Extract PayloadTransactions to payload-primitives

[mattsse]

Describe the feature

we can move:

reth/crates/transaction-pool/src/traits.rs

Line 1518 in 7bd7c37

pub trait PayloadTransactions {

and implementers

reth/crates/transaction-pool/src/pool/best.rs

Line 446 in 7bd7c37

pub struct PayloadTransactionsChain<B: PayloadTransactions, A: PayloadTransactions> {

to this crate because this specifically targets payload building

reth/crates/payload/primitives/Cargo.toml

Line 2 in 7bd7c37

name = "reth-payload-primitives"

Additional context

No response

[TheDhejavu]

Took a quick look at the dependency relationship between reth-transaction-pool and reth-payload-primitives. Currently, reth-payload-primitives depends on reth-transaction-pool as shown

reth/crates/payload/primitives/Cargo.toml

Line 19 in 7bd7c37

reth-transaction-pool.workspace = true

If we want to move all payload-related implementers and traits to reth-payload-primitives, we'll encounter a dependency cycle issue. This is because:

1. We need to call reth-payload-primitives in reth-transaction-pool tests
2. Moving tests to reth-payload-primitives would require making reth-transaction-pool related methods that's used in test public

Currently, the only reason for reth-transaction-pool dependency in reth-payload-primitives is for error handling, as seen here

reth/crates/payload/primitives/src/error.rs

Line 6 in 7bd7c37

use reth_transaction_pool::BlobStoreError;

One approach is to remove the reth-transaction-pool dependency from reth-payload-primitives and only allow reth-transaction-pool to depend on reth-payload-primitives for payload-related functionality.

the downside is that we won't be able to move this

reth/crates/transaction-pool/src/pool/best.rs

Line 213 in 7bd7c37

pub struct BestPayloadTransactions<T, I>

because it depends reth-transaction-pool.

[mattsse]

I see, in that case, let's introduce a new crate for this like payload-util
this is probably better because eventually we need to put in a bunch of evm stuff in there anyway