Merge pull request #720 from worldcoin/0xkitsune/simulate-tx

feat(simulate-tx): simulate transactions before broadcasting

src/contracts/mod.rs

@@ -277,7 +277,7 @@ impl IdentityManager {
     ) -> anyhow::Result<TransactionId> {
         let proof_points_array: [U256; 8] = deletion_proof.into();
 
-        let register_identities_transaction = self
+        let delete_identities_transaction = self
             .abi
             .delete_identities(
                 proof_points_array,
@@ -288,7 +288,7 @@ impl IdentityManager {
             .tx;
 
         self.ethereum
-            .send_transaction(register_identities_transaction, true)
+            .send_transaction(delete_identities_transaction, true)
             .await
             .map_err(|tx_err| anyhow!("{}", tx_err.to_string()))
     }

src/ethereum/mod.rs

@@ -1,6 +1,7 @@
 use std::collections::HashMap;
 use std::sync::Arc;
 
+use ethers::providers::Middleware;
 use ethers::types::transaction::eip2718::TypedTransaction;
 use ethers::types::Address;
 pub use read::ReadProvider;
@@ -71,6 +72,11 @@ impl Ethereum {
         tx: TypedTransaction,
         only_once: bool,
     ) -> Result<TransactionId, TxError> {
+        if let Err(err) = self.read_provider.call(&tx, None).await {
+            tracing::error!("Error simulating transaction: {:?}", err);
+            return Err(TxError::Simulate(anyhow::Error::new(err)));
+        }
+
         self.write_provider.send_transaction(tx, only_once).await
     }
 

src/ethereum/write/mod.rs

@@ -35,6 +35,9 @@ pub enum TxError {
     #[error("Error sending transaction: {0}")]
     Send(anyhow::Error),
 
+    #[error("Error simulating transaction: {0}")]
+    Simulate(anyhow::Error),
+
     #[error("Timeout while waiting for confirmations")]
     ConfirmationTimeout,