From b26362372f29f2b51277b2815f3010f41d4b2a7c Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Tue, 18 Jun 2024 16:45:55 +0900
Subject: [PATCH 01/11] Changed to always store next state root hash

---
 Libplanet/Blockchain/BlockChain.cs | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/Libplanet/Blockchain/BlockChain.cs b/Libplanet/Blockchain/BlockChain.cs
index 49d387bf934..1bbdab67537 100644
--- a/Libplanet/Blockchain/BlockChain.cs
+++ b/Libplanet/Blockchain/BlockChain.cs
@@ -185,18 +185,19 @@ private BlockChain(
 
             if (Tip.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
             {
-                return;
+                Store.PutNextStateRootHash(Tip.Hash, Tip.StateRootHash);
             }
+            else
+            {
+                HashDigest<SHA256> nextStateRootHash =
+                    DetermineNextBlockStateRootHash(Tip, out var actionEvaluations);
 
-            HashDigest<SHA256> nextStateRootHash =
-                DetermineNextBlockStateRootHash(Tip, out var actionEvaluations);
-
-            Store.DeleteNextStateRootHash(Tip.Hash);
-            Store.PutNextStateRootHash(Tip.Hash, nextStateRootHash);
+                Store.DeleteNextStateRootHash(Tip.Hash);
+                Store.PutNextStateRootHash(Tip.Hash, nextStateRootHash);
 
-            IEnumerable<TxExecution> txExecutions =
-                MakeTxExecutions(Tip, actionEvaluations);
-            UpdateTxExecutions(txExecutions);
+                IEnumerable<TxExecution> txExecutions = MakeTxExecutions(Tip, actionEvaluations);
+                UpdateTxExecutions(txExecutions);
+            }
         }
 
         ~BlockChain()
@@ -1159,6 +1160,7 @@ internal void AppendStateRootHashPreceded(
                                 TimestampFormat, CultureInfo.InvariantCulture));
 
                     _blocks[block.Hash] = block;
+                    Store.PutNextStateRootHash(block.Hash, block.StateRootHash);
                     IEnumerable<TxExecution> txExecutions =
                         MakeTxExecutions(block, actionEvaluations);
                     UpdateTxExecutions(txExecutions);

From fd99513f4d93d7f069d57722baaa8b1e3f049480 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Tue, 18 Jun 2024 19:36:05 +0900
Subject: [PATCH 02/11] Added extension methods for test codes

---
 Libplanet.Tests/BlockChainExtensions.cs | 73 +++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 Libplanet.Tests/BlockChainExtensions.cs

diff --git a/Libplanet.Tests/BlockChainExtensions.cs b/Libplanet.Tests/BlockChainExtensions.cs
new file mode 100644
index 00000000000..da010032987
--- /dev/null
+++ b/Libplanet.Tests/BlockChainExtensions.cs
@@ -0,0 +1,73 @@
+using System.Security.Cryptography;
+using Libplanet.Action.State;
+using Libplanet.Blockchain;
+using Libplanet.Common;
+using Libplanet.Types.Blocks;
+
+namespace Libplanet.Tests
+{
+    public static class BlockChainExtensions
+    {
+        public static Block GetNextBlock(this BlockChain blockChain, BlockHash blockHash) =>
+            blockChain[blockChain[blockHash].Index + 1];
+
+        /// <summary>
+        /// Returns an <see cref="IWorldState"/> resulting from the execution of
+        /// the tip of <paramref name="blockChain"/>.
+        /// </summary>
+        /// <param name="blockChain">The <see cref="BlockChain"/> to search.</param>
+        /// <returns>An <see cref="IWorldState"/> resulting from the execution of
+        /// the tip of <paramref name="blockChain"/>.</returns>
+        public static IWorldState GetResultWorldState(this BlockChain blockChain) =>
+            GetResultWorldState(blockChain, blockChain.Tip);
+
+        /// <summary>
+        /// Returns an <see cref="IWorldState"/> resulting from the execution of
+        /// a <see cref="Block"/> associated with given <paramref name="index"/>
+        /// from <paramref name="blockChain"/>.
+        /// </summary>
+        /// <param name="blockChain">The <see cref="BlockChain"/> to search.</param>
+        /// <param name="index">The index of a <see cref="Block"/> to search.</param>
+        /// <returns>An <see cref="IWorldState"/> resulting from the execution of
+        /// a <see cref="Block"/> associated with given <paramref name="index"/>.</returns>
+        public static IWorldState GetResultWorldState(this BlockChain blockChain, long index) =>
+            GetResultWorldState(blockChain, blockChain[index]);
+
+        /// <summary>
+        /// Returns an <see cref="IWorldState"/> resulting from the execution of
+        /// a <see cref="Block"/> associated with given <paramref name="blockHash"/>
+        /// from <paramref name="blockChain"/>.
+        /// </summary>
+        /// <param name="blockChain">The <see cref="BlockChain"/> to search.</param>
+        /// <param name="blockHash">The <see cref="BlockHash"/> to search.</param>
+        /// <returns>An <see cref="IWorldState"/> resulting from the execution of
+        /// a <see cref="Block"/> associated with given <paramref name="blockHash"/>.</returns>
+        public static IWorldState GetResultWorldState(
+            this BlockChain blockChain,
+            BlockHash blockHash) =>
+            GetResultWorldState(blockChain, blockChain[blockHash]);
+
+        private static IWorldState GetResultWorldState(BlockChain blockChain, Block block)
+        {
+            if (block.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
+            {
+                return blockChain.GetWorldState(block.StateRootHash);
+            }
+            else
+            {
+                // Since block is fetched from blockChain, its index will be at most tip's index.
+                if (block.Index < blockChain.Tip.Index)
+                {
+                    return blockChain.GetWorldState(blockChain[block.Index + 1].StateRootHash);
+                }
+                else
+                {
+                    return blockChain.GetNextStateRootHash(block.Hash) is
+                        HashDigest<SHA256> stateRootHash
+                            ? blockChain.GetWorldState(stateRootHash)
+                            : null;
+                }
+            }
+        }
+    }
+}

From 8e1306cc9839a5ad2812b1ba888e1035042b1de9 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Tue, 18 Jun 2024 20:01:14 +0900
Subject: [PATCH 03/11] Rerouted calls to extension methods

---
 Libplanet.Net.Tests/Consensus/ContextTest.cs  |  5 ++--
 Libplanet.Net.Tests/TestUtils.cs              |  3 ++-
 .../Blockchain/BlockChainTest.Append.cs       |  4 +--
 Libplanet.Tests/Blockchain/BlockChainTest.cs  |  4 +--
 Libplanet/Blockchain/BlockChain.States.cs     | 27 ++++---------------
 5 files changed, 14 insertions(+), 29 deletions(-)

diff --git a/Libplanet.Net.Tests/Consensus/ContextTest.cs b/Libplanet.Net.Tests/Consensus/ContextTest.cs
index d66f03c7ee9..d701322a276 100644
--- a/Libplanet.Net.Tests/Consensus/ContextTest.cs
+++ b/Libplanet.Net.Tests/Consensus/ContextTest.cs
@@ -16,6 +16,7 @@
 using Libplanet.Net.Messages;
 using Libplanet.Store;
 using Libplanet.Store.Trie;
+using Libplanet.Tests;
 using Libplanet.Tests.Store;
 using Libplanet.Types.Blocks;
 using Libplanet.Types.Consensus;
@@ -321,7 +322,7 @@ void BroadcastMessage(ConsensusMsg message) =>
                 1L,
                 TestUtils.PrivateKeys[0],
                 blockChain
-                    .GetNextWorldState(blockChain[0L].Hash)!
+                    .GetResultWorldState(0)
                     .GetValidatorSet(),
                 contextTimeoutOptions: new ContextTimeoutOption());
 
@@ -623,7 +624,7 @@ void BroadcastMessage(ConsensusMsg message) =>
                 1L,
                 TestUtils.PrivateKeys[0],
                 blockChain
-                    .GetNextWorldState(blockChain[0L].Hash)!
+                    .GetResultWorldState(0L)
                     .GetValidatorSet(),
                 contextTimeoutOptions: new ContextTimeoutOption());
 
diff --git a/Libplanet.Net.Tests/TestUtils.cs b/Libplanet.Net.Tests/TestUtils.cs
index ffe72a2c1a6..a83c00fea82 100644
--- a/Libplanet.Net.Tests/TestUtils.cs
+++ b/Libplanet.Net.Tests/TestUtils.cs
@@ -19,6 +19,7 @@
 using Libplanet.Net.Transports;
 using Libplanet.Store;
 using Libplanet.Store.Trie;
+using Libplanet.Tests;
 using Libplanet.Tests.Store;
 using Libplanet.Types.Blocks;
 using Libplanet.Types.Consensus;
@@ -288,7 +289,7 @@ void BroadcastMessage(ConsensusMsg message) =>
                 height,
                 privateKey,
                 validatorSet ?? blockChain
-                    .GetNextWorldState(blockChain[height - 1].Hash)!
+                    .GetResultWorldState(height - 1)
                     .GetValidatorSet(),
                 contextTimeoutOptions: contextTimeoutOptions ?? new ContextTimeoutOption());
 
diff --git a/Libplanet.Tests/Blockchain/BlockChainTest.Append.cs b/Libplanet.Tests/Blockchain/BlockChainTest.Append.cs
index 333ac0b00e6..a731556927d 100644
--- a/Libplanet.Tests/Blockchain/BlockChainTest.Append.cs
+++ b/Libplanet.Tests/Blockchain/BlockChainTest.Append.cs
@@ -786,10 +786,10 @@ public void DoesNotMigrateStateWithoutAction()
                 ImmutableList<Transaction>.Empty,
                 TestUtils.CreateBlockCommit(blockChain.Tip));
             blockChain.Append(emptyBlock, TestUtils.CreateBlockCommit(emptyBlock));
-            Assert.True(blockChain.GetNextWorldState(emptyBlock.Hash).Legacy);
+            Assert.True(blockChain.GetResultWorldState(emptyBlock.Hash).Legacy);
             Assert.Equal<byte>(
                 blockChain.GetWorldState(genesis.StateRootHash).Trie.Hash.ByteArray,
-                blockChain.GetNextWorldState(emptyBlock.Hash).Trie.Hash.ByteArray);
+                blockChain.GetResultWorldState(emptyBlock.Hash).Trie.Hash.ByteArray);
         }
 
         [Fact]
diff --git a/Libplanet.Tests/Blockchain/BlockChainTest.cs b/Libplanet.Tests/Blockchain/BlockChainTest.cs
index 781103239c3..a7d4e511af0 100644
--- a/Libplanet.Tests/Blockchain/BlockChainTest.cs
+++ b/Libplanet.Tests/Blockchain/BlockChainTest.cs
@@ -2316,7 +2316,7 @@ private void ValidateNextBlockCommitOnValidatorSetChange()
 
             Assert.Equal(
                 blockChain
-                    .GetNextWorldState(blockChain[0].Hash)
+                    .GetResultWorldState(0)
                     .GetValidatorSet(),
                 new ValidatorSet(
                     ValidatorPrivateKeys.Select(
@@ -2324,7 +2324,7 @@ private void ValidateNextBlockCommitOnValidatorSetChange()
 
             Assert.Equal(
                 blockChain
-                    .GetNextWorldState(blockChain[1].Hash)
+                    .GetResultWorldState(1)
                     .GetValidatorSet(),
                 new ValidatorSet(
                     newValidators.Select(
diff --git a/Libplanet/Blockchain/BlockChain.States.cs b/Libplanet/Blockchain/BlockChain.States.cs
index efa27efbec7..1879dd712d5 100644
--- a/Libplanet/Blockchain/BlockChain.States.cs
+++ b/Libplanet/Blockchain/BlockChain.States.cs
@@ -2,7 +2,6 @@
 using System.Security.Cryptography;
 using Libplanet.Action.State;
 using Libplanet.Common;
-using Libplanet.Store;
 using Libplanet.Types.Blocks;
 
 namespace Libplanet.Blockchain
@@ -27,33 +26,17 @@ public IWorldState GetWorldState(HashDigest<SHA256>? stateRootHash)
         /// Gets the next world state in the <see cref="BlockChain"/>.
         /// </summary>
         /// <returns>The next world state.  If it does not exist, returns null.</returns>
-        public IWorldState? GetNextWorldState() => GetNextWorldState(Tip.Hash);
-
-        /// <summary>
-        /// Returns the next <see cref="IWorldState"/> in the BlockChain
-        /// at <paramref name="offset"/>.
-        /// </summary>
-        /// <param name="offset">The <see cref="BlockHash"/> of the <see cref="Block"/> to create
-        /// for which to create an <see cref="IWorldState"/>.</param>
-        /// <returns>
-        /// The next <see cref="IWorldState"/> at <paramref name="offset"/>.
-        /// Returns <see langword="null"/> if next state root hash does not exists.
-        /// </returns>
-        /// <exception cref="ArgumentException">Thrown when next state root hash exists,
-        /// but corresponding state root is not found in the <see cref="IStateStore"/>.
-        /// </exception>
-        /// <seealso cref="IWorldState"/>
-        public IWorldState? GetNextWorldState(BlockHash offset)
+        public IWorldState? GetNextWorldState()
         {
-            var nextSrh = Store.GetNextStateRootHash(offset);
+            var nextSrh = Store.GetNextStateRootHash(Tip.Hash);
             if (nextSrh is { } srh)
             {
                 var trie = StateStore.GetStateRoot(srh);
                 return trie.Recorded
                     ? new WorldBaseState(StateStore.GetStateRoot(nextSrh), StateStore)
-                    : throw new ArgumentException(
-                        $"Could not find state root {srh} in {nameof(StateStore)}.",
-                        nameof(offset));
+                    : throw new InvalidOperationException(
+                        $"Could not find state root {srh} in {nameof(StateStore)} for " +
+                        $"the current tip.");
             }
             else
             {

From fe1726b22245ce2bb3431141e783ceb633a54430 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Wed, 19 Jun 2024 11:17:33 +0900
Subject: [PATCH 04/11] Changed validation and proposal to throw an exception
 instead of blocking

---
 Libplanet/Blockchain/BlockChain.ProposeBlock.cs | 5 ++++-
 Libplanet/Blockchain/BlockChain.Validate.cs     | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/Libplanet/Blockchain/BlockChain.ProposeBlock.cs b/Libplanet/Blockchain/BlockChain.ProposeBlock.cs
index e831b2f55bb..1b665fdfad3 100644
--- a/Libplanet/Blockchain/BlockChain.ProposeBlock.cs
+++ b/Libplanet/Blockchain/BlockChain.ProposeBlock.cs
@@ -149,7 +149,10 @@ internal Block ProposeBlock(
                 _blocks[prevHash].ProtocolVersion <
                 BlockMetadata.SlothProtocolVersion
                     ? _blocks[prevHash].StateRootHash
-                    : (HashDigest<SHA256>)GetNextStateRootHash(prevHash, TimeSpan.Zero);
+                    : GetNextStateRootHash(prevHash) ??
+                        throw new InvalidOperationException(
+                            $"Cannot propose a block as the next state root hash " +
+                            $"for block {prevHash} is missing.");
 
             // FIXME: Should use automated public constructor.
             // Manual internal constructor is used purely for testing custom timestamps.
diff --git a/Libplanet/Blockchain/BlockChain.Validate.cs b/Libplanet/Blockchain/BlockChain.Validate.cs
index 803c5bdd468..f39a10318b8 100644
--- a/Libplanet/Blockchain/BlockChain.Validate.cs
+++ b/Libplanet/Blockchain/BlockChain.Validate.cs
@@ -343,7 +343,10 @@ internal void ValidateBlockStateRootHash(Block block, TimeSpan validationInterva
                 _blocks[previousHash].ProtocolVersion <
                 BlockMetadata.SlothProtocolVersion
                     ? _blocks[previousHash].StateRootHash
-                    : (HashDigest<SHA256>)GetNextStateRootHash(previousHash, validationInterval);
+                    : GetNextStateRootHash(previousHash) ??
+                        throw new InvalidOperationException(
+                            $"Cannot validate a block' state root hash as the next " +
+                            $"state root hash for block {previousHash} is missing.");
 
             if (!stateRootHash.Equals(block.StateRootHash))
             {

From 91478ceccfbfa6c507d962aae938ccbd3ce085c5 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Wed, 19 Jun 2024 13:48:12 +0900
Subject: [PATCH 05/11] Refactor GetNextStateRootHash

---
 Libplanet.Net/Consensus/ConsensusContext.cs   | 19 +++++++---
 Libplanet.Net/Consensus/Context.cs            |  2 +-
 .../Blockchain/BlockChain.ProposeBlock.cs     | 12 +++----
 Libplanet/Blockchain/BlockChain.States.cs     |  2 +-
 Libplanet/Blockchain/BlockChain.Validate.cs   | 22 ++++++------
 Libplanet/Blockchain/BlockChain.cs            | 35 ++++++++++---------
 6 files changed, 48 insertions(+), 44 deletions(-)

diff --git a/Libplanet.Net/Consensus/ConsensusContext.cs b/Libplanet.Net/Consensus/ConsensusContext.cs
index cb70301f067..f695fd365ba 100644
--- a/Libplanet.Net/Consensus/ConsensusContext.cs
+++ b/Libplanet.Net/Consensus/ConsensusContext.cs
@@ -461,11 +461,20 @@ private Context CreateContext(long height)
             }
             else
             {
-                validatorSet = _blockChain
-                    .GetWorldState(
-                        _blockChain.GetNextStateRootHash(
-                            _blockChain[Height - 1].Hash, TimeSpan.Zero))
-                    .GetValidatorSet();
+                while (true)
+                {
+                    var nextStateRootHash = _blockChain.GetNextStateRootHash(Height - 1);
+                    if (nextStateRootHash is { } nsrh)
+                    {
+                        validatorSet = _blockChain
+                            .GetWorldState(nsrh)
+                            .GetValidatorSet();
+                        break;
+                    }
+
+                    // FIXME: Maybe this should be adjustable?
+                    Thread.Sleep(100);
+                }
             }
 
             Context context = new Context(
diff --git a/Libplanet.Net/Consensus/Context.cs b/Libplanet.Net/Consensus/Context.cs
index f1698b2a6dc..cb6b1b47cb0 100644
--- a/Libplanet.Net/Consensus/Context.cs
+++ b/Libplanet.Net/Consensus/Context.cs
@@ -491,7 +491,7 @@ private bool IsValid(Block block)
                         }
                     }
 
-                    _blockChain.ValidateBlockStateRootHash(block, TimeSpan.Zero);
+                    _blockChain.ValidateBlockStateRootHash(block);
                 }
                 catch (Exception e) when (
                     e is InvalidBlockException ||
diff --git a/Libplanet/Blockchain/BlockChain.ProposeBlock.cs b/Libplanet/Blockchain/BlockChain.ProposeBlock.cs
index 1b665fdfad3..09ef70d94be 100644
--- a/Libplanet/Blockchain/BlockChain.ProposeBlock.cs
+++ b/Libplanet/Blockchain/BlockChain.ProposeBlock.cs
@@ -145,14 +145,10 @@ internal Block ProposeBlock(
             BlockHash prevHash = Store.IndexBlockHash(Id, index - 1)
                 ?? throw new NullReferenceException($"Chain {Id} is missing block #{index - 1}");
 
-            HashDigest<SHA256> stateRootHash =
-                _blocks[prevHash].ProtocolVersion <
-                BlockMetadata.SlothProtocolVersion
-                    ? _blocks[prevHash].StateRootHash
-                    : GetNextStateRootHash(prevHash) ??
-                        throw new InvalidOperationException(
-                            $"Cannot propose a block as the next state root hash " +
-                            $"for block {prevHash} is missing.");
+            HashDigest<SHA256> stateRootHash = GetNextStateRootHash(prevHash) ??
+                throw new InvalidOperationException(
+                    $"Cannot propose a block as the next state root hash " +
+                    $"for block {prevHash} is missing.");
 
             // FIXME: Should use automated public constructor.
             // Manual internal constructor is used purely for testing custom timestamps.
diff --git a/Libplanet/Blockchain/BlockChain.States.cs b/Libplanet/Blockchain/BlockChain.States.cs
index 1879dd712d5..c0725cca2f4 100644
--- a/Libplanet/Blockchain/BlockChain.States.cs
+++ b/Libplanet/Blockchain/BlockChain.States.cs
@@ -28,7 +28,7 @@ public IWorldState GetWorldState(HashDigest<SHA256>? stateRootHash)
         /// <returns>The next world state.  If it does not exist, returns null.</returns>
         public IWorldState? GetNextWorldState()
         {
-            var nextSrh = Store.GetNextStateRootHash(Tip.Hash);
+            var nextSrh = GetNextStateRootHash();
             if (nextSrh is { } srh)
             {
                 var trie = StateStore.GetStateRoot(srh);
diff --git a/Libplanet/Blockchain/BlockChain.Validate.cs b/Libplanet/Blockchain/BlockChain.Validate.cs
index f39a10318b8..a66adfaaffb 100644
--- a/Libplanet/Blockchain/BlockChain.Validate.cs
+++ b/Libplanet/Blockchain/BlockChain.Validate.cs
@@ -318,19 +318,21 @@ internal void ValidateBlock(Block block)
 
         /// <summary>
         /// Validates a result obtained from <see cref="EvaluateBlock"/> by
-        /// comparing the state root hash from <see cref="GetNextStateRootHash"/>
+        /// comparing the state root hash from <see cref="GetNextStateRootHash(BlockHash)"/>
         /// which stores state root hash from <see cref="DetermineNextBlockStateRootHash"/>,
         /// to the one in <paramref name="block"/>.
         /// </summary>
         /// <param name="block">The <see cref="Block"/> to validate against.</param>
-        /// <param name="validationInterval">The interval for fetching calculated state root hash
-        /// from <see cref="Append(Block, BlockCommit)"/>.</param>
+        /// <exception cref="InvalidOperationException">If this method is called
+        /// when the result of <see cref="GetNextStateRootHash(BlockHash)"/>
+        /// is <see langword="null"/>.  This can happen if <paramref name="block"/>
+        /// is an index higher than the tip but its result is not ready yet.</exception>
         /// <exception cref="InvalidBlockStateRootHashException">If the state root hash
         /// calculated by committing to the <see cref="IStateStore"/> does not match
         /// the <paramref name="block"/>'s <see cref="Block.StateRootHash"/>.</exception>
         /// <seealso cref="EvaluateBlock"/>
         /// <seealso cref="DetermineNextBlockStateRootHash"/>
-        internal void ValidateBlockStateRootHash(Block block, TimeSpan validationInterval = default)
+        internal void ValidateBlockStateRootHash(Block block)
         {
             // NOTE: Since previous hash validation is on block validation,
             // assume block is genesis if previous hash is null.
@@ -339,14 +341,10 @@ internal void ValidateBlockStateRootHash(Block block, TimeSpan validationInterva
                 return;
             }
 
-            HashDigest<SHA256> stateRootHash =
-                _blocks[previousHash].ProtocolVersion <
-                BlockMetadata.SlothProtocolVersion
-                    ? _blocks[previousHash].StateRootHash
-                    : GetNextStateRootHash(previousHash) ??
-                        throw new InvalidOperationException(
-                            $"Cannot validate a block' state root hash as the next " +
-                            $"state root hash for block {previousHash} is missing.");
+            HashDigest<SHA256> stateRootHash = GetNextStateRootHash(previousHash) ??
+                throw new InvalidOperationException(
+                    $"Cannot validate a block' state root hash as the next " +
+                    $"state root hash for block {previousHash} is missing.");
 
             if (!stateRootHash.Equals(block.StateRootHash))
             {
diff --git a/Libplanet/Blockchain/BlockChain.cs b/Libplanet/Blockchain/BlockChain.cs
index 1bbdab67537..c99f5fad400 100644
--- a/Libplanet/Blockchain/BlockChain.cs
+++ b/Libplanet/Blockchain/BlockChain.cs
@@ -1405,26 +1405,27 @@ internal void CleanupBlockCommitStore(long limit)
             }
         }
 
-        internal HashDigest<SHA256>? GetNextStateRootHash(
-            BlockHash blockHash,
-            TimeSpan? fetchInterval = null)
+        internal HashDigest<SHA256>? GetNextStateRootHash() =>
+            GetNextStateRootHash(Tip);
+
+        internal HashDigest<SHA256>? GetNextStateRootHash(long index) =>
+            GetNextStateRootHash(this[index]);
+
+        internal HashDigest<SHA256>? GetNextStateRootHash(BlockHash blockHash) =>
+            GetNextStateRootHash(this[blockHash]);
+
+        private HashDigest<SHA256>? GetNextStateRootHash(Block block)
         {
-            while (true)
+            if (block.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
             {
-                if (Store.GetNextStateRootHash(blockHash) is HashDigest<SHA256> srh)
-                {
-                    return srh;
-                }
-
-                if (fetchInterval is TimeSpan interval)
-                {
-                    Thread.Sleep(interval);
-                }
-                else
-                {
-                    return null;
-                }
+                return block.StateRootHash;
             }
+            else if (block.Index < Tip.Index)
+            {
+                return this[block.Index + 1].StateRootHash;
+            }
+
+            return Store.GetNextStateRootHash(block.Hash);
         }
     }
 }

From 3c0c630310609bc2cfff3d0f33251c22de1c179d Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Wed, 19 Jun 2024 16:35:27 +0900
Subject: [PATCH 06/11] Removed next state root hash from storage

---
 Libplanet.Net.Tests/Consensus/ContextTest.cs  |  2 +
 Libplanet.Store/IStore.cs                     | 28 ----------
 Libplanet.Store/MemoryStore.cs                | 14 -----
 .../Action/ActionEvaluatorTest.Migration.cs   |  2 +-
 Libplanet.Tests/Action/ActionEvaluatorTest.cs |  4 +-
 .../Blockchain/BlockChainTest.Internals.cs    |  5 +-
 Libplanet.Tests/Blockchain/BlockChainTest.cs  |  2 -
 Libplanet.Tests/Store/ProxyStore.cs           | 14 -----
 Libplanet.Tests/Store/StoreTest.cs            | 31 -----------
 Libplanet.Tests/Store/StoreTracker.cs         | 20 -------
 Libplanet/Blockchain/BlockChain.Next.cs       | 12 +++++
 Libplanet/Blockchain/BlockChain.States.cs     |  5 +-
 Libplanet/Blockchain/BlockChain.Swap.cs       |  1 +
 Libplanet/Blockchain/BlockChain.cs            | 52 +++++++++----------
 14 files changed, 48 insertions(+), 144 deletions(-)
 create mode 100644 Libplanet/Blockchain/BlockChain.Next.cs

diff --git a/Libplanet.Net.Tests/Consensus/ContextTest.cs b/Libplanet.Net.Tests/Consensus/ContextTest.cs
index d701322a276..a3a464ef807 100644
--- a/Libplanet.Net.Tests/Consensus/ContextTest.cs
+++ b/Libplanet.Net.Tests/Consensus/ContextTest.cs
@@ -2,6 +2,7 @@
 using System.Diagnostics;
 using System.Linq;
 using System.Text.Json;
+using System.Threading;
 using System.Threading.Tasks;
 using Bencodex;
 using Bencodex.Types;
@@ -688,6 +689,7 @@ void BroadcastMessage(ConsensusMsg message) =>
             var watch = Stopwatch.StartNew();
             await onTipChanged.WaitAsync();
             Assert.True(watch.ElapsedMilliseconds < (actionDelay * 0.5));
+            Thread.Sleep(100); // Wait for votes to get collected.
 
             Assert.Equal(
                 4,
diff --git a/Libplanet.Store/IStore.cs b/Libplanet.Store/IStore.cs
index 7edd7d4e318..d273a4bd18e 100644
--- a/Libplanet.Store/IStore.cs
+++ b/Libplanet.Store/IStore.cs
@@ -348,33 +348,5 @@ public interface IStore : IDisposable
         /// <returns>Returns an <see cref="IEnumerable{T}"/> of <see cref="BlockHash"/>es
         /// of all <see cref="BlockCommit"/>s.</returns>
         IEnumerable<BlockHash> GetBlockCommitHashes();
-
-        /// <summary>
-        /// Gets the next state root hash for given <paramref name="blockHash"/> from the store.
-        /// </summary>
-        /// <param name="blockHash">The <see cref="BlockHash"/> of the <see cref="Block"/>
-        /// to retrieve next state root hash.</param>
-        /// <returns>Returns <see cref="HashDigest{SHA256}"/> if next state root hash of given
-        /// <paramref name="blockHash"/> is stored and available,
-        /// otherwise returns <see langword="null"/>.</returns>
-        HashDigest<SHA256>? GetNextStateRootHash(BlockHash blockHash);
-
-        /// <summary>
-        /// Puts a next state root hash of <see cref="Block"/> corresponding to the
-        /// <paramref name="blockHash"/> to the store.
-        /// </summary>
-        /// <param name="blockHash">The <see cref="BlockHash"/> of the <see cref="Block"/>
-        /// where <paramref name="nextStateRootHash"/> evaluated.</param>
-        /// <param name="nextStateRootHash">The <see cref="HashDigest{SHA256}"/> that represents
-        /// state root hash of the next state.</param>
-        void PutNextStateRootHash(BlockHash blockHash, HashDigest<SHA256> nextStateRootHash);
-
-        /// <summary>
-        /// Deletes the next state root hash of <see cref="Block"/> corresponding to the given
-        /// <paramref name="blockHash"/> from the store.
-        /// </summary>
-        /// <param name="blockHash">The <see cref="BlockHash"/> of a next state root hash
-        /// to delete.</param>
-        void DeleteNextStateRootHash(BlockHash blockHash);
     }
 }
diff --git a/Libplanet.Store/MemoryStore.cs b/Libplanet.Store/MemoryStore.cs
index e394b0e266d..43b3a7b916b 100644
--- a/Libplanet.Store/MemoryStore.cs
+++ b/Libplanet.Store/MemoryStore.cs
@@ -301,20 +301,6 @@ public void DeleteBlockCommit(BlockHash blockHash) =>
         public IEnumerable<BlockHash> GetBlockCommitHashes()
             => _blockCommits.Keys;
 
-        /// <inheritdoc />
-        public HashDigest<SHA256>? GetNextStateRootHash(BlockHash blockHash)
-            => _nextStateRootHashes.TryGetValue(blockHash, out var nextStateRootHash)
-                ? (HashDigest<SHA256>?)nextStateRootHash
-                : null;
-
-        /// <inheritdoc />
-        public void PutNextStateRootHash(BlockHash blockHash, HashDigest<SHA256> nextStateRootHash)
-            => _nextStateRootHashes[blockHash] = nextStateRootHash;
-
-        /// <inheritdoc />
-        public void DeleteNextStateRootHash(BlockHash blockHash)
-            => _nextStateRootHashes.TryRemove(blockHash, out _);
-
         [StoreLoader("memory")]
         private static (IStore Store, IStateStore StateStore) Loader(Uri storeUri)
         {
diff --git a/Libplanet.Tests/Action/ActionEvaluatorTest.Migration.cs b/Libplanet.Tests/Action/ActionEvaluatorTest.Migration.cs
index 08035590b2c..0cbec15057a 100644
--- a/Libplanet.Tests/Action/ActionEvaluatorTest.Migration.cs
+++ b/Libplanet.Tests/Action/ActionEvaluatorTest.Migration.cs
@@ -332,7 +332,7 @@ public void MigrateThroughBlockWorldState()
             var block3 = chain.ProposeBlock(miner, blockCommit);
             chain.Append(block3, CreateBlockCommit(block3));
             Assert.Equal(BlockMetadata.CurrentProtocolVersion, chain.GetNextWorldState().Version);
-            var accountStateRoot = stateStore.GetStateRoot(store.GetNextStateRootHash(block3.Hash))
+            var accountStateRoot = stateStore.GetStateRoot(chain.GetNextStateRootHash(block3.Hash))
                 .Get(KeyConverters.ToStateKey(ModernAction.AccountAddress));
             Assert.NotNull(accountStateRoot);
             var accountTrie = stateStore.GetStateRoot(new HashDigest<SHA256>(accountStateRoot));
diff --git a/Libplanet.Tests/Action/ActionEvaluatorTest.cs b/Libplanet.Tests/Action/ActionEvaluatorTest.cs
index 22fc632c1fa..acb72c551d7 100644
--- a/Libplanet.Tests/Action/ActionEvaluatorTest.cs
+++ b/Libplanet.Tests/Action/ActionEvaluatorTest.cs
@@ -1009,7 +1009,7 @@ public void EvaluateActionAndCollectFee()
             Block block = chain.ProposeBlock(miner);
 
             var evaluations = chain.ActionEvaluator.Evaluate(
-                block, chain.Store.GetNextStateRootHash((BlockHash)block.PreviousHash));
+                block, chain.GetNextStateRootHash((BlockHash)block.PreviousHash));
 
             Assert.False(evaluations[0].InputContext.BlockAction);
             Assert.Single(evaluations);
@@ -1079,7 +1079,7 @@ public void EvaluateThrowingExceedGasLimit()
 
             var evaluations = chain.ActionEvaluator.Evaluate(
                 block,
-                chain.Store.GetNextStateRootHash((BlockHash)block.PreviousHash));
+                chain.GetNextStateRootHash((BlockHash)block.PreviousHash));
 
             Assert.False(evaluations[0].InputContext.BlockAction);
             Assert.Single(evaluations);
diff --git a/Libplanet.Tests/Blockchain/BlockChainTest.Internals.cs b/Libplanet.Tests/Blockchain/BlockChainTest.Internals.cs
index 60d0427fd87..caa940dc057 100644
--- a/Libplanet.Tests/Blockchain/BlockChainTest.Internals.cs
+++ b/Libplanet.Tests/Blockchain/BlockChainTest.Internals.cs
@@ -105,8 +105,7 @@ Transaction MkTx(PrivateKey key, long nonce, DateTimeOffset? ts = null) =>
         [SkippableFact]
         public void ExecuteActions()
         {
-            (var addresses, Transaction[] txs) =
-                MakeFixturesForAppendTests();
+            (var addresses, Transaction[] txs) = MakeFixturesForAppendTests();
             var genesis = _blockChain.Genesis;
 
             Block block1 = _blockChain.ProposeBlock(
@@ -126,7 +125,7 @@ public void ExecuteActions()
             };
 
             IValue legacyStateRootRaw =
-                _fx.StateStore.GetStateRoot(_fx.Store.GetNextStateRootHash(block1.Hash))
+                _fx.StateStore.GetStateRoot(_blockChain.GetNextStateRootHash())
                 .Get(ToStateKey(ReservedAddresses.LegacyAccount));
             Assert.NotNull(legacyStateRootRaw);
             var legacyStateRoot =
diff --git a/Libplanet.Tests/Blockchain/BlockChainTest.cs b/Libplanet.Tests/Blockchain/BlockChainTest.cs
index a7d4e511af0..4c6561c9b9c 100644
--- a/Libplanet.Tests/Blockchain/BlockChainTest.cs
+++ b/Libplanet.Tests/Blockchain/BlockChainTest.cs
@@ -1862,8 +1862,6 @@ void BuildIndex(Guid id, Block block)
                         .ToList();
                     Assert.NotEmpty(dirty);
                     store.PutBlock(b);
-                    store.PutNextStateRootHash(
-                        b.Hash, evals.Last().OutputState.Trie.Hash);
                     BuildIndex(chain.Id, b);
                     Assert.Equal(b, chain[b.Hash]);
                     if (presentIndices.Contains((int)b.Index))
diff --git a/Libplanet.Tests/Store/ProxyStore.cs b/Libplanet.Tests/Store/ProxyStore.cs
index cd384d6adb2..dde51f23d54 100644
--- a/Libplanet.Tests/Store/ProxyStore.cs
+++ b/Libplanet.Tests/Store/ProxyStore.cs
@@ -1,7 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Security.Cryptography;
-using Libplanet.Common;
 using Libplanet.Crypto;
 using Libplanet.Store;
 using Libplanet.Types.Blocks;
@@ -191,17 +189,5 @@ public void DeleteBlockCommit(BlockHash blockHash) =>
         /// <inheritdoc cref="IStore.GetBlockCommitHashes"/>
         public IEnumerable<BlockHash> GetBlockCommitHashes() =>
             Store.GetBlockCommitHashes();
-
-        /// <inheritdoc cref="IStore.GetNextStateRootHash"/>
-        public HashDigest<SHA256>? GetNextStateRootHash(BlockHash blockHash) =>
-            Store.GetNextStateRootHash(blockHash);
-
-        /// <inheritdoc cref="IStore.PutNextStateRootHash"/>
-        public void PutNextStateRootHash(BlockHash blockHash, HashDigest<SHA256> nextStateRootHash)
-            => Store.PutNextStateRootHash(blockHash, nextStateRootHash);
-
-        /// <inheritdoc cref="IStore.DeleteNextStateRootHash"/>
-        public void DeleteNextStateRootHash(BlockHash blockHash) =>
-            Store.DeleteNextStateRootHash(blockHash);
     }
 }
diff --git a/Libplanet.Tests/Store/StoreTest.cs b/Libplanet.Tests/Store/StoreTest.cs
index 3adb0d9fd72..1e8f114749e 100644
--- a/Libplanet.Tests/Store/StoreTest.cs
+++ b/Libplanet.Tests/Store/StoreTest.cs
@@ -1169,37 +1169,6 @@ public void DeleteLastCommit()
             }
         }
 
-        [SkippableFact]
-        public void GetNextStateRootHash()
-        {
-            using (StoreFixture fx = FxConstructor())
-            {
-                HashDigest<SHA256> nextStateRootHash
-                    = HashDigest<SHA256>.DeriveFrom(new byte[] { 0, 1, 2 });
-                fx.Store.PutNextStateRootHash(fx.Block2.Hash, nextStateRootHash);
-                HashDigest<SHA256>? storedNextStateRootHash =
-                    fx.Store.GetNextStateRootHash(fx.Block2.Hash);
-
-                Assert.Equal(nextStateRootHash, storedNextStateRootHash);
-            }
-        }
-
-        [SkippableFact]
-        public void DeleteNextStateRootHash()
-        {
-            using (StoreFixture fx = FxConstructor())
-            {
-                HashDigest<SHA256> nextStateRootHash
-                    = HashDigest<SHA256>.DeriveFrom(new byte[] { 0, 1, 2 });
-                fx.Store.PutNextStateRootHash(fx.Block2.Hash, nextStateRootHash);
-
-                Assert.NotNull(fx.Store.GetNextStateRootHash(fx.Block2.Hash));
-
-                fx.Store.DeleteNextStateRootHash(fx.Block2.Hash);
-                Assert.Null(fx.Store.GetNextStateRootHash(fx.Block2.Hash));
-            }
-        }
-
         [SkippableFact]
         public void ForkTxNonces()
         {
diff --git a/Libplanet.Tests/Store/StoreTracker.cs b/Libplanet.Tests/Store/StoreTracker.cs
index f6df855f1c1..c2faff600b1 100644
--- a/Libplanet.Tests/Store/StoreTracker.cs
+++ b/Libplanet.Tests/Store/StoreTracker.cs
@@ -1,7 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Security.Cryptography;
-using Libplanet.Common;
 using Libplanet.Crypto;
 using Libplanet.Store;
 using Libplanet.Types.Blocks;
@@ -232,24 +230,6 @@ public IEnumerable<BlockHash> GetBlockCommitHashes()
             return _store.GetBlockCommitHashes();
         }
 
-        public HashDigest<SHA256>? GetNextStateRootHash(BlockHash blockHash)
-        {
-            Log(nameof(GetNextStateRootHash));
-            return _store.GetNextStateRootHash(blockHash);
-        }
-
-        public void PutNextStateRootHash(BlockHash blockHash, HashDigest<SHA256> nextStateRootHash)
-        {
-            Log(nameof(PutNextStateRootHash));
-            _store.PutNextStateRootHash(blockHash, nextStateRootHash);
-        }
-
-        public void DeleteNextStateRootHash(BlockHash blockHash)
-        {
-            Log(nameof(DeleteNextStateRootHash));
-            _store.DeleteNextStateRootHash(blockHash);
-        }
-
         public Guid? GetCanonicalChainId()
         {
             Log(nameof(GetCanonicalChainId));
diff --git a/Libplanet/Blockchain/BlockChain.Next.cs b/Libplanet/Blockchain/BlockChain.Next.cs
new file mode 100644
index 00000000000..e12c70d6c12
--- /dev/null
+++ b/Libplanet/Blockchain/BlockChain.Next.cs
@@ -0,0 +1,12 @@
+using System.Security.Cryptography;
+using Libplanet.Common;
+
+namespace Libplanet.Blockchain
+{
+    public partial class BlockChain
+    {
+        private HashDigest<SHA256>? _nextStateRootHash;
+
+        public HashDigest<SHA256>? NextStateRootHash => _nextStateRootHash;
+    }
+}
diff --git a/Libplanet/Blockchain/BlockChain.States.cs b/Libplanet/Blockchain/BlockChain.States.cs
index c0725cca2f4..56738617d13 100644
--- a/Libplanet/Blockchain/BlockChain.States.cs
+++ b/Libplanet/Blockchain/BlockChain.States.cs
@@ -28,12 +28,11 @@ public IWorldState GetWorldState(HashDigest<SHA256>? stateRootHash)
         /// <returns>The next world state.  If it does not exist, returns null.</returns>
         public IWorldState? GetNextWorldState()
         {
-            var nextSrh = GetNextStateRootHash();
-            if (nextSrh is { } srh)
+            if (GetNextStateRootHash() is { } srh)
             {
                 var trie = StateStore.GetStateRoot(srh);
                 return trie.Recorded
-                    ? new WorldBaseState(StateStore.GetStateRoot(nextSrh), StateStore)
+                    ? new WorldBaseState(trie, StateStore)
                     : throw new InvalidOperationException(
                         $"Could not find state root {srh} in {nameof(StateStore)} for " +
                         $"the current tip.");
diff --git a/Libplanet/Blockchain/BlockChain.Swap.cs b/Libplanet/Blockchain/BlockChain.Swap.cs
index 0643a519044..c6783b05bc2 100644
--- a/Libplanet/Blockchain/BlockChain.Swap.cs
+++ b/Libplanet/Blockchain/BlockChain.Swap.cs
@@ -109,6 +109,7 @@ HashSet<TxId> GetTxIdsWithRange(
                     TipChanged?.Invoke(this, (oldTip, newTip));
 
                     Store.DeleteChainId(obsoleteId);
+                    _nextStateRootHash = other.NextStateRootHash;
                 }
                 finally
                 {
diff --git a/Libplanet/Blockchain/BlockChain.cs b/Libplanet/Blockchain/BlockChain.cs
index c99f5fad400..e0d336ccf09 100644
--- a/Libplanet/Blockchain/BlockChain.cs
+++ b/Libplanet/Blockchain/BlockChain.cs
@@ -185,15 +185,13 @@ private BlockChain(
 
             if (Tip.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
             {
-                Store.PutNextStateRootHash(Tip.Hash, Tip.StateRootHash);
+                _nextStateRootHash = Tip.StateRootHash;
             }
             else
             {
                 HashDigest<SHA256> nextStateRootHash =
                     DetermineNextBlockStateRootHash(Tip, out var actionEvaluations);
-
-                Store.DeleteNextStateRootHash(Tip.Hash);
-                Store.PutNextStateRootHash(Tip.Hash, nextStateRootHash);
+                _nextStateRootHash = nextStateRootHash;
 
                 IEnumerable<TxExecution> txExecutions = MakeTxExecutions(Tip, actionEvaluations);
                 UpdateTxExecutions(txExecutions);
@@ -758,23 +756,13 @@ public BlockChain Fork(BlockHash point, bool inheritRenderers = true)
                 _rwlock.EnterReadLock();
 
                 Store.AppendIndex(forkedId, Genesis.Hash);
-                var forked = new BlockChain(
-                    Policy,
-                    StagePolicy,
-                    Store,
-                    StateStore,
-                    forkedId,
-                    Genesis,
-                    _blockChainStates,
-                    ActionEvaluator,
-                    renderers);
                 Store.ForkBlockIndexes(Id, forkedId, point);
                 if (GetBlockCommit(point) is { } p)
                 {
                     Store.PutChainBlockCommit(forkedId, GetBlockCommit(point));
                 }
 
-                Store.ForkTxNonces(Id, forked.Id);
+                Store.ForkTxNonces(Id, forkedId);
                 for (Block block = Tip;
                      block.PreviousHash is { } hash && !block.Hash.Equals(point);
                      block = _blocks[hash])
@@ -786,10 +774,21 @@ public BlockChain Fork(BlockHash point, bool inheritRenderers = true)
 
                     foreach ((Address address, int txCount) in signers)
                     {
-                        Store.IncreaseTxNonce(forked.Id, address, -txCount);
+                        Store.IncreaseTxNonce(forkedId, address, -txCount);
                     }
                 }
 
+                var forked = new BlockChain(
+                    Policy,
+                    StagePolicy,
+                    Store,
+                    StateStore,
+                    forkedId,
+                    Genesis,
+                    _blockChainStates,
+                    ActionEvaluator,
+                    renderers);
+
                 _logger.Information(
                     "Forked chain at #{Index} {Hash} from id {PreviousId} to id {ForkedId}",
                     pointBlock.Index,
@@ -985,6 +984,7 @@ internal void Append(
                     }
 
                     Store.AppendIndex(Id, block.Hash);
+                    _nextStateRootHash = null;
                 }
                 finally
                 {
@@ -1027,8 +1027,7 @@ internal void Append(
 
                 HashDigest<SHA256> nextStateRootHash =
                     DetermineNextBlockStateRootHash(block, out var actionEvaluations);
-
-                Store.PutNextStateRootHash(block.Hash, nextStateRootHash);
+                _nextStateRootHash = nextStateRootHash;
 
                 IEnumerable<TxExecution> txExecutions =
                     MakeTxExecutions(block, actionEvaluations);
@@ -1160,10 +1159,6 @@ internal void AppendStateRootHashPreceded(
                                 TimestampFormat, CultureInfo.InvariantCulture));
 
                     _blocks[block.Hash] = block;
-                    Store.PutNextStateRootHash(block.Hash, block.StateRootHash);
-                    IEnumerable<TxExecution> txExecutions =
-                        MakeTxExecutions(block, actionEvaluations);
-                    UpdateTxExecutions(txExecutions);
 
                     foreach (KeyValuePair<Address, long> pair in nonceDeltas)
                     {
@@ -1181,6 +1176,10 @@ internal void AppendStateRootHashPreceded(
                     }
 
                     Store.AppendIndex(Id, block.Hash);
+                    _nextStateRootHash = block.StateRootHash;
+                    IEnumerable<TxExecution> txExecutions =
+                        MakeTxExecutions(block, actionEvaluations);
+                    UpdateTxExecutions(txExecutions);
                 }
                 finally
                 {
@@ -1405,8 +1404,7 @@ internal void CleanupBlockCommitStore(long limit)
             }
         }
 
-        internal HashDigest<SHA256>? GetNextStateRootHash() =>
-            GetNextStateRootHash(Tip);
+        internal HashDigest<SHA256>? GetNextStateRootHash() => NextStateRootHash;
 
         internal HashDigest<SHA256>? GetNextStateRootHash(long index) =>
             GetNextStateRootHash(this[index]);
@@ -1424,8 +1422,10 @@ internal void CleanupBlockCommitStore(long limit)
             {
                 return this[block.Index + 1].StateRootHash;
             }
-
-            return Store.GetNextStateRootHash(block.Hash);
+            else
+            {
+                return GetNextStateRootHash();
+            }
         }
     }
 }

From 9fb3413e16e2b41fcb978459865f02311f6f4a40 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 20 Jun 2024 16:51:54 +0900
Subject: [PATCH 07/11] Cleanup

---
 Libplanet/Blockchain/BlockChain.Next.cs | 12 ------------
 Libplanet/Blockchain/BlockChain.Swap.cs |  2 +-
 Libplanet/Blockchain/BlockChain.cs      |  4 +++-
 3 files changed, 4 insertions(+), 14 deletions(-)
 delete mode 100644 Libplanet/Blockchain/BlockChain.Next.cs

diff --git a/Libplanet/Blockchain/BlockChain.Next.cs b/Libplanet/Blockchain/BlockChain.Next.cs
deleted file mode 100644
index e12c70d6c12..00000000000
--- a/Libplanet/Blockchain/BlockChain.Next.cs
+++ /dev/null
@@ -1,12 +0,0 @@
-using System.Security.Cryptography;
-using Libplanet.Common;
-
-namespace Libplanet.Blockchain
-{
-    public partial class BlockChain
-    {
-        private HashDigest<SHA256>? _nextStateRootHash;
-
-        public HashDigest<SHA256>? NextStateRootHash => _nextStateRootHash;
-    }
-}
diff --git a/Libplanet/Blockchain/BlockChain.Swap.cs b/Libplanet/Blockchain/BlockChain.Swap.cs
index c6783b05bc2..ca35491bb9f 100644
--- a/Libplanet/Blockchain/BlockChain.Swap.cs
+++ b/Libplanet/Blockchain/BlockChain.Swap.cs
@@ -109,7 +109,7 @@ HashSet<TxId> GetTxIdsWithRange(
                     TipChanged?.Invoke(this, (oldTip, newTip));
 
                     Store.DeleteChainId(obsoleteId);
-                    _nextStateRootHash = other.NextStateRootHash;
+                    _nextStateRootHash = other._nextStateRootHash;
                 }
                 finally
                 {
diff --git a/Libplanet/Blockchain/BlockChain.cs b/Libplanet/Blockchain/BlockChain.cs
index e0d336ccf09..56b1c782cb9 100644
--- a/Libplanet/Blockchain/BlockChain.cs
+++ b/Libplanet/Blockchain/BlockChain.cs
@@ -64,6 +64,8 @@ public partial class BlockChain : IBlockChainStates
         /// </summary>
         private Block _genesis;
 
+        private HashDigest<SHA256>? _nextStateRootHash;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="BlockChain"/> class by loading
         /// the canonical chain from given <paramref name="store"/>.
@@ -1404,7 +1406,7 @@ internal void CleanupBlockCommitStore(long limit)
             }
         }
 
-        internal HashDigest<SHA256>? GetNextStateRootHash() => NextStateRootHash;
+        internal HashDigest<SHA256>? GetNextStateRootHash() => _nextStateRootHash;
 
         internal HashDigest<SHA256>? GetNextStateRootHash(long index) =>
             GetNextStateRootHash(this[index]);

From d1a0544711487948a256deb333db843418f5fb25 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 20 Jun 2024 18:19:09 +0900
Subject: [PATCH 08/11] Cleanup unnecessary code

---
 Libplanet.Net/Consensus/ConsensusContext.cs |  3 +-
 Libplanet.Tests/Action/WorldTest.cs         |  4 +-
 Libplanet.Tests/TestUtils.cs                |  6 +-
 Libplanet/Blockchain/BlockChain.Evaluate.cs | 66 +++++++++------------
 Libplanet/Blockchain/BlockChain.Validate.cs |  8 +--
 Libplanet/Blockchain/BlockChain.cs          | 14 ++---
 6 files changed, 42 insertions(+), 59 deletions(-)

diff --git a/Libplanet.Net/Consensus/ConsensusContext.cs b/Libplanet.Net/Consensus/ConsensusContext.cs
index f695fd365ba..762c0bae8e6 100644
--- a/Libplanet.Net/Consensus/ConsensusContext.cs
+++ b/Libplanet.Net/Consensus/ConsensusContext.cs
@@ -452,8 +452,7 @@ private Context CreateContext(long height)
         {
             // blockchain may not contain block of Height - 1?
             ValidatorSet validatorSet;
-            if (_blockChain.Tip.ProtocolVersion
-                < BlockMetadata.SlothProtocolVersion)
+            if (_blockChain.Tip.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
             {
                 validatorSet = _blockChain
                     .GetWorldState(_blockChain[Height - 1].StateRootHash)
diff --git a/Libplanet.Tests/Action/WorldTest.cs b/Libplanet.Tests/Action/WorldTest.cs
index 1598fcb52d0..27f1210d9e1 100644
--- a/Libplanet.Tests/Action/WorldTest.cs
+++ b/Libplanet.Tests/Action/WorldTest.cs
@@ -505,9 +505,7 @@ public virtual void TotalSupplyTracking()
         }
 
         protected static IWorldState GetLatestWorldState(BlockChain blockChain) =>
-            blockChain.Tip.ProtocolVersion < BlockMetadata.SlothProtocolVersion
-                ? blockChain.GetWorldState()
-                : blockChain.GetNextWorldState();
+            blockChain.GetNextWorldState();
 
         protected FungibleAssetValue Value(int currencyIndex, BigInteger quantity) =>
             new FungibleAssetValue(_currencies[currencyIndex], quantity, 0);
diff --git a/Libplanet.Tests/TestUtils.cs b/Libplanet.Tests/TestUtils.cs
index 933f9476d2e..2f8186d85df 100644
--- a/Libplanet.Tests/TestUtils.cs
+++ b/Libplanet.Tests/TestUtils.cs
@@ -626,7 +626,7 @@ public static (BlockChain BlockChain, ActionEvaluator ActionEvaluator)
                     timestamp,
                     protocolVersion);
                 var evaluatedSrh = actionEvaluator.Evaluate(preEval, null).Last().OutputState;
-                genesisBlock = protocolVersion < 2
+                genesisBlock = protocolVersion < BlockMetadata.SignatureProtocolVersion
                     ? new Block(
                         preEval,
                         (
@@ -635,8 +635,8 @@ public static (BlockChain BlockChain, ActionEvaluator ActionEvaluator)
                             preEval.Header.DeriveBlockHash(evaluatedSrh, null)
                         ))
                     : protocolVersion < BlockMetadata.SlothProtocolVersion
-                    ? preEval.Sign(GenesisProposer, evaluatedSrh)
-                    : preEval.Sign(GenesisProposer, MerkleTrie.EmptyRootHash);
+                        ? preEval.Sign(GenesisProposer, evaluatedSrh)
+                        : preEval.Sign(GenesisProposer, MerkleTrie.EmptyRootHash);
             }
 
             ValidatingActionRenderer validator = null;
diff --git a/Libplanet/Blockchain/BlockChain.Evaluate.cs b/Libplanet/Blockchain/BlockChain.Evaluate.cs
index 7dc56aea34a..3abb563cc6c 100644
--- a/Libplanet/Blockchain/BlockChain.Evaluate.cs
+++ b/Libplanet/Blockchain/BlockChain.Evaluate.cs
@@ -113,48 +113,38 @@ public IReadOnlyList<ICommittedActionEvaluation> EvaluateBlock(Block block) =>
         internal Block EvaluateAndSign(
             PreEvaluationBlock preEvaluationBlock, PrivateKey privateKey)
         {
-            if (preEvaluationBlock.Index < 1)
+            if (preEvaluationBlock.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
             {
-                throw new ArgumentException(
-                    $"Given {nameof(preEvaluationBlock)} must have block index " +
-                    $"higher than 0");
-            }
-
-            if (preEvaluationBlock.ProtocolVersion < BlockMetadata.SignatureProtocolVersion)
-            {
-                throw new ArgumentException(
-                    $"Given {nameof(preEvaluationBlock)} must have protocol version " +
-                    $"2 or greater: {preEvaluationBlock.ProtocolVersion}");
-            }
-
-            if (preEvaluationBlock.ProtocolVersion <
-                BlockMetadata.SlothProtocolVersion)
-            {
-                return preEvaluationBlock.Sign(
-                    privateKey,
-                    DetermineBlockPrecededStateRootHash(preEvaluationBlock, out _));
-            }
-
-            if (!(preEvaluationBlock.PreviousHash is BlockHash previousHash))
-            {
-                throw new ArgumentException(
-                    $"Given {nameof(preEvaluationBlock)} must have non-null previous hash " +
-                    $"If it isn't genesis");
-            }
-
-            if (_blocks[previousHash].ProtocolVersion
-                < BlockMetadata.SlothProtocolVersion)
-            {
-                return preEvaluationBlock.Sign(privateKey, _blocks[previousHash].StateRootHash);
+                if (preEvaluationBlock.ProtocolVersion < BlockMetadata.SignatureProtocolVersion)
+                {
+                    throw new ArgumentException(
+                        $"Given {nameof(preEvaluationBlock)} must have protocol version " +
+                        $"2 or greater: {preEvaluationBlock.ProtocolVersion}");
+                }
+                else
+                {
+                    return preEvaluationBlock.Sign(
+                        privateKey,
+                        DetermineBlockPrecededStateRootHash(preEvaluationBlock, out _));
+                }
             }
-
-            if (!(GetNextStateRootHash(previousHash) is HashDigest<SHA256> stateRootHash))
+            else
             {
-                throw new NullReferenceException(
-                    $"State root hash of block is not prepared");
+                if (preEvaluationBlock.Index < 1)
+                {
+                    throw new ArgumentException(
+                        $"Given {nameof(preEvaluationBlock)} must have block index " +
+                        $"higher than 0");
+                }
+                else
+                {
+                    var prevBlock = _blocks[(BlockHash)preEvaluationBlock.PreviousHash];
+                    var stateRootHash = GetNextStateRootHash(prevBlock.Hash)
+                        ?? throw new NullReferenceException(
+                            $"State root hash of block is not prepared");
+                    return preEvaluationBlock.Sign(privateKey, stateRootHash);
+                }
             }
-
-            return preEvaluationBlock.Sign(privateKey, stateRootHash);
         }
 
         /// <summary>
diff --git a/Libplanet/Blockchain/BlockChain.Validate.cs b/Libplanet/Blockchain/BlockChain.Validate.cs
index a66adfaaffb..eb3d1dc6e87 100644
--- a/Libplanet/Blockchain/BlockChain.Validate.cs
+++ b/Libplanet/Blockchain/BlockChain.Validate.cs
@@ -140,11 +140,9 @@ internal void ValidateBlockCommit(
 
             // FIXME: When the dynamic validator set is possible, the functionality of this
             // condition should be checked once more.
-            var validators =
-                block.ProtocolVersion <
-                BlockMetadata.SlothProtocolVersion
-                    ? GetWorldState(block.PreviousHash ?? Genesis.Hash).GetValidatorSet()
-                    : GetWorldState(block.StateRootHash).GetValidatorSet();
+            var validators = block.ProtocolVersion < BlockMetadata.SlothProtocolVersion
+                ? GetWorldState(block.PreviousHash ?? Genesis.Hash).GetValidatorSet()
+                : GetWorldState(block.StateRootHash).GetValidatorSet();
             if (!validators.ValidateBlockCommitValidators(blockCommit))
             {
                 throw new InvalidBlockCommitException(
diff --git a/Libplanet/Blockchain/BlockChain.cs b/Libplanet/Blockchain/BlockChain.cs
index 56b1c782cb9..50b69331eba 100644
--- a/Libplanet/Blockchain/BlockChain.cs
+++ b/Libplanet/Blockchain/BlockChain.cs
@@ -191,10 +191,8 @@ private BlockChain(
             }
             else
             {
-                HashDigest<SHA256> nextStateRootHash =
+                _nextStateRootHash =
                     DetermineNextBlockStateRootHash(Tip, out var actionEvaluations);
-                _nextStateRootHash = nextStateRootHash;
-
                 IEnumerable<TxExecution> txExecutions = MakeTxExecutions(Tip, actionEvaluations);
                 UpdateTxExecutions(txExecutions);
             }
@@ -391,8 +389,7 @@ public static BlockChain Create(
 
             var id = Guid.NewGuid();
 
-            if (genesisBlock.ProtocolVersion <
-                BlockMetadata.SlothProtocolVersion)
+            if (genesisBlock.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
             {
                 var preEval = new PreEvaluationBlock(
                     genesisBlock.Header, genesisBlock.Transactions);
@@ -546,10 +543,11 @@ public void Append(
             if (block.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
             {
                 AppendStateRootHashPreceded(block, blockCommit, render: true);
-                return;
             }
-
-            Append(block, blockCommit, render: true);
+            else
+            {
+                Append(block, blockCommit, render: true);
+            }
         }
 
         /// <summary>

From 9952b6db2641d7f749261ad53b988bd17b1e98c4 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 20 Jun 2024 19:00:17 +0900
Subject: [PATCH 09/11] Renamed extension methods

---
 Libplanet.Net.Tests/Consensus/ContextTest.cs  |  4 +-
 Libplanet.Net.Tests/TestUtils.cs              |  2 +-
 Libplanet.Tests/BlockChainExtensions.cs       | 44 +++++--------------
 .../Blockchain/BlockChainTest.Append.cs       |  4 +-
 Libplanet.Tests/Blockchain/BlockChainTest.cs  |  4 +-
 5 files changed, 19 insertions(+), 39 deletions(-)

diff --git a/Libplanet.Net.Tests/Consensus/ContextTest.cs b/Libplanet.Net.Tests/Consensus/ContextTest.cs
index a3a464ef807..caeca6a5f59 100644
--- a/Libplanet.Net.Tests/Consensus/ContextTest.cs
+++ b/Libplanet.Net.Tests/Consensus/ContextTest.cs
@@ -323,7 +323,7 @@ void BroadcastMessage(ConsensusMsg message) =>
                 1L,
                 TestUtils.PrivateKeys[0],
                 blockChain
-                    .GetResultWorldState(0)
+                    .GetNextWorldState(0)
                     .GetValidatorSet(),
                 contextTimeoutOptions: new ContextTimeoutOption());
 
@@ -625,7 +625,7 @@ void BroadcastMessage(ConsensusMsg message) =>
                 1L,
                 TestUtils.PrivateKeys[0],
                 blockChain
-                    .GetResultWorldState(0L)
+                    .GetNextWorldState(0L)
                     .GetValidatorSet(),
                 contextTimeoutOptions: new ContextTimeoutOption());
 
diff --git a/Libplanet.Net.Tests/TestUtils.cs b/Libplanet.Net.Tests/TestUtils.cs
index a83c00fea82..1c72f6f1fb9 100644
--- a/Libplanet.Net.Tests/TestUtils.cs
+++ b/Libplanet.Net.Tests/TestUtils.cs
@@ -289,7 +289,7 @@ void BroadcastMessage(ConsensusMsg message) =>
                 height,
                 privateKey,
                 validatorSet ?? blockChain
-                    .GetResultWorldState(height - 1)
+                    .GetNextWorldState(height - 1)
                     .GetValidatorSet(),
                 contextTimeoutOptions: contextTimeoutOptions ?? new ContextTimeoutOption());
 
diff --git a/Libplanet.Tests/BlockChainExtensions.cs b/Libplanet.Tests/BlockChainExtensions.cs
index da010032987..a434832f9c6 100644
--- a/Libplanet.Tests/BlockChainExtensions.cs
+++ b/Libplanet.Tests/BlockChainExtensions.cs
@@ -8,9 +8,6 @@ namespace Libplanet.Tests
 {
     public static class BlockChainExtensions
     {
-        public static Block GetNextBlock(this BlockChain blockChain, BlockHash blockHash) =>
-            blockChain[blockChain[blockHash].Index + 1];
-
         /// <summary>
         /// Returns an <see cref="IWorldState"/> resulting from the execution of
         /// the tip of <paramref name="blockChain"/>.
@@ -18,8 +15,10 @@ public static Block GetNextBlock(this BlockChain blockChain, BlockHash blockHash
         /// <param name="blockChain">The <see cref="BlockChain"/> to search.</param>
         /// <returns>An <see cref="IWorldState"/> resulting from the execution of
         /// the tip of <paramref name="blockChain"/>.</returns>
-        public static IWorldState GetResultWorldState(this BlockChain blockChain) =>
-            GetResultWorldState(blockChain, blockChain.Tip);
+        public static IWorldState GetNextWorldState(this BlockChain blockChain) =>
+            blockChain.GetNextStateRootHash() is HashDigest<SHA256> stateRootHash
+                ? blockChain.GetWorldState(stateRootHash)
+                : null;
 
         /// <summary>
         /// Returns an <see cref="IWorldState"/> resulting from the execution of
@@ -30,8 +29,10 @@ public static IWorldState GetResultWorldState(this BlockChain blockChain) =>
         /// <param name="index">The index of a <see cref="Block"/> to search.</param>
         /// <returns>An <see cref="IWorldState"/> resulting from the execution of
         /// a <see cref="Block"/> associated with given <paramref name="index"/>.</returns>
-        public static IWorldState GetResultWorldState(this BlockChain blockChain, long index) =>
-            GetResultWorldState(blockChain, blockChain[index]);
+        public static IWorldState GetNextWorldState(this BlockChain blockChain, long index) =>
+            blockChain.GetNextStateRootHash(index) is HashDigest<SHA256> stateRootHash
+                ? blockChain.GetWorldState(stateRootHash)
+                : null;
 
         /// <summary>
         /// Returns an <see cref="IWorldState"/> resulting from the execution of
@@ -42,32 +43,11 @@ public static IWorldState GetResultWorldState(this BlockChain blockChain, long i
         /// <param name="blockHash">The <see cref="BlockHash"/> to search.</param>
         /// <returns>An <see cref="IWorldState"/> resulting from the execution of
         /// a <see cref="Block"/> associated with given <paramref name="blockHash"/>.</returns>
-        public static IWorldState GetResultWorldState(
+        public static IWorldState GetNextWorldState(
             this BlockChain blockChain,
             BlockHash blockHash) =>
-            GetResultWorldState(blockChain, blockChain[blockHash]);
-
-        private static IWorldState GetResultWorldState(BlockChain blockChain, Block block)
-        {
-            if (block.ProtocolVersion < BlockMetadata.SlothProtocolVersion)
-            {
-                return blockChain.GetWorldState(block.StateRootHash);
-            }
-            else
-            {
-                // Since block is fetched from blockChain, its index will be at most tip's index.
-                if (block.Index < blockChain.Tip.Index)
-                {
-                    return blockChain.GetWorldState(blockChain[block.Index + 1].StateRootHash);
-                }
-                else
-                {
-                    return blockChain.GetNextStateRootHash(block.Hash) is
-                        HashDigest<SHA256> stateRootHash
-                            ? blockChain.GetWorldState(stateRootHash)
-                            : null;
-                }
-            }
-        }
+            blockChain.GetNextStateRootHash(blockHash) is HashDigest<SHA256> stateRootHash
+                ? blockChain.GetWorldState(stateRootHash)
+                : null;
     }
 }
diff --git a/Libplanet.Tests/Blockchain/BlockChainTest.Append.cs b/Libplanet.Tests/Blockchain/BlockChainTest.Append.cs
index a731556927d..333ac0b00e6 100644
--- a/Libplanet.Tests/Blockchain/BlockChainTest.Append.cs
+++ b/Libplanet.Tests/Blockchain/BlockChainTest.Append.cs
@@ -786,10 +786,10 @@ public void DoesNotMigrateStateWithoutAction()
                 ImmutableList<Transaction>.Empty,
                 TestUtils.CreateBlockCommit(blockChain.Tip));
             blockChain.Append(emptyBlock, TestUtils.CreateBlockCommit(emptyBlock));
-            Assert.True(blockChain.GetResultWorldState(emptyBlock.Hash).Legacy);
+            Assert.True(blockChain.GetNextWorldState(emptyBlock.Hash).Legacy);
             Assert.Equal<byte>(
                 blockChain.GetWorldState(genesis.StateRootHash).Trie.Hash.ByteArray,
-                blockChain.GetResultWorldState(emptyBlock.Hash).Trie.Hash.ByteArray);
+                blockChain.GetNextWorldState(emptyBlock.Hash).Trie.Hash.ByteArray);
         }
 
         [Fact]
diff --git a/Libplanet.Tests/Blockchain/BlockChainTest.cs b/Libplanet.Tests/Blockchain/BlockChainTest.cs
index 4c6561c9b9c..ebe3079bb93 100644
--- a/Libplanet.Tests/Blockchain/BlockChainTest.cs
+++ b/Libplanet.Tests/Blockchain/BlockChainTest.cs
@@ -2314,7 +2314,7 @@ private void ValidateNextBlockCommitOnValidatorSetChange()
 
             Assert.Equal(
                 blockChain
-                    .GetResultWorldState(0)
+                    .GetNextWorldState(0)
                     .GetValidatorSet(),
                 new ValidatorSet(
                     ValidatorPrivateKeys.Select(
@@ -2322,7 +2322,7 @@ private void ValidateNextBlockCommitOnValidatorSetChange()
 
             Assert.Equal(
                 blockChain
-                    .GetResultWorldState(1)
+                    .GetNextWorldState(1)
                     .GetValidatorSet(),
                 new ValidatorSet(
                     newValidators.Select(

From 0b86001f0d4d003d0eab7542b5ea5b680557305f Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 20 Jun 2024 19:32:12 +0900
Subject: [PATCH 10/11] Changelog

---
 CHANGES.md                                  | 10 ----------
 Libplanet.Action/State/IBlockChainStates.cs |  6 +++---
 2 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index b388556b429..780857939bd 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -28,8 +28,6 @@ To be released.
     parameter `IActionEvaluator actionEvaluator` any more.  [[#3811]]
  -  (Libplanet) `BlockChain.ProposeBlock()` receives parameter
     `HashDigest<SHA256> stateRootHash`.  [[#3811]]
- -  (Libplanet) Added `BlockChain.GetNextWorldState()` and
-    `BlockChain.GetNextWorldState(BlockHash?)` methods.  [[#3821]]
 
 ### Backward-incompatible network protocol changes
 
@@ -37,12 +35,6 @@ To be released.
 
 ### Added APIs
 
- -  (Libplanet.Store) Added `IStore.GetNextStateRootHash()` method.
-    [[#3811]]
- -  (Libplanet.Store) Added `IStore.PutNextStateRootHash()` method.
-    [[#3811]]
- -  (Libplanet.Store) Added `IStore.DeleteNextStateRootHash()` method.
-    [[#3811]]
  -  (Libplanet) Added `BlockChain.DetermineNextBlockStateRootHash()`
     method.  [[#3811]]
 
@@ -51,8 +43,6 @@ To be released.
  -  `BlockHeader.StateRootHash` now means state root hash calculated by
     `BlockChain.DetermineNextBlockStateRootHash(previousBlockHash)`.
     [[#Sloth]]
- -  `IBlockChainStates.GetWorldState(BlockHash)` now means the `IWorldState`
-    before state transition from the `Block`.  [[#3811]]
  -  `Context.ProcessHeightOrRoundUponRules()` now appends block asynchronously,
     as a manner of fire-and-forget.  [[#3808]]
 
diff --git a/Libplanet.Action/State/IBlockChainStates.cs b/Libplanet.Action/State/IBlockChainStates.cs
index 005c32eee3c..f7dbdd62929 100644
--- a/Libplanet.Action/State/IBlockChainStates.cs
+++ b/Libplanet.Action/State/IBlockChainStates.cs
@@ -22,8 +22,8 @@ public interface IBlockChainStates
         /// The <see cref="IWorldState"/> at <paramref name="offset"/>, which is the identical
         /// to what <see cref="Block.StateRootHash"/> of <paramref name="offset"/> indicates.
         /// </returns>
-        /// <exception cref="ArgumentException">Thrown when <paramref name="offset"/>
-        /// one of the following is true.
+        /// <exception cref="ArgumentException">Thrown when one of the following is true
+        /// for <paramref name="offset"/>.
         /// <list type="bullet">
         ///     <item><description>
         ///         Corresponding <see cref="Block"/> is not found in the <see cref="IStore"/>.
@@ -46,7 +46,7 @@ public interface IBlockChainStates
         /// <returns>
         /// The <see cref="IWorldState"/> with <paramref name="stateRootHash"/>.
         /// If <paramref name="stateRootHash"/> is <see langword="null"/>,
-        /// returns the hash of the empty state root.
+        /// returns an empty <see cref="IWorldState"/>.
         /// </returns>
         /// <exception cref="ArgumentException">Thrown when no <see cref="ITrie"/> with
         /// <paramref name="hash"/> as its state root hash is found.

From 48e13a97d9b16330c40f07f67aa2eb9003a8d0af Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Fri, 21 Jun 2024 11:09:27 +0900
Subject: [PATCH 11/11] Added suggested changes

Co-authored-by: ilgyu <ilgyu@planetariumhq.com>
---
 Libplanet.Net.Tests/Consensus/ContextTest.cs |  2 +-
 Libplanet.Tests/Action/WorldTest.cs          | 15 ++++++++-------
 Libplanet.Tests/Blockchain/BlockChainTest.cs |  4 ++--
 Libplanet/Blockchain/BlockChain.States.cs    |  6 +++---
 4 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/Libplanet.Net.Tests/Consensus/ContextTest.cs b/Libplanet.Net.Tests/Consensus/ContextTest.cs
index caeca6a5f59..61e7cb78c36 100644
--- a/Libplanet.Net.Tests/Consensus/ContextTest.cs
+++ b/Libplanet.Net.Tests/Consensus/ContextTest.cs
@@ -323,7 +323,7 @@ void BroadcastMessage(ConsensusMsg message) =>
                 1L,
                 TestUtils.PrivateKeys[0],
                 blockChain
-                    .GetNextWorldState(0)
+                    .GetNextWorldState(0L)
                     .GetValidatorSet(),
                 contextTimeoutOptions: new ContextTimeoutOption());
 
diff --git a/Libplanet.Tests/Action/WorldTest.cs b/Libplanet.Tests/Action/WorldTest.cs
index 27f1210d9e1..a1a58018fb2 100644
--- a/Libplanet.Tests/Action/WorldTest.cs
+++ b/Libplanet.Tests/Action/WorldTest.cs
@@ -260,11 +260,13 @@ public virtual void TransferAssetInBlock()
             chain.Append(block1, TestUtils.CreateBlockCommit(block1));
             Assert.Equal(
                 DumbAction.DumbCurrency * 0,
-                GetLatestWorldState(chain)
+                chain
+                    .GetNextWorldState()
                     .GetBalance(_addr[0], DumbAction.DumbCurrency));
             Assert.Equal(
                 DumbAction.DumbCurrency * 20,
-                GetLatestWorldState(chain)
+                chain
+                    .GetNextWorldState()
                     .GetBalance(_addr[1], DumbAction.DumbCurrency));
 
             // Transfer
@@ -288,11 +290,13 @@ public virtual void TransferAssetInBlock()
             chain.Append(block2, TestUtils.CreateBlockCommit(block2));
             Assert.Equal(
                 DumbAction.DumbCurrency * 5,
-                GetLatestWorldState(chain)
+                chain
+                    .GetNextWorldState()
                     .GetBalance(_addr[0], DumbAction.DumbCurrency));
             Assert.Equal(
                 DumbAction.DumbCurrency * 15,
-                GetLatestWorldState(chain)
+                chain
+                    .GetNextWorldState()
                     .GetBalance(_addr[1], DumbAction.DumbCurrency));
 
             // Transfer bugged
@@ -504,9 +508,6 @@ public virtual void TotalSupplyTracking()
                 world.GetTotalSupply(_currencies[4]));
         }
 
-        protected static IWorldState GetLatestWorldState(BlockChain blockChain) =>
-            blockChain.GetNextWorldState();
-
         protected FungibleAssetValue Value(int currencyIndex, BigInteger quantity) =>
             new FungibleAssetValue(_currencies[currencyIndex], quantity, 0);
     }
diff --git a/Libplanet.Tests/Blockchain/BlockChainTest.cs b/Libplanet.Tests/Blockchain/BlockChainTest.cs
index ebe3079bb93..819eeef1b4d 100644
--- a/Libplanet.Tests/Blockchain/BlockChainTest.cs
+++ b/Libplanet.Tests/Blockchain/BlockChainTest.cs
@@ -2314,7 +2314,7 @@ private void ValidateNextBlockCommitOnValidatorSetChange()
 
             Assert.Equal(
                 blockChain
-                    .GetNextWorldState(0)
+                    .GetNextWorldState(0L)
                     .GetValidatorSet(),
                 new ValidatorSet(
                     ValidatorPrivateKeys.Select(
@@ -2322,7 +2322,7 @@ private void ValidateNextBlockCommitOnValidatorSetChange()
 
             Assert.Equal(
                 blockChain
-                    .GetNextWorldState(1)
+                    .GetNextWorldState(1L)
                     .GetValidatorSet(),
                 new ValidatorSet(
                     newValidators.Select(
diff --git a/Libplanet/Blockchain/BlockChain.States.cs b/Libplanet/Blockchain/BlockChain.States.cs
index 56738617d13..e55a4d35cc1 100644
--- a/Libplanet/Blockchain/BlockChain.States.cs
+++ b/Libplanet/Blockchain/BlockChain.States.cs
@@ -28,13 +28,13 @@ public IWorldState GetWorldState(HashDigest<SHA256>? stateRootHash)
         /// <returns>The next world state.  If it does not exist, returns null.</returns>
         public IWorldState? GetNextWorldState()
         {
-            if (GetNextStateRootHash() is { } srh)
+            if (GetNextStateRootHash() is { } nsrh)
             {
-                var trie = StateStore.GetStateRoot(srh);
+                var trie = StateStore.GetStateRoot(nsrh);
                 return trie.Recorded
                     ? new WorldBaseState(trie, StateStore)
                     : throw new InvalidOperationException(
-                        $"Could not find state root {srh} in {nameof(StateStore)} for " +
+                        $"Could not find state root {nsrh} in {nameof(StateStore)} for " +
                         $"the current tip.");
             }
             else