Fix selfdestruct for EIP-6780 with non-empty balances (#493)

* Fix selfdestruct for EIP-6780 with non-empty balances

* Add test case

* Misc

* Review

trace_decoder/src/decoding.rs

@@ -357,6 +357,23 @@ fn apply_deltas_to_trie_state(
         trie_state.state.insert_by_key(val_k, account)?;
     }
 
+    // Remove any accounts that self-destructed.
+    for hashed_acc_addr in deltas.self_destructed_accounts.iter() {
+        let val_k = TrieKey::from_hash(*hashed_acc_addr);
+
+        trie_state.storage.remove(hashed_acc_addr);
+
+        if let Some(remaining_account_key) =
+            delete_node_and_report_remaining_key_if_branch_collapsed(
+                trie_state.state.as_mut_hashed_partial_trie_unchecked(),
+                &val_k,
+            )?
+        {
+            out.additional_state_trie_paths_to_not_hash
+                .push(remaining_account_key);
+        }
+    }
+
     Ok(out)
 }
 

trace_decoder/src/lib.rs

@@ -240,6 +240,10 @@ pub struct TxnTrace {
     /// Contract code that this account has accessed or created
     #[serde(skip_serializing_if = "Option::is_none")]
     pub code_usage: Option<ContractCodeUsage>,
+
+    /// True if the account got self-destructed at the end of this txn.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub self_destructed: Option<bool>,
 }
 
 /// Contract code access type. Used by txn traces.

trace_decoder/src/processed_block_trace.rs

@@ -150,6 +150,10 @@ impl TxnInfo {
                     }
                 }
             }
+
+            if trace.self_destructed.unwrap_or_default() {
+                nodes_used_by_txn.self_destructed_accounts.push(hashed_addr);
+            }
         }
 
         for &hashed_addr in extra_state_accesses {
@@ -223,6 +227,7 @@ pub(crate) struct NodesUsedByTxn {
     #[allow(clippy::type_complexity)]
     pub storage_writes: Vec<(H256, Vec<(TrieKey, Vec<u8>)>)>,
     pub state_accounts_with_no_accesses_but_storage_tries: HashMap<H256, H256>,
+    pub self_destructed_accounts: Vec<H256>,
 }
 
 #[derive(Debug)]

trace_decoder/src/typed_mpt.rs

@@ -76,6 +76,9 @@ impl<T> TypedMpt<T> {
     fn as_hashed_partial_trie(&self) -> &HashedPartialTrie {
         &self.inner
     }
+    fn as_mut_hashed_partial_trie_unchecked(&mut self) -> &mut HashedPartialTrie {
+        &mut self.inner
+    }
     fn root(&self) -> H256 {
         self.inner.hash()
     }
@@ -272,6 +275,9 @@ impl StateTrie {
     pub fn as_hashed_partial_trie(&self) -> &mpt_trie::partial_trie::HashedPartialTrie {
         self.typed.as_hashed_partial_trie()
     }
+    pub fn as_mut_hashed_partial_trie_unchecked(&mut self) -> &mut HashedPartialTrie {
+        self.typed.as_mut_hashed_partial_trie_unchecked()
+    }
     pub fn remove(&mut self, key: TrieKey) -> Result<Option<AccountRlp>, Error> {
         self.typed.remove(key)
     }
@@ -328,7 +334,7 @@ impl StorageTrie {
     pub fn root(&self) -> H256 {
         self.untyped.hash()
     }
-    pub fn as_hashed_partial_trie(&self) -> &mpt_trie::partial_trie::HashedPartialTrie {
+    pub fn as_hashed_partial_trie(&self) -> &HashedPartialTrie {
         &self.untyped
     }
 

zero_bin/rpc/src/native/txn.rs

@@ -175,13 +175,15 @@ async fn process_tx_traces(
         );
         let code = process_code(post_state, read_state, &mut code_db).await;
         let nonce = process_nonce(post_state, &code);
+        let self_destructed = process_self_destruct(post_state, pre_state);
 
         let result = TxnTrace {
             balance,
             nonce,
             storage_read,
             storage_written,
             code_usage: code,
+            self_destructed,
         };
 
         traces.insert(address, result);
@@ -208,6 +210,30 @@ fn process_nonce(
         })
 }
 
+/// Processes the self destruct for the given account state.
+/// This wraps the actual boolean indicator into an `Option` so that we can skip
+/// serialization of `None` values, which represent most cases.
+fn process_self_destruct(
+    post_state: Option<&AccountState>,
+    pre_state: Option<&AccountState>,
+) -> Option<bool> {
+    if post_state.is_none() {
+        // EIP-6780:
+        // A contract is considered created at the beginning of a create
+        // transaction or when a CREATE series operation begins execution (CREATE,
+        // CREATE2, and other operations that deploy contracts in the future). If a
+        // balance exists at the contract’s new address it is still considered to be a
+        // contract creation.
+        if let Some(acc) = pre_state {
+            if acc.code.is_none() && acc.storage.keys().collect::<Vec<_>>().is_empty() {
+                return Some(true);
+            }
+        }
+    }
+
+    None
+}
+
 /// Processes the storage for the given account state.
 ///
 /// Returns the storage read and written for the given account in the