feat(client): Interop consolidation sub-problem (#913)

bin/client/src/interop/consolidate.rs

@@ -1 +1,70 @@
 //! Consolidation phase of the interop proof program.
+
+use super::FaultProofProgramError;
+use alloc::{sync::Arc, vec::Vec};
+use core::fmt::Debug;
+use kona_interop::MessageGraph;
+use kona_preimage::{HintWriterClient, PreimageOracleClient};
+use kona_proof::CachingOracle;
+use kona_proof_interop::{BootInfo, OracleInteropProvider, PreState};
+use revm::primitives::HashMap;
+use tracing::info;
+
+/// Executes the consolidation phase of the interop proof with the given [PreimageOracleClient] and
+/// [HintWriterClient].
+///
+/// This phase is responsible for checking the dependencies between [OptimisticBlock]s in the
+/// superchain and ensuring that all dependencies are satisfied.
+///
+/// [OptimisticBlock]: kona_proof_interop::OptimisticBlock
+pub(crate) async fn consolidate_dependencies<P, H>(
+    oracle: Arc<CachingOracle<P, H>>,
+    boot: BootInfo,
+    pre: PreState,
+) -> Result<(), FaultProofProgramError>
+where
+    P: PreimageOracleClient + Send + Sync + Debug + Clone,
+    H: HintWriterClient + Send + Sync + Debug + Clone,
+{
+    let provider = OracleInteropProvider::new(oracle, pre.clone());
+
+    info!(target: "client_interop", "Deriving local-safe headers from prestate");
+
+    // Ensure that the pre-state is a transition state.
+    let PreState::TransitionState(ref transition_state) = pre else {
+        return Err(FaultProofProgramError::StateTransitionFailed);
+    };
+
+    let block_hashes = transition_state
+        .pending_progress
+        .iter()
+        .zip(transition_state.pre_state.output_roots.iter())
+        .map(|(optimistic_block, pre_state)| (pre_state.chain_id, optimistic_block.block_hash))
+        .collect::<HashMap<_, _>>();
+
+    let mut headers = Vec::with_capacity(block_hashes.len());
+    for (chain_id, block_hash) in block_hashes {
+        let header = provider.header_by_hash(chain_id, block_hash).await?;
+        headers.push((chain_id, header.seal(block_hash)));
+    }
+
+    info!(target: "client_interop", "Loaded {} local-safe headers", headers.len());
+
+    // TODO: Re-execution w/ bad blocks. Not complete, we just panic if any deps are invalid atm.
+    let graph = MessageGraph::derive(headers.as_slice(), provider).await.unwrap();
+    graph.resolve().await.unwrap();
+
+    // Transition to the Super Root at the next timestamp.
+    //
+    // TODO: This won't work if we replace blocks, `transition` doesn't allow replacement of pending
+    // progress just yet.
+    let post = pre.transition(None).ok_or(FaultProofProgramError::StateTransitionFailed)?;
+    let post_commitment = post.hash();
+
+    // Ensure that the post-state matches the claimed post-state.
+    if post_commitment != boot.claimed_post_state {
+        return Err(FaultProofProgramError::InvalidClaim(boot.claimed_post_state, post_commitment));
+    }
+
+    Ok(())
+}

bin/client/src/interop/mod.rs

@@ -3,6 +3,7 @@
 use alloc::sync::Arc;
 use alloy_primitives::B256;
 use alloy_rlp::Decodable;
+use consolidate::consolidate_dependencies;
 use core::fmt::Debug;
 use kona_driver::DriverError;
 use kona_executor::{ExecutorError, KonaHandleRegister};
@@ -11,6 +12,7 @@ use kona_proof::{errors::OracleProviderError, l2::OracleL2ChainProvider, Caching
 use kona_proof_interop::{BootInfo, PreState, INVALID_TRANSITION_HASH, TRANSITION_STATE_MAX_STEPS};
 use thiserror::Error;
 use tracing::{error, info};
+use transition::sub_transition;
 use util::read_raw_pre_state;
 
 pub(crate) mod consolidate;
@@ -66,7 +68,7 @@ where
         }
     };
 
-    // If the pre state is invalid, short-circuit and check if the post-state is also invalid.
+    // If the pre state is invalid, short-circuit and check if the post-state claim is also invalid.
     if boot.agreed_pre_state == INVALID_TRANSITION_HASH &&
         boot.claimed_post_state == INVALID_TRANSITION_HASH
     {
@@ -81,15 +83,15 @@ where
     match pre {
         PreState::SuperRoot(_) => {
             // If the pre-state is a super root, the first sub-problem is always selected.
-            transition::sub_transition(oracle, handle_register, boot, pre).await
+            sub_transition(oracle, handle_register, boot, pre).await
         }
         PreState::TransitionState(ref transition_state) => {
             // If the pre-state is a transition state, the sub-problem is selected based on the
             // current step.
             if transition_state.step < TRANSITION_STATE_MAX_STEPS {
-                transition::sub_transition(oracle, handle_register, boot, pre).await
+                sub_transition(oracle, handle_register, boot, pre).await
             } else {
-                unimplemented!("Consolidation step")
+                consolidate_dependencies(oracle, boot, pre).await
             }
         }
     }

bin/client/src/interop/transition.rs

@@ -42,7 +42,7 @@ where
         if transition_state.step >= transition_state.pre_state.output_roots.len() as u64 {
             info!(
                 target: "interop_client",
-                "No state transition required, transition state is already saturated."
+                "No derivation/execution required, transition state is already saturated."
             );
 
             return transition_and_check(pre, None, boot.claimed_post_state);

bin/host/src/interop/fetcher.rs

@@ -256,19 +256,31 @@ where
             }
             HintType::L2BlockHeader => {
                 // Validate the hint data length.
-                if hint_data.len() != 32 {
+                if hint_data.len() < 32 || hint_data.len() > 40 {
                     anyhow::bail!("Invalid hint data length: {}", hint_data.len());
                 }
 
                 // Fetch the raw header from the L2 chain provider.
-                let hash: B256 = hint_data
+                let hash: B256 = hint_data[0..32]
                     .as_ref()
                     .try_into()
                     .map_err(|e| anyhow!("Failed to convert bytes to B256: {e}"))?;
+
+                let active_l2_chain_id = if hint_data.len() == 40 {
+                    u64::from_be_bytes(
+                        hint_data[32..40]
+                            .as_ref()
+                            .try_into()
+                            .map_err(|e| anyhow!("Failed to convert bytes to u64: {e}"))?,
+                    )
+                } else {
+                    self.active_l2_chain_id
+                };
+
                 let raw_header: Bytes = self
                     .l2_providers
-                    .get(&self.active_l2_chain_id)
-                    .ok_or(anyhow!("No active L2 chain ID"))?
+                    .get(&active_l2_chain_id)
+                    .ok_or(anyhow!("No provider for active L2 chain ID"))?
                     .client()
                     .request("debug_getRawHeader", [hash])
                     .await
@@ -322,6 +334,35 @@ where
                     _ => anyhow::bail!("Only BlockTransactions::Hashes are supported."),
                 };
             }
+            HintType::L2Receipts => {
+                // Validate the hint data length.
+                if hint_data.len() != 40 {
+                    anyhow::bail!("Invalid hint data length: {}", hint_data.len());
+                }
+
+                // Fetch the receipts from the L1 chain provider and store the receipts within the
+                // key-value store.
+                let hash: B256 = hint_data[0..32]
+                    .as_ref()
+                    .try_into()
+                    .map_err(|e| anyhow!("Failed to convert bytes to B256: {e}"))?;
+                let chain_id = u64::from_be_bytes(
+                    hint_data[32..40]
+                        .as_ref()
+                        .try_into()
+                        .map_err(|e| anyhow!("Failed to convert bytes to u64: {e}"))?,
+                );
+
+                let raw_receipts: Vec<Bytes> = self
+                    .l2_providers
+                    .get(&chain_id)
+                    .ok_or(anyhow!("Provider for chain ID {chain_id} not found"))?
+                    .client()
+                    .request("debug_getRawReceipts", [hash])
+                    .await
+                    .map_err(|e| anyhow!(e))?;
+                self.store_trie_nodes(raw_receipts.as_slice()).await?;
+            }
             HintType::L2Code => {
                 // geth hashdb scheme code hash key prefix
                 const CODE_PREFIX: u8 = b'c';

crates/interop/src/errors.rs

@@ -1,5 +1,6 @@
 //! Error types for the `kona-interop` crate.
 
+use crate::InteropProvider;
 use alloc::vec::Vec;
 use alloy_primitives::{Address, B256};
 use thiserror::Error;
@@ -8,7 +9,7 @@ use thiserror::Error;
 ///
 /// [MessageGraph]: crate::MessageGraph
 #[derive(Debug, Clone, PartialEq, Eq, Error)]
-pub enum MessageGraphError {
+pub enum MessageGraphError<E> {
     /// Dependency set is impossibly empty
     #[error("Dependency set is impossibly empty")]
     EmptyDependencySet,
@@ -32,39 +33,28 @@ pub enum MessageGraphError {
     InvalidMessages(Vec<u64>),
     /// Interop provider error
     #[error("Interop provider: {0}")]
-    InteropProviderError(#[from] InteropProviderError),
+    InteropProviderError(#[from] E),
 }
 
 /// A [Result] alias for the [MessageGraphError] type.
-pub type MessageGraphResult<T> = core::result::Result<T, MessageGraphError>;
-
-/// An error type for the [InteropProvider] trait.
-///
-/// [InteropProvider]: crate::InteropProvider
-#[derive(Debug, Clone, PartialEq, Eq, Error)]
-pub enum InteropProviderError {
-    /// Unknown Chain ID
-    #[error("Unknown Chain ID")]
-    UnknownChainId,
-    /// Not found
-    #[error("Not found")]
-    NotFound,
-}
-
-/// A [Result] alias for the [InteropProviderError] type.
-pub type InteropProviderResult<T> = core::result::Result<T, InteropProviderError>;
+#[allow(type_alias_bounds)]
+pub type MessageGraphResult<T, P: InteropProvider> =
+    core::result::Result<T, MessageGraphError<P::Error>>;
 
 /// An error type for the [SuperRoot] struct's serialization and deserialization.
 ///
 /// [SuperRoot]: crate::SuperRoot
-#[derive(Debug, Clone, PartialEq, Eq, Error)]
+#[derive(Debug, Clone, Error)]
 pub enum SuperRootError {
     /// Invalid super root version byte
     #[error("Invalid super root version byte")]
     InvalidVersionByte,
     /// Unexpected encoded super root length
     #[error("Unexpected encoded super root length")]
     UnexpectedLength,
+    /// Slice conversion error
+    #[error("Slice conversion error: {0}")]
+    SliceConversionError(#[from] core::array::TryFromSliceError),
 }
 
 /// A [Result] alias for the [SuperRootError] type.

crates/interop/src/graph.rs

@@ -47,7 +47,10 @@ where
     /// blocks and searching for [ExecutingMessage]s.
     ///
     /// [ExecutingMessage]: crate::ExecutingMessage
-    pub async fn derive(blocks: &[(u64, Sealed<Header>)], provider: P) -> MessageGraphResult<Self> {
+    pub async fn derive(
+        blocks: &[(u64, Sealed<Header>)],
+        provider: P,
+    ) -> MessageGraphResult<Self, P> {
         info!(
             target: "message-graph",
             "Deriving message graph from {} blocks.",
@@ -84,7 +87,7 @@ where
     }
 
     /// Checks the validity of all messages within the graph.
-    pub async fn resolve(mut self) -> MessageGraphResult<()> {
+    pub async fn resolve(mut self) -> MessageGraphResult<(), P> {
         info!(
             target: "message-graph",
             "Checking the message graph for invalid messages."
@@ -120,7 +123,7 @@ where
     /// Attempts to remove as many edges from the graph as possible by resolving the dependencies
     /// of each message. If a message cannot be resolved, it is considered invalid. After this
     /// function is called, any outstanding messages are invalid.
-    async fn reduce(&mut self) -> MessageGraphResult<()> {
+    async fn reduce(&mut self) -> MessageGraphResult<(), P> {
         // Create a new vector to store invalid edges
         let mut invalid_messages = Vec::with_capacity(self.messages.len());
 
@@ -155,7 +158,7 @@ where
     async fn check_single_dependency(
         &self,
         message: &EnrichedExecutingMessage,
-    ) -> MessageGraphResult<()> {
+    ) -> MessageGraphResult<(), P> {
         // ChainID Invariant: The chain id of the initiating message MUST be in the dependency set
         // This is enforced implicitly by the graph constructor and the provider.
 

crates/interop/src/lib.rs

@@ -25,10 +25,7 @@ mod traits;
 pub use traits::InteropProvider;
 
 mod errors;
-pub use errors::{
-    InteropProviderError, InteropProviderResult, MessageGraphError, MessageGraphResult,
-    SuperRootError, SuperRootResult,
-};
+pub use errors::{MessageGraphError, MessageGraphResult, SuperRootError, SuperRootResult};
 
 mod super_root;
 pub use super_root::{OutputRootWithChain, SuperRoot};

crates/interop/src/super_root.rs

@@ -43,7 +43,7 @@ impl SuperRoot {
         if buf.len() < 8 {
             return Err(SuperRootError::UnexpectedLength);
         }
-        let timestamp = u64::from_be_bytes(buf[0..8].try_into().unwrap());
+        let timestamp = u64::from_be_bytes(buf[0..8].try_into()?);
         buf.advance(8);
 
         let mut output_roots = Vec::new();
@@ -52,7 +52,7 @@ impl SuperRoot {
                 return Err(SuperRootError::UnexpectedLength);
             }
 
-            let chain_id = U256::from_be_bytes::<32>(buf[0..32].try_into().unwrap());
+            let chain_id = U256::from_be_bytes::<32>(buf[0..32].try_into()?);
             buf.advance(32);
             let output_root = B256::from_slice(&buf[0..32]);
             buf.advance(32);
@@ -129,37 +129,37 @@ mod test {
     #[test]
     fn test_super_root_empty_buf() {
         let buf: Vec<u8> = Vec::new();
-        assert_eq!(
+        assert!(matches!(
             SuperRoot::decode(&mut buf.as_slice()).unwrap_err(),
             SuperRootError::UnexpectedLength
-        );
+        ));
     }
 
     #[test]
     fn test_super_root_invalid_version() {
         let buf = vec![0xFF];
-        assert_eq!(
+        assert!(matches!(
             SuperRoot::decode(&mut buf.as_slice()).unwrap_err(),
             SuperRootError::InvalidVersionByte
-        );
+        ));
     }
 
     #[test]
     fn test_super_root_invalid_length_at_timestamp() {
         let buf = vec![SUPER_ROOT_VERSION, 0x00];
-        assert_eq!(
+        assert!(matches!(
             SuperRoot::decode(&mut buf.as_slice()).unwrap_err(),
             SuperRootError::UnexpectedLength
-        );
+        ));
     }
 
     #[test]
     fn test_super_root_invalid_length_malformed_output_roots() {
         let buf = [&[SUPER_ROOT_VERSION], 64u64.to_be_bytes().as_ref(), &[0xbe, 0xef]].concat();
-        assert_eq!(
+        assert!(matches!(
             SuperRoot::decode(&mut buf.as_slice()).unwrap_err(),
             SuperRootError::UnexpectedLength
-        );
+        ));
     }
 
     #[test]