From 75ab854badb52f2da0d161f7e3747dbbf688a2ae Mon Sep 17 00:00:00 2001
From: Erik Zhang <erik@neo.org>
Date: Thu, 5 Aug 2021 16:08:08 +0800
Subject: [PATCH] Revert "Refuel (#2444)" (#2560)

---
 src/neo/SmartContract/ApplicationEngine.cs    | 10 +--
 src/neo/SmartContract/Native/GasToken.cs      | 12 ----
 .../SmartContract/Native/UT_GasToken.cs       | 62 -------------------
 3 files changed, 1 insertion(+), 83 deletions(-)

diff --git a/src/neo/SmartContract/ApplicationEngine.cs b/src/neo/SmartContract/ApplicationEngine.cs
index e0f0db6266..b7135ed055 100644
--- a/src/neo/SmartContract/ApplicationEngine.cs
+++ b/src/neo/SmartContract/ApplicationEngine.cs
@@ -40,7 +40,7 @@ public partial class ApplicationEngine : ExecutionEngine
 
         private static IApplicationEngineProvider applicationEngineProvider;
         private static Dictionary<uint, InteropDescriptor> services;
-        private long gas_amount;
+        private readonly long gas_amount;
         private List<NotifyEventArgs> notifications;
         private List<IDisposable> disposables;
         private readonly Dictionary<UInt160, int> invocationCounter = new();
@@ -156,14 +156,6 @@ protected internal void AddGas(long gas)
                 throw new InvalidOperationException("Insufficient GAS.");
         }
 
-        internal void Refuel(long gas)
-        {
-            checked
-            {
-                gas_amount += gas;
-            }
-        }
-
         protected override void OnFault(Exception ex)
         {
             FaultException = ex;
diff --git a/src/neo/SmartContract/Native/GasToken.cs b/src/neo/SmartContract/Native/GasToken.cs
index 814992f74f..51cbb6dbaa 100644
--- a/src/neo/SmartContract/Native/GasToken.cs
+++ b/src/neo/SmartContract/Native/GasToken.cs
@@ -1,8 +1,5 @@
-#pragma warning disable IDE0051
-
 using Neo.Cryptography.ECC;
 using Neo.Network.P2P.Payloads;
-using System;
 
 namespace Neo.SmartContract.Native
 {
@@ -36,14 +33,5 @@ internal override async ContractTask OnPersist(ApplicationEngine engine)
             UInt160 primary = Contract.CreateSignatureRedeemScript(validators[engine.PersistingBlock.PrimaryIndex]).ToScriptHash();
             await Mint(engine, primary, totalNetworkFee, false);
         }
-
-        [ContractMethod(CpuFee = 1 << 15, RequiredCallFlags = CallFlags.States | CallFlags.AllowNotify)]
-        private async ContractTask Refuel(ApplicationEngine engine, UInt160 account, long amount)
-        {
-            if (amount < 0) throw new ArgumentOutOfRangeException(nameof(amount));
-            if (!engine.CheckWitnessInternal(account)) throw new InvalidOperationException();
-            await Burn(engine, account, amount);
-            engine.Refuel(amount);
-        }
     }
 }
diff --git a/tests/neo.UnitTests/SmartContract/Native/UT_GasToken.cs b/tests/neo.UnitTests/SmartContract/Native/UT_GasToken.cs
index 4bcd2e143f..0b1f4be296 100644
--- a/tests/neo.UnitTests/SmartContract/Native/UT_GasToken.cs
+++ b/tests/neo.UnitTests/SmartContract/Native/UT_GasToken.cs
@@ -6,7 +6,6 @@
 using Neo.SmartContract;
 using Neo.SmartContract.Native;
 using Neo.UnitTests.Extensions;
-using Neo.VM;
 using System;
 using System.Linq;
 using System.Numerics;
@@ -36,67 +35,6 @@ public void TestSetup()
         [TestMethod]
         public void Check_Decimals() => NativeContract.GAS.Decimals(_snapshot).Should().Be(8);
 
-        [TestMethod]
-        public void Refuel()
-        {
-            // Prepare
-
-            var wallet = TestUtils.GenerateTestWallet();
-            var snapshot = TestBlockchain.GetTestSnapshot();
-
-            using var unlock = wallet.Unlock("");
-            var accBalance = wallet.CreateAccount();
-            var accNoBalance = wallet.CreateAccount();
-
-            // Fake balance
-
-            var key = NativeContract.GAS.CreateStorageKey(20, accNoBalance.ScriptHash);
-            var entry = snapshot.GetAndChange(key, () => new StorageItem(new AccountState()));
-            entry.GetInteroperable<AccountState>().Balance = 1 * NativeContract.GAS.Factor;
-
-            key = NativeContract.GAS.CreateStorageKey(20, accBalance.ScriptHash);
-            entry = snapshot.GetAndChange(key, () => new StorageItem(new AccountState()));
-            entry.GetInteroperable<AccountState>().Balance = 100 * NativeContract.GAS.Factor;
-
-            snapshot.Commit();
-
-            // Make transaction
-
-            byte[] script;
-            using (ScriptBuilder sb = new())
-            {
-                sb.EmitDynamicCall(NativeContract.GAS.Hash, "refuel", accBalance.ScriptHash, 100 * NativeContract.GAS.Factor);
-                sb.Emit(OpCode.DROP);
-                sb.EmitSysCall(ApplicationEngine.System_Runtime_GasLeft);
-                script = sb.ToArray();
-            }
-
-            var signers = new Signer[]{ new Signer
-                {
-                    Account = accBalance.ScriptHash,
-                    Scopes =  WitnessScope.CalledByEntry
-                } ,
-                new Signer
-                {
-                    Account = accNoBalance.ScriptHash,
-                    Scopes =  WitnessScope.CalledByEntry
-                } };
-
-            var tx = wallet.MakeTransaction(snapshot, script, accBalance.ScriptHash, signers);
-            Assert.IsNotNull(tx);
-
-            // Check
-
-            using ApplicationEngine engine = ApplicationEngine.Create(TriggerType.Application, tx, snapshot, settings: TestBlockchain.TheNeoSystem.Settings, gas: tx.NetworkFee);
-            engine.LoadScript(tx.Script);
-            Assert.AreEqual(VMState.HALT, engine.Execute());
-            Assert.AreEqual(1, engine.ResultStack.Count);
-            Assert.AreEqual(100_00300140, engine.ResultStack.Pop().GetInteger());
-
-            entry = snapshot.GetAndChange(key, () => new StorageItem(new AccountState()));
-            Assert.AreEqual(0, entry.GetInteroperable<AccountState>().Balance);
-        }
-
         [TestMethod]
         public async Task Check_BalanceOfTransferAndBurn()
         {