From e8ec0a7d8ec866ea10e30dafe2dacf90d1561226 Mon Sep 17 00:00:00 2001
From: Ammar Arif <evergreenkary@gmail.com>
Date: Wed, 16 Oct 2024 16:38:21 -0400
Subject: [PATCH] fix: include message from address in the tx calldata

---
 crates/katana/rpc/rpc-types/src/message.rs |  7 ++++-
 crates/katana/rpc/rpc/tests/messaging.rs   | 36 ++++++++++++++++++++--
 2 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/crates/katana/rpc/rpc-types/src/message.rs b/crates/katana/rpc/rpc-types/src/message.rs
index 5bb95ffa83..77f49e0551 100644
--- a/crates/katana/rpc/rpc-types/src/message.rs
+++ b/crates/katana/rpc/rpc-types/src/message.rs
@@ -27,13 +27,18 @@ impl MsgFromL1 {
             &self.0.payload,
         );
 
+        // In an l1_handler transaction, the first element of the calldata is always the Ethereum
+        // address of the sender (msg.sender). https://docs.starknet.io/documentation/architecture_and_concepts/Network_Architecture/messaging-mechanism/#l1-l2-messages
+        let mut calldata = vec![Felt::from(self.0.from_address)];
+        calldata.extend(self.0.payload);
+
         L1HandlerTx {
             nonce,
             chain_id,
+            calldata,
             message_hash,
             paid_fee_on_l1,
             version: Felt::ZERO,
-            calldata: self.0.payload,
             contract_address: self.0.to_address.into(),
             entry_point_selector: self.0.entry_point_selector,
         }
diff --git a/crates/katana/rpc/rpc/tests/messaging.rs b/crates/katana/rpc/rpc/tests/messaging.rs
index fecc5155c6..ac11f7e8a3 100644
--- a/crates/katana/rpc/rpc/tests/messaging.rs
+++ b/crates/katana/rpc/rpc/tests/messaging.rs
@@ -330,10 +330,42 @@ async fn estimate_message_fee() -> Result<()> {
     // Compute the contract address of the l1 handler contract
     let l1handler_address = get_contract_address(Felt::ZERO, class_hash, &[], Felt::ZERO);
 
-    // Attempt to estimate the cost of calling a #[l1handler] function
+    // This is the function signature of the #[l1handler] function we''re gonna call. Though the
+    // function accepts two arguments, we're only gonna pass one argument, as the `from_address`
+    // of the `MsgFromL1` will be automatically injected as part of the function calldata.
+    //
+    // See https://docs.starknet.io/documentation/architecture_and_concepts/Network_Architecture/messaging-mechanism/#l1-l2-messages.
+    //
+    // #[l1_handler]
+    // fn msg_handler_value(ref self: ContractState, from_address: felt252, value: felt252)
 
     let entry_point_selector = selector!("msg_handler_value");
-    let payload = vec![felt!("0x123"), felt!("123")]; // function arguments
+    let payload = vec![felt!("123")];
+    let from_address = felt!("0x1337");
+    let to_address = l1handler_address;
+
+    let msg = MsgFromL1 {
+        payload,
+        to_address,
+        entry_point_selector,
+        from_address: from_address.try_into()?,
+    };
+
+    let result = provider.estimate_message_fee(msg, BlockId::Tag(BlockTag::Pending)).await;
+    assert!(result.is_ok());
+
+    // #[derive(Drop, Serde)]
+    // struct MyData {
+    //     a: felt252,
+    //     b: felt252,
+    // }
+    //
+    // #[l1_handler]
+    // fn msg_handler_struct(ref self: ContractState, from_address: felt252, data: MyData)
+
+    let entry_point_selector = selector!("msg_handler_struct");
+    // [ MyData.a , MyData.b ]
+    let payload = vec![felt!("1"), felt!("2")];
     let from_address = felt!("0x1337");
     let to_address = l1handler_address;