feat(wips): add wip for flashblock access lists

[0xOsiris]

Note

Low Risk
Documentation-only WIP addition with no runtime or consensus code changes in this PR.

Overview
Adds WIP-1007, a draft Networking standards track that defines Flashblock Access Lists (FAL) for sub-block flashblock pre-confirmations.

The WIP specifies an optional access_list_data field on ExecutionPayloadFlashblockDeltaV1: EIP-7928-style account/storage change records keyed by block access index, plus keccak256(rlp(access_list)), with canonical ordering and pruning rules. Builders may attach it; consumers with the field present can reconstruct per-tx pre-state, validate via parallel re-execution, and derive post-state roots from the diff, while absent payloads keep the legacy sequential path.

It also documents Amsterdam header reconstruction using EMPTY_BLOCK_ACCESS_LIST_HASH (sidecar not committed on-chain), builder recording rules, mandatory consumer verification steps, backwards compatibility, test expectations, and security notes (verify-before-trust, canonicalization, resource bounds).

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[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 3 potential issues.

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[cursor]

Later flashblock min index wrong

High Severity

The spec defines a later flashblock’s min_tx_index as prior committed transaction count plus one, but indices also cover pre-execution and per-flashblock system updates through max_tx_index. That formula can equal the previous flashblock’s highest used index instead of the next free index, overlapping ranges across flashblocks.

 

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[alessandromazza98]

do we want a wip for block access list? even if there is the official eip. I know that the current implementation slightly differs but we've not committed to this impl for prod, so we may end up directly using the official eip one as it's soon going to be merged for glamsterdam

[alessandromazza98]

approving to not block you, but I don't see a big utility for this wip

[0xOsiris]

approving to not block you, but I don't see a big utility for this wip

It's simply to document the implementation. Do you not think we should document it?

[alessandromazza98]

It's simply to document the implementation. Do you not think we should document it?

It's not a big deal, let's document and merge this

[0xOsiris]

do we want a wip for block access list? even if there is the official eip. I know that the current implementation slightly differs but we've not committed to this impl for prod, so we may end up directly using the official eip one as it's soon going to be merged for glamsterdam

The official EIP is an objectively worse implementation just in terms of performance. We can use a combination of both, where the block access list hash in the block header actually commits to the incremental access list of the stream.