From 440a173e06c2e7408679e0df64b8a7eeb7c761cd Mon Sep 17 00:00:00 2001
From: Ben Adams <thundercat@illyriad.co.uk>
Date: Mon, 8 Jan 2024 13:35:03 +0000
Subject: [PATCH] Parse BlockParameter correctly for eth_call (#6477)

---
 .../Nethermind.Blockchain/Find/BlockParameter.cs    | 11 ++++++++++-
 .../Modules/Eth/EthRpcModuleTests.EthCall.cs        | 13 +++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/Nethermind/Nethermind.Blockchain/Find/BlockParameter.cs b/src/Nethermind/Nethermind.Blockchain/Find/BlockParameter.cs
index 69bfc03aff4..b646bb29407 100644
--- a/src/Nethermind/Nethermind.Blockchain/Find/BlockParameter.cs
+++ b/src/Nethermind/Nethermind.Blockchain/Find/BlockParameter.cs
@@ -49,6 +49,8 @@ public BlockParameter(long number)
 
         public BlockParameter(Hash256 blockHash, bool requireCanonical = false)
         {
+            ArgumentNullException.ThrowIfNull(blockHash);
+
             Type = BlockParameterType.BlockHash;
             BlockHash = blockHash;
             RequireCanonical = requireCanonical;
@@ -151,10 +153,17 @@ public override void Write(Utf8JsonWriter writer, BlockParameter value, JsonSeri
             if (tokenType == JsonTokenType.StartObject)
             {
                 bool requireCanonical = false;
+                bool readEndObject = false;
                 Hash256 blockHash = null;
                 for (int i = 0; i < 2; i++)
                 {
                     reader.Read();
+                    if (reader.TokenType == JsonTokenType.EndObject)
+                    {
+                        readEndObject = true;
+                        break;
+                    }
+
                     if (reader.ValueTextEquals("requireCanonical"u8))
                     {
                         reader.Read();
@@ -168,7 +177,7 @@ public override void Write(Utf8JsonWriter writer, BlockParameter value, JsonSeri
 
                 BlockParameter parameter = new(blockHash, requireCanonical);
 
-                if (!reader.Read() || reader.TokenType != JsonTokenType.EndObject)
+                if ((!readEndObject && !reader.Read()) || reader.TokenType != JsonTokenType.EndObject)
                 {
                     ThrowInvalidFormatting();
                 }
diff --git a/src/Nethermind/Nethermind.JsonRpc.Test/Modules/Eth/EthRpcModuleTests.EthCall.cs b/src/Nethermind/Nethermind.JsonRpc.Test/Modules/Eth/EthRpcModuleTests.EthCall.cs
index 8773bf7e244..ceb8024cbbb 100644
--- a/src/Nethermind/Nethermind.JsonRpc.Test/Modules/Eth/EthRpcModuleTests.EthCall.cs
+++ b/src/Nethermind/Nethermind.JsonRpc.Test/Modules/Eth/EthRpcModuleTests.EthCall.cs
@@ -137,6 +137,19 @@ public async Task Eth_call_ok()
         Assert.That(serialized, Is.EqualTo("{\"jsonrpc\":\"2.0\",\"result\":\"0x\",\"id\":67}"));
     }
 
+    [Test]
+    public async Task Eth_call_with_blockhash_ok()
+    {
+        using Context ctx = await Context.Create();
+        TransactionForRpc transaction = new(Keccak.Zero, 1L, 1, new Transaction());
+        transaction.From = TestItem.AddressA;
+        transaction.To = TestItem.AddressB;
+
+        string serialized =
+            await ctx.Test.TestEthRpc("eth_call", ctx.Test.JsonSerializer.Serialize(transaction), "{\"blockHash\":\"0xf0b3f69cbd4e1e8d9b0ef02ff5d1384d18e19d251a4052f5f90bab190c5e8937\"}");
+        Assert.That(serialized, Is.EqualTo("{\"jsonrpc\":\"2.0\",\"error\":{\"code\":-32001,\"message\":\"0xf0b3f69cbd4e1e8d9b0ef02ff5d1384d18e19d251a4052f5f90bab190c5e8937 could not be found\"},\"id\":67}"));
+    }
+
     [Test]
     public async Task Eth_call_create_tx_with_empty_data()
     {