feat: make l1tol2 message consumption take leafIndex

noir-projects/aztec-nr/aztec/src/context/avm_context.nr

@@ -1,3 +1,4 @@
+use crate::hash::{compute_secret_hash, compute_message_hash, compute_message_nullifier};
 use dep::protocol_types::{
     address::{AztecAddress, EthAddress},
     constants::{L1_TO_L2_MESSAGE_LENGTH, NESTED_CALL_L2_GAS_BUFFER}, header::Header
@@ -128,8 +129,21 @@ impl PublicContextInterface for AvmContext {
         self.accumulate_unencrypted_logs(event_selector, log);
     }
 
-    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress) {
-        assert(false, "'consume_l1_to_l2_message' not implemented!");
+    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress, leaf_index: Field) {
+        let secret_hash = compute_secret_hash(secret);
+        let message_hash = compute_message_hash(
+            sender,
+            self.chain_id(),
+            /*recipient=*/self.this_address(),
+            self.version(),
+            content,
+            secret_hash
+        );
+
+        assert(self.l1_to_l2_msg_exists(message_hash, leaf_index), "Tried to consume inexistent L1-to-L2 message");
+        let nullifier = compute_message_nullifier(message_hash, secret, leaf_index);
+        // Push nullifier (and the "commitment" corresponding to this can be "empty")
+        self.push_new_nullifier(nullifier, 0);
     }
 
     fn message_portal(&mut self, recipient: EthAddress, content: Field) {

noir-projects/aztec-nr/aztec/src/context/interface.nr

@@ -27,7 +27,7 @@ trait PublicContextInterface {
     fn fee_per_l1_gas(self) -> Field;
     fn fee_per_l2_gas(self) -> Field;
     fn message_portal(&mut self, recipient: EthAddress, content: Field);
-    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress);
+    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress, leaf_index: Field);
     fn accumulate_encrypted_logs<N>(&mut self, log: [Field; N]);
     fn accumulate_unencrypted_logs<T>(&mut self, log: T);
     fn call_public_function<ARGS_COUNT, RETURNS_COUNT>(

noir-projects/aztec-nr/aztec/src/context/public_context.nr

@@ -263,7 +263,8 @@ impl PublicContextInterface for PublicContext {
 
     // We can consume message with a secret in public context because the message cannot be modified and therefore
     // there is no front-running risk (e.g. somebody could front run you to claim your tokens to your address).
-    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress) {
+    // Leaf index is not used in public context, but it is used in the AVMContext which will replace it.
+    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress, _leaf_index: Field) {
         let this = (*self).this_address();
         let nullifier = process_l1_to_l2_message(
             self.historical_header.state.l1_to_l2_message_tree.root,

noir-projects/noir-contracts/contracts/gas_token_contract/src/main.nr

@@ -12,11 +12,11 @@ contract GasToken {
     }
 
     #[aztec(public)]
-    fn claim_public(to: AztecAddress, amount: Field, secret: Field) {
+    fn claim_public(to: AztecAddress, amount: Field, secret: Field, leaf_index: Field) {
         let content_hash = get_bridge_gas_msg_hash(to, amount);
 
         // Consume message and emit nullifier
-        context.consume_l1_to_l2_message(content_hash, secret, context.this_portal_address());
+        context.consume_l1_to_l2_message(content_hash, secret, context.this_portal_address(), leaf_index);
 
         let new_balance = storage.balances.at(to).read() + U128::from_integer(amount);
         storage.balances.at(to).write(new_balance);