checkpoint sync without alignment

beacon_node/beacon_chain/src/builder.rs

@@ -419,23 +419,14 @@ where
         let weak_subj_block_root = weak_subj_block.canonical_root();
         let weak_subj_state_root = weak_subj_block.state_root();
 
-        // Check that the given block lies on an epoch boundary. Due to the database only storing
+        // Check that the given state lies on an epoch boundary. Due to the database only storing
         // full states on epoch boundaries and at restore points it would be difficult to support
         // starting from a mid-epoch state.
         if weak_subj_slot % TEthSpec::slots_per_epoch() != 0 {
             return Err(format!(
-                "Checkpoint block at slot {} is not aligned to epoch start. \
-                 Please supply an aligned checkpoint with block.slot % 32 == 0",
-                weak_subj_block.slot(),
-            ));
-        }
-
-        // Check that the block and state have consistent slots and state roots.
-        if weak_subj_state.slot() != weak_subj_block.slot() {
-            return Err(format!(
-                "Slot of snapshot block ({}) does not match snapshot state ({})",
-                weak_subj_block.slot(),
-                weak_subj_state.slot(),
+                "Checkpoint state at slot {} is not aligned to epoch start. \
+                 Please supply an aligned checkpoint with state.slot % 32 == 0",
+                weak_subj_slot,
             ));
         }
 
@@ -508,13 +499,12 @@ where
         let fc_store = BeaconForkChoiceStore::get_forkchoice_store(store, &snapshot)
             .map_err(|e| format!("Unable to initialize fork choice store: {e:?}"))?;
 
-        let current_slot = Some(snapshot.beacon_block.slot());
         let fork_choice = ForkChoice::from_anchor(
             fc_store,
             snapshot.beacon_block_root,
             &snapshot.beacon_block,
             &snapshot.beacon_state,
-            current_slot,
+            Some(weak_subj_slot),
             &self.spec,
         )
         .map_err(|e| format!("Unable to initialize ForkChoice: {:?}", e))?;

beacon_node/client/src/builder.rs

@@ -28,6 +28,7 @@ use network::{NetworkConfig, NetworkSenders, NetworkService};
 use slasher::Slasher;
 use slasher_service::SlasherService;
 use slog::{debug, info, warn, Logger};
+use state_processing::per_slot_processing;
 use std::net::TcpListener;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
@@ -347,8 +348,8 @@ where
                 };
 
                 debug!(context.log(), "Downloading finalized block");
-                // Find a suitable finalized block on an epoch boundary.
-                let mut block = remote
+                // Find a suitable finalized block.
+                let block = remote
                     .get_beacon_blocks_ssz::<TEthSpec>(BlockId::Finalized, &spec)
                     .await
                     .map_err(|e| match e {
@@ -363,42 +364,13 @@ where
 
                 debug!(context.log(), "Downloaded finalized block");
 
-                let mut block_slot = block.slot();
-
-                while block.slot() % slots_per_epoch != 0 {
-                    block_slot = (block_slot / slots_per_epoch - 1) * slots_per_epoch;
-
-                    debug!(
-                        context.log(),
-                        "Searching for aligned checkpoint block";
-                        "block_slot" => block_slot
-                    );
-
-                    if let Some(found_block) = remote
-                        .get_beacon_blocks_ssz::<TEthSpec>(BlockId::Slot(block_slot), &spec)
-                        .await
-                        .map_err(|e| {
-                            format!("Error fetching block at slot {}: {:?}", block_slot, e)
-                        })?
-                    {
-                        block = found_block;
-                    }
-                }
-
-                debug!(
-                    context.log(),
-                    "Downloaded aligned finalized block";
-                    "block_root" => ?block.canonical_root(),
-                    "block_slot" => block.slot(),
-                );
-
                 let state_root = block.state_root();
                 debug!(
                     context.log(),
                     "Downloading finalized state";
                     "state_root" => ?state_root
                 );
-                let state = remote
+                let mut state = remote
                     .get_debug_beacon_states_ssz::<TEthSpec>(StateId::Root(state_root), &spec)
                     .await
                     .map_err(|e| {
@@ -413,13 +385,19 @@ where
 
                 debug!(context.log(), "Downloaded finalized state");
 
+                while state.slot() % slots_per_epoch != 0 {
+                    per_slot_processing(&mut state, Some(state_root), &spec)
+                        .map_err(|e| format!("Error advancing state: {:?}", e))?;
+                }
+
                 let genesis_state = BeaconState::from_ssz_bytes(&genesis_state_bytes, &spec)
                     .map_err(|e| format!("Unable to parse genesis state SSZ: {:?}", e))?;
 
                 info!(
                     context.log(),
                     "Loaded checkpoint block and state";
-                    "slot" => block.slot(),
+                    "block_slot" => block.slot(),
+                    "state_slot" => state.slot(),
                     "block_root" => ?block.canonical_root(),
                     "state_root" => ?state_root,
                 );

consensus/fork_choice/src/fork_choice.rs

@@ -352,7 +352,7 @@ where
         spec: &ChainSpec,
     ) -> Result<Self, Error<T::Error>> {
         // Sanity check: the anchor must lie on an epoch boundary.
-        if anchor_block.slot() % E::slots_per_epoch() != 0 {
+        if anchor_state.slot() % E::slots_per_epoch() != 0 {
             return Err(Error::InvalidAnchor {
                 block_slot: anchor_block.slot(),
                 state_slot: anchor_state.slot(),
@@ -388,6 +388,7 @@ where
         let current_slot = current_slot.unwrap_or_else(|| fc_store.get_current_slot());
 
         let proto_array = ProtoArrayForkChoice::new::<E>(
+            current_slot,
             finalized_block_slot,
             finalized_block_state_root,
             *fc_store.justified_checkpoint(),

consensus/proto_array/src/fork_choice_test_definition.rs

@@ -80,6 +80,7 @@ impl ForkChoiceTestDefinition {
         let junk_shuffling_id =
             AttestationShufflingId::from_components(Epoch::new(0), Hash256::zero());
         let mut fork_choice = ProtoArrayForkChoice::new::<MainnetEthSpec>(
+            self.finalized_block_slot,
             self.finalized_block_slot,
             Hash256::zero(),
             self.justified_checkpoint,

consensus/proto_array/src/proto_array_fork_choice.rs

@@ -345,6 +345,7 @@ pub struct ProtoArrayForkChoice {
 impl ProtoArrayForkChoice {
     #[allow(clippy::too_many_arguments)]
     pub fn new<E: EthSpec>(
+        current_slot: Slot,
         finalized_block_slot: Slot,
         finalized_block_state_root: Hash256,
         justified_checkpoint: Checkpoint,
@@ -380,7 +381,7 @@ impl ProtoArrayForkChoice {
         };
 
         proto_array
-            .on_block::<E>(block, finalized_block_slot)
+            .on_block::<E>(block, current_slot)
             .map_err(|e| format!("Failed to add finalized block to proto_array: {:?}", e))?;
 
         Ok(Self {
@@ -1108,6 +1109,7 @@ mod test_compute_deltas {
         };
 
         let mut fc = ProtoArrayForkChoice::new::<MainnetEthSpec>(
+            genesis_slot,
             genesis_slot,
             junk_state_root,
             genesis_checkpoint,