From 074c5c301373cec1a0b755e213abf973293a0014 Mon Sep 17 00:00:00 2001
From: Dan Cline <6798349+Rjected@users.noreply.github.com>
Date: Tue, 30 Apr 2024 22:06:37 -0400
Subject: [PATCH] feat: introduce external context GAT in ConfigureEvm (#7842)

---
 crates/ethereum/evm/src/lib.rs  | 12 +++++++++++-
 crates/evm/src/lib.rs           | 11 +++++++----
 crates/optimism/evm/src/lib.rs  |  6 ++++--
 crates/revm/src/test_utils.rs   | 17 +++++++++++------
 examples/custom-evm/src/main.rs |  4 +++-
 5 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/crates/ethereum/evm/src/lib.rs b/crates/ethereum/evm/src/lib.rs
index a320a2b3c..adcfd700d 100644
--- a/crates/ethereum/evm/src/lib.rs
+++ b/crates/ethereum/evm/src/lib.rs
@@ -14,6 +14,7 @@ use reth_primitives::{
     revm_primitives::{AnalysisKind, CfgEnvWithHandlerCfg, TxEnv},
     Address, ChainSpec, Head, Header, Transaction, U256,
 };
+use reth_revm::{Database, EvmBuilder};
 pub mod execute;
 
 /// Ethereum-related EVM configuration.
@@ -55,7 +56,16 @@ impl ConfigureEvmEnv for EthEvmConfig {
     }
 }
 
-impl ConfigureEvm for EthEvmConfig {}
+impl ConfigureEvm for EthEvmConfig {
+    type DefaultExternalContext<'a> = ();
+
+    fn evm<'a, DB: Database + 'a>(
+        &self,
+        db: DB,
+    ) -> reth_revm::Evm<'a, Self::DefaultExternalContext<'a>, DB> {
+        EvmBuilder::default().with_db(db).build()
+    }
+}
 
 #[cfg(test)]
 mod tests {
diff --git a/crates/evm/src/lib.rs b/crates/evm/src/lib.rs
index 9179abc33..154aac2d7 100644
--- a/crates/evm/src/lib.rs
+++ b/crates/evm/src/lib.rs
@@ -16,14 +16,15 @@ pub mod execute;
 
 /// Trait for configuring the EVM for executing full blocks.
 pub trait ConfigureEvm: ConfigureEvmEnv {
+    /// Associated type for the default external context that should be configured for the EVM.
+    type DefaultExternalContext<'a>;
+
     /// Returns new EVM with the given database
     ///
     /// This does not automatically configure the EVM with [ConfigureEvmEnv] methods. It is up to
     /// the caller to call an appropriate method to fill the transaction and block environment
     /// before executing any transactions using the provided EVM.
-    fn evm<'a, DB: Database + 'a>(&self, db: DB) -> Evm<'a, (), DB> {
-        EvmBuilder::default().with_db(db).build()
-    }
+    fn evm<'a, DB: Database + 'a>(&self, db: DB) -> Evm<'a, Self::DefaultExternalContext<'a>, DB>;
 
     /// Returns a new EVM with the given database configured with the given environment settings,
     /// including the spec id.
@@ -33,7 +34,7 @@ pub trait ConfigureEvm: ConfigureEvmEnv {
         &self,
         db: DB,
         env: EnvWithHandlerCfg,
-    ) -> Evm<'a, (), DB> {
+    ) -> Evm<'a, Self::DefaultExternalContext<'a>, DB> {
         let mut evm = self.evm(db);
         evm.modify_spec_id(env.spec_id());
         evm.context.evm.env = env.env;
@@ -43,6 +44,8 @@ pub trait ConfigureEvm: ConfigureEvmEnv {
     /// Returns a new EVM with the given database configured with the given environment settings,
     /// including the spec id.
     ///
+    /// This will use the given external inspector as the EVM external context.
+    ///
     /// This will preserve any handler modifications
     fn evm_with_env_and_inspector<'a, DB, I>(
         &self,
diff --git a/crates/optimism/evm/src/lib.rs b/crates/optimism/evm/src/lib.rs
index 6a6324302..8ab6fd426 100644
--- a/crates/optimism/evm/src/lib.rs
+++ b/crates/optimism/evm/src/lib.rs
@@ -61,7 +61,9 @@ impl ConfigureEvmEnv for OptimismEvmConfig {
 }
 
 impl ConfigureEvm for OptimismEvmConfig {
-    fn evm<'a, DB: Database + 'a>(&self, db: DB) -> Evm<'a, (), DB> {
+    type DefaultExternalContext<'a> = ();
+
+    fn evm<'a, DB: Database + 'a>(&self, db: DB) -> Evm<'a, Self::DefaultExternalContext<'a>, DB> {
         EvmBuilder::default().with_db(db).optimism().build()
     }
 
@@ -83,7 +85,7 @@ impl ConfigureEvm for OptimismEvmConfig {
 mod tests {
     use super::*;
     use reth_primitives::revm_primitives::{BlockEnv, CfgEnv};
-    use reth_revm::primitives::SpecId;
+    use revm_primitives::SpecId;
 
     #[test]
     #[ignore]
diff --git a/crates/revm/src/test_utils.rs b/crates/revm/src/test_utils.rs
index 193736987..73df4ea4b 100644
--- a/crates/revm/src/test_utils.rs
+++ b/crates/revm/src/test_utils.rs
@@ -18,11 +18,12 @@ use std::collections::HashMap;
 #[cfg(feature = "optimism")]
 use {
     reth_primitives::revm::env::fill_op_tx_env,
-    revm::{
-        inspector_handle_register,
-        primitives::{HandlerCfg, SpecId},
-        Database, Evm, EvmBuilder, GetInspector,
-    },
+    revm::{inspector_handle_register, GetInspector},
+};
+
+use revm::{
+    primitives::{HandlerCfg, SpecId},
+    Database, Evm, EvmBuilder,
 };
 
 /// Mock state for testing
@@ -158,9 +159,13 @@ impl ConfigureEvmEnv for TestEvmConfig {
 }
 
 impl ConfigureEvm for TestEvmConfig {
-    #[cfg(feature = "optimism")]
+    type DefaultExternalContext<'a> = ();
+
     fn evm<'a, DB: Database + 'a>(&self, db: DB) -> Evm<'a, (), DB> {
+        #[cfg(feature = "optimism")]
         let handler_cfg = HandlerCfg { spec_id: SpecId::LATEST, is_optimism: true };
+        #[cfg(not(feature = "optimism"))]
+        let handler_cfg = HandlerCfg { spec_id: SpecId::LATEST };
         EvmBuilder::default().with_db(db).with_handler_cfg(handler_cfg).build()
     }
 
diff --git a/examples/custom-evm/src/main.rs b/examples/custom-evm/src/main.rs
index e5362c808..31edf4f03 100644
--- a/examples/custom-evm/src/main.rs
+++ b/examples/custom-evm/src/main.rs
@@ -81,7 +81,9 @@ impl ConfigureEvmEnv for MyEvmConfig {
 }
 
 impl ConfigureEvm for MyEvmConfig {
-    fn evm<'a, DB: Database + 'a>(&self, db: DB) -> Evm<'a, (), DB> {
+    type DefaultExternalContext<'a> = ();
+
+    fn evm<'a, DB: Database + 'a>(&self, db: DB) -> Evm<'a, Self::DefaultExternalContext<'a>, DB> {
         EvmBuilder::default()
             .with_db(db)
             // add additional precompiles