WIP: Implement prestateTracer (#3923)

Co-authored-by: Matthias Seitz <matthias.seitz@outlook.de>

crates/rpc/rpc-types/src/eth/trace/geth/pre_state.rs

@@ -1,4 +1,4 @@
-use reth_primitives::{serde_helper::num::from_int_or_hex_opt, Address, H256, U256};
+use reth_primitives::{serde_helper::num::from_int_or_hex_opt, Address, Bytes, H256, U256};
 use serde::{Deserialize, Serialize};
 use std::collections::BTreeMap;
 
@@ -29,7 +29,7 @@ pub struct AccountState {
     )]
     pub balance: Option<U256>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub code: Option<String>,
+    pub code: Option<Bytes>,
     #[serde(
         default,
         deserialize_with = "from_int_or_hex_opt",
@@ -47,6 +47,12 @@ pub struct PreStateConfig {
     pub diff_mode: Option<bool>,
 }
 
+impl PreStateConfig {
+    pub fn is_diff_mode(&self) -> bool {
+        self.diff_mode.unwrap_or_default()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -86,4 +92,11 @@ mod tests {
             _ => unreachable!(),
         }
     }
+
+    #[test]
+    fn test_is_diff_mode() {
+        assert!(PreStateConfig { diff_mode: Some(true) }.is_diff_mode());
+        assert!(!PreStateConfig { diff_mode: Some(false) }.is_diff_mode());
+        assert!(!PreStateConfig { diff_mode: None }.is_diff_mode());
+    }
 }

crates/rpc/rpc/src/debug.rs

@@ -2,7 +2,8 @@ use crate::{
     eth::{
         error::{EthApiError, EthResult},
         revm_utils::{
-            clone_into_empty_db, inspect, replay_transactions_until, result_output, EvmOverrides,
+            clone_into_empty_db, inspect, inspect_and_return_db, replay_transactions_until,
+            result_output, EvmOverrides,
         },
         EthTransactions, TransactionSource,
     },
@@ -255,7 +256,26 @@ where
                         return Ok(frame)
                     }
                     GethDebugBuiltInTracerType::PreStateTracer => {
-                        Err(EthApiError::Unsupported("pre state tracer currently unsupported."))
+                        let prestate_config = tracer_config
+                            .into_pre_state_config()
+                            .map_err(|_| EthApiError::InvalidTracerConfig)?;
+                        let mut inspector = TracingInspector::new(
+                            TracingInspectorConfig::from_geth_config(&config),
+                        );
+
+                        let frame =
+                            self.inner
+                                .eth_api
+                                .spawn_with_call_at(call, at, overrides, move |db, env| {
+                                    let (res, _, db) =
+                                        inspect_and_return_db(db, env, &mut inspector)?;
+                                    let frame = inspector
+                                        .into_geth_builder()
+                                        .geth_prestate_traces(&res, prestate_config, &db)?;
+                                    Ok(frame)
+                                })
+                                .await?;
+                        return Ok(frame.into())
                     }
                     GethDebugBuiltInTracerType::NoopTracer => Ok(NoopFrame::default().into()),
                 },
@@ -354,7 +374,22 @@ where
                         return Ok((frame.into(), res.state))
                     }
                     GethDebugBuiltInTracerType::PreStateTracer => {
-                        Err(EthApiError::Unsupported("prestate tracer is unimplemented yet."))
+                        let prestate_config = tracer_config
+                            .into_pre_state_config()
+                            .map_err(|_| EthApiError::InvalidTracerConfig)?;
+
+                        let mut inspector = TracingInspector::new(
+                            TracingInspectorConfig::from_geth_config(&config),
+                        );
+                        let (res, _) = inspect(&mut *db, env, &mut inspector)?;
+
+                        let frame = inspector.into_geth_builder().geth_prestate_traces(
+                            &res,
+                            prestate_config,
+                            &*db,
+                        )?;
+
+                        return Ok((frame.into(), res.state))
                     }
                     GethDebugBuiltInTracerType::NoopTracer => {
                         Ok((NoopFrame::default().into(), Default::default()))