayloadBuildingBreaker),PayloadBuilderError,>{// get the base fee for the attributes.let base_fee_provider = ScrollBaseFeeProvider::new(self.chain_spec.clone());let base_fee:u64 = base_fee_provider
.next_block_base_fee(db,self.parent().header(),self.attributes().timestamp()).map_err(|err| PayloadBuilderError::Other(Box::new(err)))?;let gas_limit = self.gas_limit(builder_config.gas_limit);let block_builder = self.evm_config.builder_for_next_block(
db,self.parent(),ScrollNextBlockEnvAttributes{timestamp:self.attributes().timestamp(),suggested_fee_recipient:self.attributes().suggested_fee_recipient(),
gas_limit,
base_fee,},).map_err(PayloadBuilderError::other)?;let breaker = PayloadBuildingBreaker::new(
builder_config.time_limit,
gas_limit,
builder_config.max_da_block_size,);Ok((block_builder, breaker))}

In ScrollBuilder::build(..) we do:

let(mut builder, breaker) = ctx.block_builder_with_breaker(&mut db, builder_config)?;

to get both the builder and the breaker. We should clean up any unused functions after these changes.

What do you think about this? cc: @Thegaram