fix: check msg.value is zero when payByApp is true

src/lzApp/OAppSenderUpgradeable.sol

@@ -19,7 +19,7 @@ abstract contract OAppSenderUpgradeable is OAppCoreUpgradeable {
     using SafeERC20 for IERC20;
 
     // Custom error messages
-    error NotExactNativeFee(uint256 msgValue);
+    error IncorrectNativeFee(uint256 msgValue);
     error LzTokenUnavailable();
 
     // @dev The version of the OAppSender implementation.
@@ -70,7 +70,7 @@ abstract contract OAppSenderUpgradeable is OAppCoreUpgradeable {
      *      - nativeFee: The native fee.
      *      - lzTokenFee: The lzToken fee.
      * @param _refundAddress The address to receive any excess fee values sent to the endpoint.
-     * @param byApp Whether the native fee is paid by the app itself or by the app caller,
+     * @param payByApp Whether the native fee is paid by the app itself or by the app caller,
      * if byApp is true, app caller does not need to specify msg.value to pay for the native fee.
      * @return receipt The receipt for the sent message.
      *      - guid: The unique identifier for the sent message.
@@ -83,11 +83,11 @@ abstract contract OAppSenderUpgradeable is OAppCoreUpgradeable {
         bytes memory _options,
         MessagingFee memory _fee,
         address _refundAddress,
-        bool byApp
+        bool payByApp
     ) internal virtual returns (MessagingReceipt memory receipt) {
         // @dev Push corresponding fees to the endpoint, any excess is sent back to the _refundAddress from the
         // endpoint.
-        uint256 messageValue = _payNative(_fee.nativeFee, byApp);
+        uint256 messageValue = _payNative(_fee.nativeFee, payByApp);
         if (_fee.lzTokenFee > 0) {
             _payLzToken(_fee.lzTokenFee);
         }
@@ -102,7 +102,7 @@ abstract contract OAppSenderUpgradeable is OAppCoreUpgradeable {
     /**
      * @dev Internal function to pay the native fee associated with the message.
      * @param _nativeFee The native fee to be paid.
-     * @param byApp Whether the native fee is paid by the app itself or by the app caller,
+     * @param payByApp Whether the native fee is paid by the app itself or by the app caller,
      * if byApp is true, do not check that the msg.value is equal to nativeFee.
      * @return nativeFee The amount of native currency paid.
      *
@@ -112,9 +112,9 @@ abstract contract OAppSenderUpgradeable is OAppCoreUpgradeable {
      * @dev Some EVMs use an ERC20 as a method for paying transactions/gasFees.
      * @dev The endpoint is EITHER/OR, ie. it will NOT support both types of native payment at a time.
      */
-    function _payNative(uint256 _nativeFee, bool byApp) internal virtual returns (uint256 nativeFee) {
-        if (!byApp && msg.value != _nativeFee) {
-            revert NotExactNativeFee(msg.value);
+    function _payNative(uint256 _nativeFee, bool payByApp) internal virtual returns (uint256 nativeFee) {
+        if ((!payByApp && msg.value != _nativeFee) || (payByApp && msg.value != 0)) {
+            revert IncorrectNativeFee(msg.value);
         }
         return _nativeFee;
     }