Fix parent_beacon_block_root during proposer prep (#4703)

* Fix `parent_beacon_block_root` during prep/reorg

* Fix another bug and add tests

* Remove overzealous payload attributes check

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -236,9 +236,12 @@ pub enum ProduceBlockVerification {
 pub struct PrePayloadAttributes {
     pub proposer_index: u64,
     pub prev_randao: Hash256,
+    /// The block number of the block being built upon (same block as fcU `headBlockHash`).
+    ///
     /// The parent block number is not part of the payload attributes sent to the EL, but *is*
     /// sent to builders via SSE.
     pub parent_block_number: u64,
+    /// The block root of the block being built upon (same block as fcU `headBlockHash`).
     pub parent_beacon_block_root: Hash256,
 }
 
@@ -4111,10 +4114,10 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         let proposal_epoch = proposal_slot.epoch(T::EthSpec::slots_per_epoch());
 
         let head_block_root = cached_head.head_block_root();
-        let parent_beacon_block_root = cached_head.parent_block_root();
+        let head_parent_block_root = cached_head.parent_block_root();
 
         // The proposer head must be equal to the canonical head or its parent.
-        if proposer_head != head_block_root && proposer_head != parent_beacon_block_root {
+        if proposer_head != head_block_root && proposer_head != head_parent_block_root {
             warn!(
                 self.log,
                 "Unable to compute payload attributes";
@@ -4193,7 +4196,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
 
         // Get the `prev_randao` and parent block number.
         let head_block_number = cached_head.head_block_number()?;
-        let (prev_randao, parent_block_number) = if proposer_head == parent_beacon_block_root {
+        let (prev_randao, parent_block_number) = if proposer_head == head_parent_block_root {
             (
                 cached_head.parent_random()?,
                 head_block_number.saturating_sub(1),
@@ -4206,7 +4209,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
             proposer_index,
             prev_randao,
             parent_block_number,
-            parent_beacon_block_root,
+            parent_beacon_block_root: proposer_head,
         }))
     }
 
@@ -4589,8 +4592,13 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         let prepare_payload_handle = match &state {
             BeaconState::Base(_) | BeaconState::Altair(_) => None,
             BeaconState::Merge(_) | BeaconState::Capella(_) | BeaconState::Deneb(_) => {
-                let prepare_payload_handle =
-                    get_execution_payload(self.clone(), &state, proposer_index, builder_params)?;
+                let prepare_payload_handle = get_execution_payload(
+                    self.clone(),
+                    &state,
+                    parent_root,
+                    proposer_index,
+                    builder_params,
+                )?;
                 Some(prepare_payload_handle)
             }
         };

beacon_node/beacon_chain/src/execution_payload.rs

@@ -404,6 +404,7 @@ pub fn get_execution_payload<
 >(
     chain: Arc<BeaconChain<T>>,
     state: &BeaconState<T::EthSpec>,
+    parent_block_root: Hash256,
     proposer_index: u64,
     builder_params: BuilderParams,
 ) -> Result<PreparePayloadHandle<T::EthSpec, Payload>, BlockProductionError> {
@@ -426,10 +427,10 @@ pub fn get_execution_payload<
         &BeaconState::Base(_) | &BeaconState::Altair(_) => None,
     };
     let parent_beacon_block_root = match state {
-        &BeaconState::Deneb(_) => Some(state.latest_block_header().canonical_root()),
-        &BeaconState::Merge(_) | &BeaconState::Capella(_) => None,
+        BeaconState::Deneb(_) => Some(parent_block_root),
+        BeaconState::Merge(_) | BeaconState::Capella(_) => None,
         // These shouldn't happen but they're here to make the pattern irrefutable
-        &BeaconState::Base(_) | &BeaconState::Altair(_) => None,
+        BeaconState::Base(_) | BeaconState::Altair(_) => None,
     };
 
     // Spawn a task to obtain the execution payload from the EL via a series of async calls. The

beacon_node/beacon_chain/src/test_utils.rs

@@ -890,32 +890,10 @@ where
             | SignedBeaconBlock::Altair(_)
             | SignedBeaconBlock::Merge(_)
             | SignedBeaconBlock::Capella(_) => (signed_block, None),
-            SignedBeaconBlock::Deneb(_) => {
-                if let Some(blobs) = maybe_blob_sidecars {
-                    let signed_blobs: SignedSidecarList<E, BlobSidecar<E>> = Vec::from(blobs)
-                        .into_iter()
-                        .map(|blob| {
-                            blob.sign(
-                                &self.validator_keypairs[proposer_index].sk,
-                                &state.fork(),
-                                state.genesis_validators_root(),
-                                &self.spec,
-                            )
-                        })
-                        .collect::<Vec<_>>()
-                        .into();
-                    let mut guard = self.blob_signature_cache.write();
-                    for blob in &signed_blobs {
-                        guard.insert(
-                            BlobSignatureKey::new(blob.message.block_root, blob.message.index),
-                            blob.signature.clone(),
-                        );
-                    }
-                    (signed_block, Some(signed_blobs))
-                } else {
-                    (signed_block, None)
-                }
-            }
+            SignedBeaconBlock::Deneb(_) => (
+                signed_block,
+                maybe_blob_sidecars.map(|blobs| self.sign_blobs(blobs, &state, proposer_index)),
+            ),
         };
 
         (block_contents, state)
@@ -1037,6 +1015,35 @@ where
         )
     }
 
+    /// Sign blobs, and cache their signatures.
+    pub fn sign_blobs(
+        &self,
+        blobs: BlobSidecarList<E>,
+        state: &BeaconState<E>,
+        proposer_index: usize,
+    ) -> SignedSidecarList<E, BlobSidecar<E>> {
+        let signed_blobs: SignedSidecarList<E, BlobSidecar<E>> = Vec::from(blobs)
+            .into_iter()
+            .map(|blob| {
+                blob.sign(
+                    &self.validator_keypairs[proposer_index].sk,
+                    &state.fork(),
+                    state.genesis_validators_root(),
+                    &self.spec,
+                )
+            })
+            .collect::<Vec<_>>()
+            .into();
+        let mut guard = self.blob_signature_cache.write();
+        for blob in &signed_blobs {
+            guard.insert(
+                BlobSignatureKey::new(blob.message.block_root, blob.message.index),
+                blob.signature.clone(),
+            );
+        }
+        signed_blobs
+    }
+
     /// Produces an "unaggregated" attestation for the given `slot` and `index` that attests to
     /// `beacon_block_root`. The provided `state` should match the `block.state_root` for the
     /// `block` identified by `beacon_block_root`.
@@ -1940,7 +1947,7 @@ where
             )
             .await?
             .try_into()
-            .unwrap();
+            .expect("block blobs are available");
         self.chain.recompute_head_at_current_slot().await;
         Ok(block_hash)
     }