From 43142e86a8aeb4fcd1f86137b0b30f3db11bc62c Mon Sep 17 00:00:00 2001
From: 0xKitsune <0xKitsune@protonmail.com>
Date: Wed, 1 May 2024 17:42:27 -0700
Subject: [PATCH 1/2] simulate tx

---
 src/contracts/mod.rs      | 12 ++++++++++--
 src/ethereum/mod.rs       | 10 ++++++++++
 src/ethereum/write/mod.rs |  3 +++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/contracts/mod.rs b/src/contracts/mod.rs
index f4e64832..cf41e027 100644
--- a/src/contracts/mod.rs
+++ b/src/contracts/mod.rs
@@ -260,6 +260,10 @@ impl IdentityManager {
             )
             .tx;
 
+        self.ethereum
+            .simulate_transaction(&register_identities_transaction)
+            .await?;
+
         self.ethereum
             .send_transaction(register_identities_transaction, true)
             .await
@@ -277,7 +281,7 @@ 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 +292,11 @@ impl IdentityManager {
             .tx;
 
         self.ethereum
-            .send_transaction(register_identities_transaction, true)
+            .simulate_transaction(&delete_identities_transaction)
+            .await?;
+
+        self.ethereum
+            .send_transaction(delete_identities_transaction, true)
             .await
             .map_err(|tx_err| anyhow!("{}", tx_err.to_string()))
     }
diff --git a/src/ethereum/mod.rs b/src/ethereum/mod.rs
index 65aaee3b..0c408096 100644
--- a/src/ethereum/mod.rs
+++ b/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;
@@ -74,6 +75,15 @@ impl Ethereum {
         self.write_provider.send_transaction(tx, only_once).await
     }
 
+    pub async fn simulate_transaction(&self, tx: &TypedTransaction) -> Result<(), 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)));
+        }
+
+        Ok(())
+    }
+
     pub async fn fetch_pending_transactions(&self) -> Result<Vec<TransactionId>, TxError> {
         self.write_provider.fetch_pending_transactions().await
     }
diff --git a/src/ethereum/write/mod.rs b/src/ethereum/write/mod.rs
index 7aeec2a7..42d2c476 100644
--- a/src/ethereum/write/mod.rs
+++ b/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,
 

From c1e660ef9e0d5675f98ed599c9af446782ffe3e1 Mon Sep 17 00:00:00 2001
From: 0xKitsune <0xKitsune@protonmail.com>
Date: Wed, 1 May 2024 17:44:41 -0700
Subject: [PATCH 2/2] simulate before broadcasting

---
 src/contracts/mod.rs | 8 --------
 src/ethereum/mod.rs  | 6 +-----
 2 files changed, 1 insertion(+), 13 deletions(-)

diff --git a/src/contracts/mod.rs b/src/contracts/mod.rs
index cf41e027..5a7ad913 100644
--- a/src/contracts/mod.rs
+++ b/src/contracts/mod.rs
@@ -260,10 +260,6 @@ impl IdentityManager {
             )
             .tx;
 
-        self.ethereum
-            .simulate_transaction(&register_identities_transaction)
-            .await?;
-
         self.ethereum
             .send_transaction(register_identities_transaction, true)
             .await
@@ -291,10 +287,6 @@ impl IdentityManager {
             )
             .tx;
 
-        self.ethereum
-            .simulate_transaction(&delete_identities_transaction)
-            .await?;
-
         self.ethereum
             .send_transaction(delete_identities_transaction, true)
             .await
diff --git a/src/ethereum/mod.rs b/src/ethereum/mod.rs
index 0c408096..142a948b 100644
--- a/src/ethereum/mod.rs
+++ b/src/ethereum/mod.rs
@@ -72,16 +72,12 @@ impl Ethereum {
         tx: TypedTransaction,
         only_once: bool,
     ) -> Result<TransactionId, TxError> {
-        self.write_provider.send_transaction(tx, only_once).await
-    }
-
-    pub async fn simulate_transaction(&self, tx: &TypedTransaction) -> Result<(), 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)));
         }
 
-        Ok(())
+        self.write_provider.send_transaction(tx, only_once).await
     }
 
     pub async fn fetch_pending_transactions(&self) -> Result<Vec<TransactionId>, TxError> {