EVM: DST20 v2 burn of sent amount (#2911)

* Correctly burn amount on original contract * Add tests for burn event
DeFiCh · May 7, 2024 · 6ec7477 · 6ec7477
1 parent 3d6663d
commit 6ec7477
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Showing 3 changed files with 16 additions and 59 deletions.
diff --git a/lib/ain-contracts/dst20_v2/DST20V2.sol b/lib/ain-contracts/dst20_v2/DST20V2.sol
@@ -588,6 +588,7 @@ contract ERC20 is Context, IERC20, IERC20Metadata, IDST20Upgradeable {
 
         // Upgrade available
         if (newAmount != amount) {
+            _burn(msg.sender, amount);
             IERC20(newTokenContractAddress).transfer(msg.sender, newAmount);
         }
 

diff --git a/lib/ain-evm/src/precompiles/token_split.rs b/lib/ain-evm/src/precompiles/token_split.rs
@@ -121,28 +121,9 @@ impl DVMStatePrecompile for TokenSplit {
             reset_storage: false,
         };
 
-        let Ok(storage) =
-            get_original_contract_storage_update(handle, sender, original_contract, input_amount)
-        else {
-            return Err(PrecompileFailure::Error {
-                exit_status: ExitError::Other("Error getting storage update".into()),
-            });
-        };
-
-        let original_contract_state_changes = Apply::Modify {
-            address: original_contract,
-            basic: handle.basic(original_contract),
-            code: None,
-            storage,
-            reset_storage: false,
-        };
-
         Ok(PrecompileOutput {
             exit_status: ExitSucceed::Returned,
-            state_changes: Some(vec![
-                original_contract_state_changes,
-                new_contract_state_changes,
-            ]),
+            state_changes: Some(vec![new_contract_state_changes]),
             output,
         })
     }
@@ -196,41 +177,3 @@ fn get_new_contract_storage_update(
         (total_supply_index, u256_to_h256(new_total_supply)),
     ]))
 }
-
-fn get_original_contract_storage_update(
-    handle: &mut impl PrecompileHandle,
-    sender: H160,
-    contract: H160,
-    amount: U256,
-) -> Result<BTreeMap<H256, H256>> {
-    let contract_balance_storage_index = get_address_storage_index(H256::zero(), sender);
-    let sender_balance = U256::from(
-        handle
-            .storage(contract, contract_balance_storage_index)
-            .as_bytes(),
-    );
-
-    debug!("sender_balance : {}", sender_balance);
-
-    let new_sender_balance = sender_balance
-        .checked_sub(amount)
-        .ok_or_else(|| format_err!("Total supply overflow/underflow"))?;
-    debug!("new_sender_balance : {:x}", new_sender_balance);
-
-    let total_supply_index = H256::from_low_u64_be(2);
-    let total_supply = U256::from(handle.storage(contract, total_supply_index).as_bytes());
-
-    let new_total_supply = total_supply
-        .checked_sub(amount)
-        .ok_or_else(|| format_err!("Total supply overflow/underflow"))?;
-
-    debug!("new_total_supply : {:x}", new_total_supply);
-
-    Ok(BTreeMap::from([
-        (
-            contract_balance_storage_index,
-            u256_to_h256(new_sender_balance),
-        ),
-        (total_supply_index, u256_to_h256(new_total_supply)),
-    ]))
-}
diff --git a/test/functional/feature_evm_token_split.py b/test/functional/feature_evm_token_split.py
@@ -142,6 +142,10 @@ def setup_variables(self):
         self.evm_address = self.nodes[0].getnewaddress("", "erc55")
         self.evm_privkey = self.nodes[0].dumpprivkey(self.evm_address)
 
+        self.burn_address = self.nodes[0].w3.to_checksum_address(
+            "0x0000000000000000000000000000000000000000"
+        )
+
         self.contract_address_metav1 = self.nodes[0].w3.to_checksum_address(
             "0xff00000000000000000000000000000000000001"
         )
@@ -769,10 +773,19 @@ def execute_split_transaction(
             address=destination_contract, abi=self.dst20_v2_abi
         )
 
-        # Check transfer token logs on new contract
+        # Check transfer from sender to burn address
         events = meta_contract_new.events.Transfer().process_log(
             list(tx_receipt["logs"])[1]
         )
+
+        assert_equal(events["event"], "Transfer")
+        assert_equal(events["args"]["to"], self.burn_address)
+        assert_equal(events["args"]["value"], amount_to_send)
+
+        # Check transfer token logs on new contract
+        events = meta_contract_new.events.Transfer().process_log(
+            list(tx_receipt["logs"])[2]
+        )
         assert_equal(events["event"], "Transfer")
         assert_equal(events["args"]["to"], self.evm_address)
         assert_equal(events["args"]["value"], amount_to_receive)