Merge pull request #4909 from ethereum-optimism/ctb/fix-legacy-withdraw

contracts-bedrock: L2StandardBridge legacy `withdraw`

packages/contracts-bedrock/.gas-snapshot

@@ -167,20 +167,21 @@ L2OutputOracleUpgradeable_Test:test_initValuesOnProxy_succeeds() (gas: 26093)
 L2OutputOracleUpgradeable_Test:test_initializeImpl_alreadyInitialized_reverts() (gas: 15149)
 L2OutputOracleUpgradeable_Test:test_initializeProxy_alreadyInitialized_reverts() (gas: 20131)
 L2OutputOracleUpgradeable_Test:test_upgrading_succeeds() (gas: 180413)
-L2StandardBridge_BridgeERC20To_Test:test_bridgeERC20To_succeeds() (gas: 387796)
-L2StandardBridge_BridgeERC20To_Test:test_withdrawTo_withdrawingERC20_succeeds() (gas: 388044)
+L2StandardBridge_BridgeERC20To_Test:test_bridgeERC20To_succeeds() (gas: 387797)
+L2StandardBridge_BridgeERC20To_Test:test_withdrawTo_withdrawingERC20_succeeds() (gas: 388045)
 L2StandardBridge_BridgeERC20_Test:test_bridgeERC20_succeeds() (gas: 383520)
 L2StandardBridge_BridgeERC20_Test:test_withdraw_notEOA_reverts() (gas: 251687)
-L2StandardBridge_BridgeERC20_Test:test_withdraw_withdrawingERC20_succeeds() (gas: 383722)
+L2StandardBridge_BridgeERC20_Test:test_withdraw_withdrawingERC20_succeeds() (gas: 383723)
 L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_incorrectValue_reverts() (gas: 23798)
 L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_sendToMessenger_reverts() (gas: 23960)
 L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_sendToSelf_reverts() (gas: 23848)
-L2StandardBridge_Bridge_Test:test_finalizeDeposit_depositingERC20_succeeds() (gas: 91011)
-L2StandardBridge_Bridge_Test:test_finalizeDeposit_depositingETH_succeeds() (gas: 89843)
+L2StandardBridge_Bridge_Test:test_finalizeDeposit_depositingERC20_succeeds() (gas: 91013)
+L2StandardBridge_Bridge_Test:test_finalizeDeposit_depositingETH_succeeds() (gas: 89845)
 L2StandardBridge_FinalizeBridgeETH_Test:test_finalizeBridgeETH_succeeds() (gas: 43155)
 L2StandardBridge_Test:test_initialize_succeeds() (gas: 24247)
-L2StandardBridge_Test:test_receive_succeeds() (gas: 177167)
-L2StandardBridge_Test:test_withdraw_insufficientValue_reverts() (gas: 19637)
+L2StandardBridge_Test:test_receive_succeeds() (gas: 173990)
+L2StandardBridge_Test:test_withdraw_ether_succeeds() (gas: 140500)
+L2StandardBridge_Test:test_withdraw_insufficientValue_reverts() (gas: 16463)
 L2ToL1MessagePasserTest:test_burn_succeeds() (gas: 112572)
 L2ToL1MessagePasserTest:test_initiateWithdrawal_fromContract_succeeds() (gas: 70423)
 L2ToL1MessagePasserTest:test_initiateWithdrawal_fromEOA_succeeds() (gas: 75874)

packages/contracts-bedrock/contracts/L2/L2StandardBridge.sol

@@ -85,6 +85,8 @@ contract L2StandardBridge is StandardBridge, Semver {
     /**
      * @custom:legacy
      * @notice Initiates a withdrawal from L2 to L1.
+     *         This function only works with OptimismMintableERC20 tokens or ether. Use the
+     *         `bridgeERC20` function to bridge native L2 tokens to L1.
      *
      * @param _l2Token     Address of the L2 token to withdraw.
      * @param _amount      Amount of the L2 token to withdraw.
@@ -107,6 +109,8 @@ contract L2StandardBridge is StandardBridge, Semver {
      *         be locked in the L1StandardBridge. ETH may be recoverable if the call can be
      *         successfully replayed by increasing the amount of gas supplied to the call. If the
      *         call will fail for any amount of gas, then the ETH will be locked permanently.
+     *         This function only works with OptimismMintableERC20 tokens or ether. Use the
+     *         `bridgeERC20To` function to bridge native L2 tokens to L1.
      *
      * @param _l2Token     Address of the L2 token to withdraw.
      * @param _to          Recipient account on L1.
@@ -126,7 +130,8 @@ contract L2StandardBridge is StandardBridge, Semver {
 
     /**
      * @custom:legacy
-     * @notice Finalizes a deposit from L1 to L2.
+     * @notice Finalizes a deposit from L1 to L2. To finalize a deposit of ether, use address(0)
+     *         and the l1Token and the Legacy ERC20 ether predeploy address as the l2Token.
      *
      * @param _l1Token   Address of the L1 token to deposit.
      * @param _l2Token   Address of the corresponding L2 token.
@@ -179,10 +184,10 @@ contract L2StandardBridge is StandardBridge, Semver {
         uint32 _minGasLimit,
         bytes memory _extraData
     ) internal {
-        address l1Token = OptimismMintableERC20(_l2Token).l1Token();
         if (_l2Token == Predeploys.LEGACY_ERC20_ETH) {
             _initiateBridgeETH(_from, _to, _amount, _minGasLimit, _extraData);
         } else {
+            address l1Token = OptimismMintableERC20(_l2Token).l1Token();
             _initiateBridgeERC20(_l2Token, l1Token, _from, _to, _amount, _minGasLimit, _extraData);
         }
     }

packages/contracts-bedrock/contracts/test/L2StandardBridge.t.sol

@@ -118,6 +118,38 @@ contract L2StandardBridge_Test is Bridge_Initializer {
         vm.prank(alice, alice);
         L2Bridge.withdraw(address(Predeploys.LEGACY_ERC20_ETH), 100, 1000, hex"");
     }
+
+    /**
+     * @notice Use the legacy `withdraw` interface on the L2StandardBridge to
+     *         withdraw ether from L2 to L1.
+     */
+    function test_withdraw_ether_succeeds() external {
+        assertTrue(alice.balance >= 100);
+        assertEq(Predeploys.L2_TO_L1_MESSAGE_PASSER.balance, 0);
+
+        vm.expectEmit(true, true, true, true, address(L2Bridge));
+        emit WithdrawalInitiated({
+            l1Token: address(0),
+            l2Token: Predeploys.LEGACY_ERC20_ETH,
+            from: alice,
+            to: alice,
+            amount: 100,
+            data: hex""
+        });
+
+        vm.expectEmit(true, true, true, true, address(L2Bridge));
+        emit ETHBridgeInitiated({ from: alice, to: alice, amount: 100, data: hex"" });
+
+        vm.prank(alice, alice);
+        L2Bridge.withdraw{ value: 100 }({
+            _l2Token: Predeploys.LEGACY_ERC20_ETH,
+            _amount: 100,
+            _minGasLimit: 1000,
+            _extraData: hex""
+        });
+
+        assertEq(Predeploys.L2_TO_L1_MESSAGE_PASSER.balance, 100);
+    }
 }
 
 contract PreBridgeERC20 is Bridge_Initializer {