do not insert empty account diffs

Author: xqft

crates/l2/common/src/state_diff.rs

@@ -59,7 +59,7 @@ pub enum StateDiffError {
     EVMError(#[from] EvmError),
 }
 
-#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+#[derive(Debug, Clone, Default, Serialize, Deserialize, PartialEq)]
 pub struct AccountStateDiff {
     pub new_balance: Option<U256>,
     pub nonce_diff: u16,

crates/l2/sequencer/block_producer/payload_builder.rs

@@ -327,7 +327,10 @@ fn get_account_diffs_in_tx(
                     bytecode_hash: None,
                 };
 
-                modified_accounts.insert(*address, account_state_diff);
+                // If account state diff is NOT empty
+                if account_state_diff != AccountStateDiff::default() {
+                    modified_accounts.insert(*address, account_state_diff);
+                }
             }
 
             // Then if there is any storage change, we add it to the account state diff