WEB3-315: feat: Add EVM Event support to Steel

Cargo.toml

@@ -26,8 +26,10 @@ risc0-binfmt = { git = "https://github.com/risc0/risc0", branch = "main", defaul
 
 # Alloy guest dependencies
 alloy-consensus = { version = "0.9" }
+alloy-eips = { version = "0.9" }
 alloy-rlp = { version = "0.3.8" }
 alloy-primitives = { version = "0.8.16" }
+alloy-rpc-types = { version = "0.9" }
 alloy-sol-types = { version = "0.8.16" }
 
 # OP Steel

crates/op-steel/Cargo.toml

@@ -33,3 +33,4 @@ risc0-op-steel = { workspace = true, features = ["host"] }
 [features]
 default = []
 host = ["dep:alloy", "dep:tokio", "dep:url", "risc0-steel/host", "alloy-primitives/rand"]
+unstable-event = []

crates/op-steel/src/optimism/mod.rs

@@ -98,6 +98,16 @@ impl EvmBlockHeader for OpBlockHeader {
     fn state_root(&self) -> &B256 {
         &self.0.inner().state_root
     }
+    #[cfg(feature = "unstable-event")]
+    #[inline]
+    fn receipts_root(&self) -> &B256 {
+        &self.0.inner().receipts_root
+    }
+    #[cfg(feature = "unstable-event")]
+    #[inline]
+    fn logs_bloom(&self) -> &alloy_primitives::Bloom {
+        &self.0.inner().logs_bloom
+    }
 
     #[inline]
     fn fill_block_env(&self, blk_env: &mut BlockEnv) {

crates/steel/CHANGELOG.md

@@ -4,8 +4,11 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
-<!-- TODO: Add link when release is finished -->
-## [1.3.0]
+### ⚡️ Features
+
+- Introduce the capability to query Ethereum events. The new `Event` allows to query events of a specific type in Steel. Its usage is very similar to the existing `Contract`, during the preflight step and in the guest. This functionality is currently marked unstable and must be enabled using the `unstable-event` feature.
+
+## [1.3.0](https://github.com/risc0/risc0-ethereum/releases/tag/v1.3.0)
 
 ### ⚡️ Features
 

crates/steel/Cargo.toml

@@ -15,8 +15,10 @@ rustdoc-args = ["--cfg", "docsrs"]
 [dependencies]
 alloy = { workspace = true, optional = true, features = ["full"] }
 alloy-consensus = { workspace = true }
+alloy-eips = { workspace = true }
 alloy-primitives = { workspace = true, features = ["rlp", "serde"] }
 alloy-rlp = { workspace = true }
+alloy-rpc-types = { workspace = true }
 alloy-sol-types = { workspace = true }
 alloy-trie = { workspace = true, features = ["serde"] }
 anyhow = { workspace = true }
@@ -50,5 +52,6 @@ host = [
     "dep:tokio",
     "dep:url",
 ]
+unstable-event = []
 unstable-history = []
 unstable-verifier = []

crates/steel/src/block.rs

@@ -13,10 +13,11 @@
 // limitations under the License.
 
 use crate::{
-    config::ChainSpec, state::StateDb, BlockHeaderCommit, Commitment, CommitmentVersion,
-    EvmBlockHeader, EvmEnv, GuestEvmEnv, MerkleTrie,
+    config::ChainSpec, serde::Eip2718Wrapper, state::StateDb, BlockHeaderCommit, Commitment,
+    CommitmentVersion, EvmBlockHeader, EvmEnv, GuestEvmEnv, MerkleTrie,
 };
 use ::serde::{Deserialize, Serialize};
+use alloy_consensus::ReceiptEnvelope;
 use alloy_primitives::{map::HashMap, Bytes, Sealed, B256};
 
 /// Input committing to the corresponding execution block hash.
@@ -27,6 +28,7 @@ pub struct BlockInput<H> {
     storage_tries: Vec<MerkleTrie>,
     contracts: Vec<Bytes>,
     ancestors: Vec<H>,
+    receipts: Option<Vec<Eip2718Wrapper<ReceiptEnvelope>>>,
 }
 
 /// Implement [BlockHeaderCommit] for the unit type.
@@ -72,11 +74,38 @@ impl<H: EvmBlockHeader> BlockInput<H> {
             previous_header = ancestor;
         }
 
+        #[cfg(not(feature = "unstable-event"))]
+        // there must not be any receipts, if events are not supported
+        let logs = {
+            assert!(self.receipts.is_none(), "Receipts not supported");
+            None
+        };
+        #[cfg(feature = "unstable-event")]
+        // verify the root hash of the included receipts and extract their logs
+        let logs = self.receipts.map(|receipts| {
+            let root = alloy_trie::root::ordered_trie_root_with_encoder(&receipts, |r, out| {
+                alloy_eips::eip2718::Encodable2718::encode_2718(r, out)
+            });
+            assert_eq!(header.receipts_root(), &root, "Receipts root mismatch");
+
+            receipts
+                .into_iter()
+                .flat_map(|wrapper| match wrapper.into_inner() {
+                    ReceiptEnvelope::Legacy(t) => t.receipt.logs,
+                    ReceiptEnvelope::Eip2930(t) => t.receipt.logs,
+                    ReceiptEnvelope::Eip1559(t) => t.receipt.logs,
+                    ReceiptEnvelope::Eip4844(t) => t.receipt.logs,
+                    ReceiptEnvelope::Eip7702(t) => t.receipt.logs,
+                })
+                .collect()
+        });
+
         let db = StateDb::new(
             self.state_trie,
             self.storage_tries,
             self.contracts,
             block_hashes,
+            logs,
         );
         let commit = Commitment::new(
             CommitmentVersion::Block as u16,
@@ -91,19 +120,19 @@ impl<H: EvmBlockHeader> BlockInput<H> {
 
 #[cfg(feature = "host")]
 pub mod host {
-    use std::fmt::Display;
-
     use super::BlockInput;
     use crate::{
         host::db::{AlloyDb, ProofDb, ProviderDb},
+        serde::Eip2718Wrapper,
         EvmBlockHeader,
     };
     use alloy::{network::Network, providers::Provider, transports::Transport};
     use alloy_primitives::Sealed;
     use anyhow::{anyhow, ensure};
     use log::debug;
+    use std::fmt::Display;
 
-    impl<H: EvmBlockHeader> BlockInput<H> {
+    impl<H> BlockInput<H> {
         /// Creates the `BlockInput` containing the necessary EVM state that can be verified against
         /// the block hash.
         pub(crate) async fn from_proof_db<T, N, P>(
@@ -137,6 +166,11 @@ pub mod host {
                 ancestors.push(header);
             }
 
+            let receipts = db.receipt_proof().await?;
+            // wrap the receipts so that they can be serialized
+            let receipts =
+                receipts.map(|receipts| receipts.into_iter().map(Eip2718Wrapper::new).collect());
+
             debug!("state size: {}", state_trie.size());
             debug!("storage tries: {}", storage_tries.len());
             debug!(
@@ -145,13 +179,15 @@ pub mod host {
             );
             debug!("contracts: {}", contracts.len());
             debug!("ancestor blocks: {}", ancestors.len());
+            debug!("receipts: {:?}", receipts.as_ref().map(Vec::len));
 
             let input = BlockInput {
                 header: header.into_inner(),
                 state_trie,
                 storage_tries,
                 contracts,
                 ancestors,
+                receipts,
             };
 
             Ok(input)

crates/steel/src/contract.rs

@@ -284,7 +284,7 @@ where
     /// required.
     pub fn try_call(self) -> Result<S::Return, String> {
         let mut evm = new_evm::<_, H>(
-            WrapStateDb::new(self.env.db()),
+            WrapStateDb::new(self.env.db(), &self.env.header),
             self.env.cfg_env.clone(),
             self.env.header.inner(),
         );

crates/steel/src/ethereum.rs

@@ -79,6 +79,16 @@ impl EvmBlockHeader for EthBlockHeader {
     fn state_root(&self) -> &B256 {
         &self.inner().state_root
     }
+    #[cfg(feature = "unstable-event")]
+    #[inline]
+    fn receipts_root(&self) -> &B256 {
+        &self.inner().receipts_root
+    }
+    #[cfg(feature = "unstable-event")]
+    #[inline]
+    fn logs_bloom(&self) -> &alloy_primitives::Bloom {
+        &self.inner().logs_bloom
+    }
 
     #[inline]
     fn fill_block_env(&self, blk_env: &mut BlockEnv) {

crates/steel/src/event.rs

@@ -0,0 +1,192 @@
+// Copyright 2025 RISC Zero, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Types related to event queries.
+pub use alloy_rpc_types::{Topic, ValueOrArray};
+
+use crate::{state::WrapStateDb, EvmBlockHeader, EvmDatabase, GuestEvmEnv};
+use alloy_primitives::{Address, Log, Sealed};
+use alloy_rpc_types::Filter;
+use alloy_sol_types::SolEvent;
+use std::marker::PhantomData;
+
+/// Represents an EVM event query.
+///
+/// ### Usage
+/// - **Preflight calls on the Host:** To prepare the event query on the host environment and build
+///   the necessary proof, use [Event::preflight].
+/// - **Calls in the Guest:** To initialize the event query in the guest, use [Event::new].
+///
+/// ### Examples
+/// ```rust,no_run
+/// # use risc0_steel::{ethereum::EthEvmEnv, Event};
+/// # use alloy_primitives::address;
+/// # use alloy_sol_types::sol;
+///
+/// # #[tokio::main(flavor = "current_thread")]
+/// # async fn main() -> anyhow::Result<()> {
+/// let contract_address = address!("dAC17F958D2ee523a2206206994597C13D831ec7");
+/// sol! {
+///     interface IERC20 {
+///         event Transfer(address indexed from, address indexed to, uint256 value);
+///     }
+/// }
+///
+/// // Host:
+/// let url = "https://ethereum-rpc.publicnode.com".parse()?;
+/// let mut env = EthEvmEnv::builder().rpc(url).build().await?;
+/// let event = Event::preflight::<IERC20::Transfer>(&mut env).address(contract_address);
+/// event.query().await?;
+///
+/// let evm_input = env.into_input().await?;
+///
+/// // Guest:
+/// let env = evm_input.into_env();
+/// let event = Event::new::<IERC20::Transfer>(&env).address(contract_address);
+/// let logs = event.query();
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+/// [Contract]: crate::Contract
+pub struct Event<S, E> {
+    filter: Filter,
+    env: E,
+    phantom: PhantomData<S>,
+}
+
+impl<H: EvmBlockHeader> Event<(), &GuestEvmEnv<H>> {
+    /// Constructor for executing an event query for a specific Solidity event.
+    pub fn new<S: SolEvent>(env: &GuestEvmEnv<H>) -> Event<S, &GuestEvmEnv<H>> {
+        Event {
+            filter: event_filter::<S, H>(env.header()),
+            env,
+            phantom: PhantomData,
+        }
+    }
+}
+
+#[cfg(feature = "unstable-event")]
+impl<S: SolEvent, H: EvmBlockHeader> Event<S, &GuestEvmEnv<H>> {
+    /// Executes the query and returns the matching logs and panics on failure.
+    ///
+    /// A convenience wrapper for [Event::try_query], panicking if the call fails. Useful when
+    /// success is expected.
+    pub fn query(self) -> Vec<Log<S>> {
+        self.try_query().unwrap()
+    }
+
+    /// Attempts to execute the query and returns the matching logs or an error.
+    pub fn try_query(self) -> anyhow::Result<Vec<Log<S>>> {
+        let logs = WrapStateDb::new(self.env.db(), &self.env.header).logs(self.filter)?;
+        logs.iter()
+            .map(|log| Ok(S::decode_log(log, false)?))
+            .collect()
+    }
+}
+
+impl<S, E> Event<S, E> {
+    /// Sets the address to query with this filter.
+    ///
+    /// See [`Filter::address`].
+    pub fn address<A: Into<ValueOrArray<Address>>>(mut self, address: A) -> Self {
+        self.filter.address = address.into().into();
+        self
+    }
+
+    /// Sets the 1st indexed topic.
+    pub fn topic1<TO: Into<Topic>>(mut self, topic: TO) -> Self {
+        self.filter.topics[1] = topic.into();
+        self
+    }
+
+    /// Sets the 2nd indexed topic.
+    pub fn topic2<TO: Into<Topic>>(mut self, topic: TO) -> Self {
+        self.filter.topics[2] = topic.into();
+        self
+    }
+
+    /// Sets the 3rd indexed topic.
+    pub fn topic3<TO: Into<Topic>>(mut self, topic: TO) -> Self {
+        self.filter.topics[3] = topic.into();
+        self
+    }
+}
+
+#[cfg(feature = "host")]
+mod host {
+    use super::*;
+    use crate::host::HostEvmEnv;
+    use anyhow::{Context, Result};
+    use revm::Database as RevmDatabase;
+    use std::error::Error as StdError;
+
+    impl<D, H: EvmBlockHeader, C> Event<(), &mut HostEvmEnv<D, H, C>>
+    where
+        D: EvmDatabase + Send + 'static,
+        <D as RevmDatabase>::Error: StdError + Send + Sync + 'static,
+    {
+        /// Constructor for preflighting an event query for a specific EVM event.
+        ///
+        /// Initializes the environment for event queries, fetching necessary data via the
+        /// [Provider], and generating a storage proof for any accessed elements using
+        /// [EvmEnv::into_input].
+        ///
+        /// [EvmEnv::into_input]: crate::EvmEnv::into_input
+        /// [EvmEnv]: crate::EvmEnv
+        /// [Provider]: alloy::providers::Provider
+        pub fn preflight<S: SolEvent>(
+            env: &mut HostEvmEnv<D, H, C>,
+        ) -> Event<S, &mut HostEvmEnv<D, H, C>> {
+            Event {
+                filter: event_filter::<S, H>(env.header()),
+                env,
+                phantom: PhantomData,
+            }
+        }
+    }
+
+    impl<S: SolEvent, D, H: EvmBlockHeader, C> Event<S, &mut HostEvmEnv<D, H, C>>
+    where
+        D: EvmDatabase + Send + 'static,
+        <D as RevmDatabase>::Error: StdError + Send + Sync + 'static,
+    {
+        /// Executes the event query using an [EvmEnv] constructed with [Event::preflight].
+        ///
+        /// This uses [tokio::task::spawn_blocking] to run the blocking revm execution.
+        ///
+        /// [EvmEnv]: crate::EvmEnv
+        pub async fn query(self) -> Result<Vec<Log<S>>> {
+            log::info!("Executing preflight querying event '{}'", S::SIGNATURE);
+
+            let logs = self
+                .env
+                .spawn_with_db(move |db| db.logs(self.filter))
+                .await
+                .with_context(|| format!("querying logs for '{}' failed", S::SIGNATURE))?;
+            logs.iter()
+                .map(|log| Ok(S::decode_log(log, false)?))
+                .collect()
+        }
+    }
+}
+
+/// Creates an event filter for a specific event and block header.
+fn event_filter<S: SolEvent, H: EvmBlockHeader>(header: &Sealed<H>) -> Filter {
+    assert!(!S::ANONYMOUS, "Anonymous events not supported");
+    Filter::new()
+        .event_signature(S::SIGNATURE_HASH)
+        .at_block_hash(header.seal())
+}