Update BlindedBlobsBundle SSZ list max length and update builder tests (#4710)

* Update mev-rs and ethereum-consensus * Fix mock buidler open bid to return fork versioned response * Update `mev-rs` and `ethereum-consensus` * Remove BuilderKzgCommitments and use BlockBodyKzgCommitments everywhere. * Update testnet scripts to support builder testing and update README.md. * Add comment on `mev-rs` version. * Add `BN_ARGS` config to `./scripts/tests/vars.env` * Update builder testing command in README.md * Reject zero block hash payloads after Bellatrix. * Update scripts/local_testnet/README.md Co-authored-by: realbigsean <seananderson33@GMAIL.com> --------- Co-authored-by: realbigsean <seananderson33@GMAIL.com>
2023-09-09 16:10:15 +10:00 · 2023-09-09 16:10:15 +10:00 · 1db739490e
commit 1db739490e
parent 50bf40b4bc
21 changed files with 87 additions and 78 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -528,7 +528,7 @@ checksum = "8c3c1a368f70d6cf7302d78f8f7093da241fb8e8807c05cc9e51a125895a6d5b"
 [[package]]
 name = "beacon-api-client"
 version = "0.1.0"
-source = "git+https://github.com/ralexstokes/beacon-api-client?rev=56a290c#56a290ca9d2c67086917a0929cdf2fe35e5f917f"
+source = "git+https://github.com/ralexstokes/beacon-api-client?rev=7f28993615fde52d563dd601a0511c34fe9b7c38#7f28993615fde52d563dd601a0511c34fe9b7c38"
 dependencies = [
 "clap 4.3.21",
 "ethereum-consensus",
@ -2413,7 +2413,7 @@ dependencies = [
 [[package]]
 name = "ethereum-consensus"
 version = "0.1.1"
-source = "git+https://github.com/jimmygchen/ethereum-consensus?rev=2354493#2354493fd631b736c189868b7dc1b415a160f0f7"
+source = "git+https://github.com/ralexstokes/ethereum-consensus?rev=12508c1f9b0c8f4bf4c5e9b6d441e840c1b37fd9#12508c1f9b0c8f4bf4c5e9b6d441e840c1b37fd9"
 dependencies = [
 "async-stream",
 "blst",
@ -4906,7 +4906,7 @@ dependencies = [
 [[package]]
 name = "mev-rs"
 version = "0.3.0"
-source = "git+https://github.com/ralexstokes/mev-rs?rev=9d88a2386b58c2948fa850f0dd4b3dfe18bd4962#9d88a2386b58c2948fa850f0dd4b3dfe18bd4962"
+source = "git+https://github.com/jimmygchen/mev-rs?rev=dedc77a#dedc77a796986603fb3376c5f353863d09e0dbf2"
 dependencies = [
 "anvil-rpc",
 "async-trait",
--- a/Cargo.toml
+++ b/Cargo.toml
@ -94,10 +94,6 @@ resolver = "2"
 [patch.crates-io]
 warp = { git = "https://github.com/macladson/warp", rev="7e75acc368229a46a236a8c991bf251fe7fe50ef" }

-# PR: https://github.com/ralexstokes/ethereum-consensus/pull/213
-[patch."https://github.com/ralexstokes/ethereum-consensus"]
-ethereum-consensus = { git = "https://github.com/jimmygchen/ethereum-consensus", rev = "2354493" }
-
 [profile.maxperf]
 inherits = "release"
 lto = "fat"
--- a/beacon_node/beacon_chain/src/beacon_chain.rs
+++ b/beacon_node/beacon_chain/src/beacon_chain.rs
@ -118,7 +118,6 @@ use store::{
 use task_executor::{ShutdownReason, TaskExecutor};
 use tokio_stream::Stream;
 use tree_hash::TreeHash;
-use types::beacon_block_body::from_block_kzg_commitments;
 use types::beacon_state::CloneConfig;
 use types::blob_sidecar::{BlobSidecarList, FixedBlobSidecarList};
 use types::sidecar::BlobItems;
@ -4994,11 +4993,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
            metrics::start_timer(&metrics::BLOCK_PRODUCTION_BLOBS_VERIFICATION_TIMES);
        let maybe_sidecar_list = match (blobs_opt, proofs_opt) {
            (Some(blobs_or_blobs_roots), Some(proofs)) => {
-                let expected_kzg_commitments = block
-                    .body()
-                    .blob_kzg_commitments()
-                    .map(from_block_kzg_commitments::<T::EthSpec>)
-                    .map_err(|_| {
+                let expected_kzg_commitments =
+                    block.body().blob_kzg_commitments().map_err(|_| {
                        BlockProductionError::InvalidBlockVariant(
                            "deneb block does not contain kzg commitments".to_string(),
                        )
@ -5022,7 +5018,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                        .ok_or(BlockProductionError::TrustedSetupNotInitialized)?;
                    kzg_utils::validate_blobs::<T::EthSpec>(
                        kzg,
-                        &expected_kzg_commitments,
+                        expected_kzg_commitments,
                        blobs,
                        &kzg_proofs,
                    )
@ -5033,7 +5029,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                    Sidecar::build_sidecar(
                        blobs_or_blobs_roots,
                        &block,
-                        &expected_kzg_commitments,
+                        expected_kzg_commitments,
                        kzg_proofs,
                    )
                    .map_err(BlockProductionError::FailedToBuildBlobSidecars)?,
--- a/beacon_node/execution_layer/Cargo.toml
+++ b/beacon_node/execution_layer/Cargo.toml
@ -42,8 +42,9 @@ lazy_static = "1.4.0"
 ethers-core = "1.0.2"
 builder_client = { path = "../builder_client" }
 fork_choice = { path = "../../consensus/fork_choice" }
-mev-rs = { git = "https://github.com/ralexstokes/mev-rs", rev = "9d88a2386b58c2948fa850f0dd4b3dfe18bd4962" }
-ethereum-consensus = { git = "https://github.com/ralexstokes/ethereum-consensus", rev = "56418ea" }
+#PR: https://github.com/ralexstokes/mev-rs/pull/124
+mev-rs = { git = "https://github.com/jimmygchen/mev-rs", rev = "dedc77a" }
+ethereum-consensus = { git = "https://github.com/ralexstokes/ethereum-consensus", rev = "12508c1f9b0c8f4bf4c5e9b6d441e840c1b37fd9" }
 ssz_rs = "0.9.0"
 tokio-stream = { version = "0.1.9", features = [ "sync" ] }
 strum = "0.24.0"
--- a/beacon_node/execution_layer/src/engine_api/json_structures.rs
+++ b/beacon_node/execution_layer/src/engine_api/json_structures.rs
@ -2,7 +2,7 @@ use super::*;
 use serde::{Deserialize, Serialize};
 use strum::EnumString;
 use superstruct::superstruct;
-use types::beacon_block_body::BuilderKzgCommitments;
+use types::beacon_block_body::KzgCommitments;
 use types::blob_sidecar::BlobsList;
 use types::{
    EthSpec, ExecutionBlockHash, ExecutionPayload, ExecutionPayloadCapella, ExecutionPayloadDeneb,
@ -438,7 +438,7 @@ impl From<JsonPayloadAttributes> for PayloadAttributes {
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 #[serde(bound = "E: EthSpec", rename_all = "camelCase")]
 pub struct JsonBlobsBundleV1<E: EthSpec> {
-    pub commitments: BuilderKzgCommitments<E>,
+    pub commitments: KzgCommitments<E>,
    pub proofs: KzgProofs<E>,
    #[serde(with = "ssz_types::serde_utils::list_of_hex_fixed_vec")]
    pub blobs: BlobsList<E>,
--- a/beacon_node/execution_layer/src/lib.rs
+++ b/beacon_node/execution_layer/src/lib.rs
@ -39,7 +39,7 @@ use tokio::{
 };
 use tokio_stream::wrappers::WatchStream;
 use tree_hash::TreeHash;
-use types::beacon_block_body::{to_block_kzg_commitments, BlockBodyKzgCommitments};
+use types::beacon_block_body::KzgCommitments;
 use types::builder_bid::BuilderBid;
 use types::sidecar::{BlobItems, Sidecar};
 use types::KzgProofs;
@ -110,9 +110,7 @@ impl<E: EthSpec, Payload: AbstractExecPayload<E>> TryFrom<BuilderBid<E>>
                    .try_into()
                    .map_err(|_| Error::InvalidPayloadConversion)?,
                block_value: builder_bid.value,
-                kzg_commitments: to_block_kzg_commitments::<E>(
-                    builder_bid.blinded_blobs_bundle.commitments,
-                ),
+                kzg_commitments: builder_bid.blinded_blobs_bundle.commitments,
                blobs: BlobItems::try_from_blob_roots(builder_bid.blinded_blobs_bundle.blob_roots)
                    .map_err(Error::InvalidBlobConversion)?,
                proofs: builder_bid.blinded_blobs_bundle.proofs,
@ -168,7 +166,7 @@ pub enum BlockProposalContents<T: EthSpec, Payload: AbstractExecPayload<T>> {
    PayloadAndBlobs {
        payload: Payload,
        block_value: Uint256,
-        kzg_commitments: BlockBodyKzgCommitments<T>,
+        kzg_commitments: KzgCommitments<T>,
        blobs: <Payload::Sidecar as Sidecar<T>>::BlobItems,
        proofs: KzgProofs<T>,
    },
@ -185,7 +183,7 @@ impl<E: EthSpec, Payload: AbstractExecPayload<E>> TryFrom<GetPayloadResponse<E>>
            Some(bundle) => Ok(Self::PayloadAndBlobs {
                payload: execution_payload.into(),
                block_value,
-                kzg_commitments: to_block_kzg_commitments::<E>(bundle.commitments),
+                kzg_commitments: bundle.commitments,
                blobs: BlobItems::try_from_blobs(bundle.blobs)
                    .map_err(Error::InvalidBlobConversion)?,
                proofs: bundle.proofs,
@ -204,7 +202,7 @@ impl<T: EthSpec, Payload: AbstractExecPayload<T>> BlockProposalContents<T, Paylo
        self,
    ) -> (
        Payload,
-        Option<BlockBodyKzgCommitments<T>>,
+        Option<KzgCommitments<T>>,
        Option<<Payload::Sidecar as Sidecar<T>>::BlobItems>,
        Option<KzgProofs<T>>,
    ) {
--- a/beacon_node/execution_layer/src/test_utils/mock_builder.rs
+++ b/beacon_node/execution_layer/src/test_utils/mock_builder.rs
@ -39,7 +39,7 @@ use tree_hash::TreeHash;
 use types::builder_bid::BlindedBlobsBundle;
 use types::{
    Address, BeaconState, ChainSpec, EthSpec, ExecPayload, ExecutionPayload,
-    ExecutionPayloadHeader, ForkName, Hash256, Slot, Uint256,
+    ExecutionPayloadHeader, ForkName, ForkVersionedResponse, Hash256, Slot, Uint256,
 };

 #[derive(Clone)]
@ -533,7 +533,13 @@ impl<E: EthSpec> mev_rs::BlindedBlockProvider for MockBuilder<E> {
            .get_payload_by_root(&from_ssz_rs(&node)?)
            .ok_or_else(|| convert_err("missing payload for tx root"))?;

-        let json_payload = serde_json::to_string(&payload).map_err(convert_err)?;
+        let fork = payload.payload_ref().fork_name();
+        let resp = ForkVersionedResponse {
+            version: Some(fork),
+            data: payload,
+        };
+
+        let json_payload = serde_json::to_string(&resp).map_err(convert_err)?;
        serde_json::from_str(json_payload.as_str()).map_err(convert_err)
    }
 }
--- a/beacon_node/http_api/src/publish_blocks.rs
+++ b/beacon_node/http_api/src/publish_blocks.rs
@ -20,7 +20,7 @@ use tokio::sync::mpsc::UnboundedSender;
 use tree_hash::TreeHash;
 use types::{
    AbstractExecPayload, BeaconBlockRef, BlindedPayload, EthSpec, ExecPayload, ExecutionBlockHash,
-    FullPayload, Hash256, SignedBeaconBlock, SignedBlobSidecarList,
+    ForkName, FullPayload, FullPayloadMerge, Hash256, SignedBeaconBlock, SignedBlobSidecarList,
 };
 use warp::Rejection;

@ -308,18 +308,17 @@ pub async fn reconstruct_block<T: BeaconChainTypes>(

        // If the execution block hash is zero, use an empty payload.
        let full_payload_contents = if payload_header.block_hash() == ExecutionBlockHash::zero() {
-            let payload = FullPayload::default_at_fork(
-                chain
+            let fork_name = chain
                .spec
-                    .fork_name_at_epoch(block.slot().epoch(T::EthSpec::slots_per_epoch())),
-            )
-            .map_err(|e| {
-                warp_utils::reject::custom_server_error(format!(
-                    "Default payload construction error: {e:?}"
-                ))
-            })?
-            .into();
-            ProvenancedPayload::Local(FullPayloadContents::Payload(payload))
+                .fork_name_at_epoch(block.slot().epoch(T::EthSpec::slots_per_epoch()));
+            if fork_name == ForkName::Merge {
+                let payload: FullPayload<T::EthSpec> = FullPayloadMerge::default().into();
+                ProvenancedPayload::Local(FullPayloadContents::Payload(payload.into()))
+            } else {
+                Err(warp_utils::reject::custom_server_error(
+                    "Failed to construct full payload - block hash must be non-zero after Bellatrix.".to_string()
+                ))?
+            }
        // If we already have an execution payload with this transactions root cached, use it.
        } else if let Some(cached_payload) =
            el.get_payload_by_root(&payload_header.tree_hash_root())
--- a/beacon_node/network/src/sync/block_lookups/tests.rs
+++ b/beacon_node/network/src/sync/block_lookups/tests.rs
@ -17,7 +17,6 @@ use lighthouse_network::{NetworkGlobals, Request};
 use slot_clock::{ManualSlotClock, SlotClock, TestingSlotClock};
 use store::MemoryStore;
 use tokio::sync::mpsc;
-use types::beacon_block_body::to_block_kzg_commitments;
 use types::{
    map_fork_name, map_fork_name_with,
    test_utils::{SeedableRng, TestRandom, XorShiftRng},
@ -124,8 +123,7 @@ impl TestRig {
            for tx in Vec::from(transactions) {
                payload.execution_payload.transactions.push(tx).unwrap();
            }
-            message.body.blob_kzg_commitments =
-                to_block_kzg_commitments::<E>(bundle.commitments.clone());
+            message.body.blob_kzg_commitments = bundle.commitments.clone();

            let eth2::types::BlobsBundle {
                commitments,
--- a/common/eth2/src/types.rs
+++ b/common/eth2/src/types.rs
@ -12,7 +12,7 @@ use std::fmt::{self, Display};
 use std::str::{from_utf8, FromStr};
 use std::time::Duration;
 use tree_hash::TreeHash;
-use types::beacon_block_body::BuilderKzgCommitments;
+use types::beacon_block_body::KzgCommitments;
 use types::builder_bid::BlindedBlobsBundle;
 pub use types::*;

@ -1793,7 +1793,7 @@ pub struct ExecutionPayloadAndBlobs<E: EthSpec> {
 #[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize, Encode)]
 #[serde(bound = "E: EthSpec")]
 pub struct BlobsBundle<E: EthSpec> {
-    pub commitments: BuilderKzgCommitments<E>,
+    pub commitments: KzgCommitments<E>,
    pub proofs: KzgProofs<E>,
    #[serde(with = "ssz_types::serde_utils::list_of_hex_fixed_vec")]
    pub blobs: BlobsList<E>,
--- a/consensus/types/src/beacon_block_body.rs
+++ b/consensus/types/src/beacon_block_body.rs
@ -9,24 +9,9 @@ use superstruct::superstruct;
 use test_random_derive::TestRandom;
 use tree_hash_derive::TreeHash;

-//TODO: Remove this type and use `BlockBodyKzgCommitments` everywhere when this PR is merged:
-// https://github.com/ethereum/builder-specs/pull/87
-pub type BuilderKzgCommitments<T> = VariableList<KzgCommitment, <T as EthSpec>::MaxBlobsPerBlock>;
-pub type BlockBodyKzgCommitments<T> =
+pub type KzgCommitments<T> =
    VariableList<KzgCommitment, <T as EthSpec>::MaxBlobCommitmentsPerBlock>;

-pub fn to_block_kzg_commitments<E: EthSpec>(
-    commitments: BuilderKzgCommitments<E>,
-) -> BlockBodyKzgCommitments<E> {
-    commitments.to_vec().into()
-}
-
-pub fn from_block_kzg_commitments<E: EthSpec>(
-    commitments: &BlockBodyKzgCommitments<E>,
-) -> BuilderKzgCommitments<E> {
-    commitments.to_vec().into()
-}
-
 /// The body of a `BeaconChain` block, containing operations.
 ///
 /// This *superstruct* abstracts over the hard-fork.
@ -87,7 +72,7 @@ pub struct BeaconBlockBody<T: EthSpec, Payload: AbstractExecPayload<T> = FullPay
    pub bls_to_execution_changes:
        VariableList<SignedBlsToExecutionChange, T::MaxBlsToExecutionChanges>,
    #[superstruct(only(Deneb))]
-    pub blob_kzg_commitments: BlockBodyKzgCommitments<T>,
+    pub blob_kzg_commitments: KzgCommitments<T>,
    #[superstruct(only(Base, Altair))]
    #[ssz(skip_serializing, skip_deserializing)]
    #[tree_hash(skip_hashing)]
--- a/consensus/types/src/blob_sidecar.rs
+++ b/consensus/types/src/blob_sidecar.rs
@ -233,5 +233,5 @@ pub type BlindedBlobSidecarList<T> = SidecarList<T, BlindedBlobSidecar>;
 pub type FixedBlobSidecarList<T> =
    FixedVector<Option<Arc<BlobSidecar<T>>>, <T as EthSpec>::MaxBlobsPerBlock>;

-pub type BlobsList<T> = VariableList<Blob<T>, <T as EthSpec>::MaxBlobsPerBlock>;
-pub type BlobRootsList<T> = VariableList<Hash256, <T as EthSpec>::MaxBlobsPerBlock>;
+pub type BlobsList<T> = VariableList<Blob<T>, <T as EthSpec>::MaxBlobCommitmentsPerBlock>;
+pub type BlobRootsList<T> = VariableList<Hash256, <T as EthSpec>::MaxBlobCommitmentsPerBlock>;
--- a/consensus/types/src/builder_bid.rs
+++ b/consensus/types/src/builder_bid.rs
@ -1,4 +1,4 @@
-use crate::beacon_block_body::BuilderKzgCommitments;
+use crate::beacon_block_body::KzgCommitments;
 use crate::{
    BlobRootsList, ChainSpec, EthSpec, ExecutionPayloadHeaderCapella, ExecutionPayloadHeaderDeneb,
    ExecutionPayloadHeaderMerge, ExecutionPayloadHeaderRef, ForkName, ForkVersionDeserialize,
@ -15,7 +15,7 @@ use tree_hash_derive::TreeHash;
 #[derive(PartialEq, Debug, Default, Serialize, Deserialize, TreeHash, Clone, Encode)]
 #[serde(bound = "E: EthSpec")]
 pub struct BlindedBlobsBundle<E: EthSpec> {
-    pub commitments: BuilderKzgCommitments<E>,
+    pub commitments: KzgCommitments<E>,
    pub proofs: KzgProofs<E>,
    pub blob_roots: BlobRootsList<E>,
 }
--- a/consensus/types/src/lib.rs
+++ b/consensus/types/src/lib.rs
@ -208,7 +208,7 @@ pub type Address = H160;
 pub type ForkVersion = [u8; 4];
 pub type BLSFieldElement = Uint256;
 pub type Blob<T> = FixedVector<u8, <T as EthSpec>::BytesPerBlob>;
-pub type KzgProofs<T> = VariableList<KzgProof, <T as EthSpec>::MaxBlobsPerBlock>;
+pub type KzgProofs<T> = VariableList<KzgProof, <T as EthSpec>::MaxBlobCommitmentsPerBlock>;
 pub type VersionedHash = Hash256;
 pub type Hash64 = ethereum_types::H64;

--- a/consensus/types/src/payload.rs
+++ b/consensus/types/src/payload.rs
@ -398,8 +398,13 @@ impl<T: EthSpec> AbstractExecPayload<T> for FullPayload<T> {
            ForkName::Deneb => Ok(FullPayloadDeneb::default().into()),
        }
    }
-    fn default_blobs_at_fork(_fork_name: ForkName) -> Result<BlobsList<T>, Error> {
-        Ok(VariableList::default())
+    fn default_blobs_at_fork(fork_name: ForkName) -> Result<BlobsList<T>, Error> {
+        match fork_name {
+            ForkName::Base | ForkName::Altair | ForkName::Merge | ForkName::Capella => {
+                Err(Error::IncorrectStateVariant)
+            }
+            ForkName::Deneb => Ok(VariableList::default()),
+        }
    }
 }

@ -916,8 +921,13 @@ impl<T: EthSpec> AbstractExecPayload<T> for BlindedPayload<T> {
            ForkName::Deneb => Ok(BlindedPayloadDeneb::default().into()),
        }
    }
-    fn default_blobs_at_fork(_fork_name: ForkName) -> Result<BlobRootsList<T>, Error> {
-        Ok(VariableList::default())
+    fn default_blobs_at_fork(fork_name: ForkName) -> Result<BlobRootsList<T>, Error> {
+        match fork_name {
+            ForkName::Base | ForkName::Altair | ForkName::Merge | ForkName::Capella => {
+                Err(Error::IncorrectStateVariant)
+            }
+            ForkName::Deneb => Ok(VariableList::default()),
+        }
    }
 }

--- a/consensus/types/src/sidecar.rs
+++ b/consensus/types/src/sidecar.rs
@ -1,4 +1,4 @@
-use crate::beacon_block_body::BuilderKzgCommitments;
+use crate::beacon_block_body::KzgCommitments;
 use crate::test_utils::TestRandom;
 use crate::{
    AbstractExecPayload, BeaconBlock, BlindedBlobSidecar, BlindedBlobSidecarList, BlobRootsList,
@ -33,7 +33,7 @@ pub trait Sidecar<E: EthSpec>:
    fn build_sidecar<Payload: AbstractExecPayload<E>>(
        blob_items: Self::BlobItems,
        block: &BeaconBlock<E, Payload>,
-        expected_kzg_commitments: &BuilderKzgCommitments<E>,
+        expected_kzg_commitments: &KzgCommitments<E>,
        kzg_proofs: Vec<KzgProof>,
    ) -> Result<SidecarList<E, Self>, String>;
 }
@ -106,7 +106,7 @@ impl<E: EthSpec> Sidecar<E> for BlobSidecar<E> {
    fn build_sidecar<Payload: AbstractExecPayload<E>>(
        blobs: BlobsList<E>,
        block: &BeaconBlock<E, Payload>,
-        expected_kzg_commitments: &BuilderKzgCommitments<E>,
+        expected_kzg_commitments: &KzgCommitments<E>,
        kzg_proofs: Vec<KzgProof>,
    ) -> Result<SidecarList<E, Self>, String> {
        let beacon_block_root = block.canonical_root();
@ -152,7 +152,7 @@ impl<E: EthSpec> Sidecar<E> for BlindedBlobSidecar {
    fn build_sidecar<Payload: AbstractExecPayload<E>>(
        blob_roots: BlobRootsList<E>,
        block: &BeaconBlock<E, Payload>,
-        expected_kzg_commitments: &BuilderKzgCommitments<E>,
+        expected_kzg_commitments: &KzgCommitments<E>,
        kzg_proofs: Vec<KzgProof>,
    ) -> Result<SidecarList<E, BlindedBlobSidecar>, String> {
        let beacon_block_root = block.canonical_root();
--- a/scripts/local_testnet/README.md
+++ b/scripts/local_testnet/README.md
@ -128,3 +128,16 @@ Update the genesis time to now using:

 > Note: you probably want to just rerun `./start_local_testnet.sh` to start over
 > but this is another option.
+
+### Testing builder flow
+
+1. Add builder URL to `BN_ARGS` in `./var.env`, e.g. `--builder http://localhost:8650`. Some mock builder server options: 
+    - [`mock-relay`](https://github.com/realbigsean/mock-relay)
+    - [`dummy-builder`](https://github.com/michaelsproul/dummy_builder)
+2. (Optional) Add `--always-prefer-builder-payload` to `BN_ARGS`.
+3. The above mock builders do not support non-mainnet presets as of now, and will require setting `SECONDS_PER_SLOT` and `SECONDS_PER_ETH1_BLOCK` to `12` in `./vars.env`. 
+4. Start the testnet with the following command (the `-p` flag enables the validator client `--builder-proposals` flag:
+    ```bash
+    ./start_local_testnet.sh -p genesis.json
+    ```
+5. Block production using builder flow will start at epoch 4.
--- a/scripts/local_testnet/beacon_node.sh
+++ b/scripts/local_testnet/beacon_node.sh
@ -63,4 +63,5 @@ exec $lighthouse_binary \
 	--disable-packet-filter \
 	--target-peers $((BN_COUNT - 1)) \
  --execution-endpoint $execution_endpoint \
-  --execution-jwt $execution_jwt
+  --execution-jwt $execution_jwt \
+  $BN_ARGS
--- a/scripts/local_testnet/setup.sh
+++ b/scripts/local_testnet/setup.sh
@ -47,6 +47,6 @@ lcli \
 	insecure-validators \
 	--count $VALIDATOR_COUNT \
 	--base-dir $DATADIR \
-	--node-count $BN_COUNT
+	--node-count $VC_COUNT

 echo Validators generated with keystore passwords at $DATADIR.
--- a/scripts/local_testnet/vars.env
+++ b/scripts/local_testnet/vars.env
@ -61,5 +61,8 @@ SECONDS_PER_ETH1_BLOCK=1
 # Proposer score boost percentage
 PROPOSER_SCORE_BOOST=40

+# Command line arguments for beacon node client
+BN_ARGS=""
+
 # Command line arguments for validator client
 VC_ARGS=""
--- a/scripts/tests/vars.env
+++ b/scripts/tests/vars.env
@ -58,5 +58,8 @@ SECONDS_PER_ETH1_BLOCK=1
 # Proposer score boost percentage
 PROPOSER_SCORE_BOOST=70

+# Command line arguments for beacon node client
+BN_ARGS=""
+
 # Enable doppelganger detection
 VC_ARGS=" --enable-doppelganger-protection "