Allow null in some fields for eth_sendTransaction (#33564)

components/brave_wallet/common/eth_request_helper.cc

@@ -130,11 +130,22 @@ mojom::TxData1559Ptr ParseEthTransaction1559Params(
 
   tx_data->base_data = std::move(base_data_ret);
 
+  // MM accepts `null` in these fields as no value:
+  // https://github.com/MetaMask/core/blob/5d9dec2085607b9dbf7667e328a16a5652da07fa/packages/transaction-controller/src/utils/validation.ts#L374-L395
   if (tx->max_priority_fee_per_gas) {
-    tx_data->max_priority_fee_per_gas = *tx->max_priority_fee_per_gas;
+    if (tx->max_priority_fee_per_gas->is_string()) {
+      tx_data->max_priority_fee_per_gas =
+          tx->max_priority_fee_per_gas->GetString();
+    } else if (!tx->max_priority_fee_per_gas->is_none()) {
+      return nullptr;
+    }
   }
   if (tx->max_fee_per_gas) {
-    tx_data->max_fee_per_gas = *tx->max_fee_per_gas;
+    if (tx->max_fee_per_gas->is_string()) {
+      tx_data->max_fee_per_gas = tx->max_fee_per_gas->GetString();
+    } else if (!tx->max_fee_per_gas->is_none()) {
+      return nullptr;
+    }
   }
 
   return tx_data;

components/brave_wallet/common/eth_request_helper_unittest.cc

@@ -137,6 +137,41 @@ TEST(EthResponseHelperUnitTest, ParseEthTransaction1559Params) {
   EXPECT_TRUE(tx_data->max_fee_per_gas.empty());
 }
 
+TEST(EthResponseHelperUnitTest, ParseEthTransaction1559ParamsHandleNulls) {
+  std::string json(
+      R"({
+        "params": [{
+          "from": "0x7f84E0DfF3ffd0af78770cF86c1b1DdFF99d51C8",
+          "to": "0x7f84E0DfF3ffd0af78770cF86c1b1DdFF99d51C7",
+          "gas": "0x146",
+          "value": "0x25F38E9E0000000",
+          "data": "0x010203",
+          "nonce": "0x01",
+        }]
+      })");
+  auto params = ParseParamsList(json);
+  std::string from;
+  mojom::TxData1559Ptr tx_data = ParseEthTransaction1559Params(params, from);
+  EXPECT_EQ(tx_data->max_fee_per_gas, "");
+  EXPECT_EQ(tx_data->max_priority_fee_per_gas, "");
+
+  // nulls in these fields are parsed as no value.
+  params[0].GetDict().Set("maxFeePerGas", base::Value());
+  params[0].GetDict().Set("maxPriorityFeePerGas", base::Value());
+
+  tx_data = ParseEthTransaction1559Params(params, from);
+  EXPECT_EQ(tx_data->max_fee_per_gas, "");
+  EXPECT_EQ(tx_data->max_priority_fee_per_gas, "");
+
+  // Non string values fail parsing.
+  params[0].GetDict().Set("maxFeePerGas", base::Value(123));
+  EXPECT_FALSE(ParseEthTransaction1559Params(params, from));
+  params[0].GetDict().Set("maxFeePerGas", base::Value());
+
+  params[0].GetDict().Set("maxPriorityFeePerGas", base::DictValue());
+  EXPECT_FALSE(ParseEthTransaction1559Params(params, from));
+}
+
 TEST(EthResponseHelperUnitTest, ShouldCreate1559Tx) {
   // Test both EIP1559 and legacy gas fee fields are specified.
   std::string json(

components/brave_wallet/common/json_rpc_requests.idl

@@ -13,7 +13,7 @@ namespace json_rpc_requests {
     DOMString? value;
     DOMString? data;
     DOMString? nonce;
-    DOMString? maxPriorityFeePerGas;
-    DOMString? maxFeePerGas;
+    any? maxPriorityFeePerGas;
+    any? maxFeePerGas;
   };
 };