Always create system address after block execution (#21)

* state root mismatch fix

* fsyntax

* comments

src/gnosis.rs

@@ -15,6 +15,7 @@ use reth::{
 use reth_chainspec::ChainSpec;
 use reth_errors::BlockValidationError;
 use reth_evm::{execute::BlockExecutionError, ConfigureEvm};
+use revm_primitives::{Account, AccountInfo, AccountStatus};
 
 pub const SYSTEM_ADDRESS: Address = address!("fffffffffffffffffffffffffffffffffffffffe");
 
@@ -184,8 +185,30 @@ where
         })
     })?;
 
-    // Clean-up post system tx context
-    state.remove(&SYSTEM_ADDRESS);
+    // in gnosis aura, system account needs to be included in the state and not removed (despite EIP-158/161, even if empty)
+    // here we have a generalized check if system account is in state, or needs to be created
+
+    // keeping this generalized, instead of only in block 1
+    // (AccountStatus::Touched | AccountStatus::LoadedAsNotExisting) means the account is not in the state
+    let should_create = state.get(&SYSTEM_ADDRESS).map_or(true, |system_account| {
+        // true if account not in state (either None, or Touched | LoadedAsNotExisting)
+        system_account.status == (AccountStatus::Touched | AccountStatus::LoadedAsNotExisting)
+    });
+
+    // this check needs to be there in every call, so instead of making it into a function which is called from post_execution, we can just include it in the rewards function
+    if should_create {
+        let account = Account {
+            info: AccountInfo::default(),
+            storage: Default::default(),
+            // we force the account to be created by changing the status
+            status: AccountStatus::Touched | AccountStatus::Created,
+        };
+        state.insert(SYSTEM_ADDRESS, account);
+    } else {
+        // clear the system address account from state transitions, else EIP-158/161 (impl in revm) removes it from state
+        state.remove(&SYSTEM_ADDRESS);
+    }
+
     state.remove(&evm.block().coinbase);
     evm.context.evm.db.commit(state);
     // re-set the previous env