Fix IndexOutOfRangeException on missing or mismatched receipts in BlockValidator

src/Nethermind/Nethermind.Blockchain.Test/Validators/BlockValidatorTests.cs

@@ -202,6 +202,64 @@ public void ValidateProcessedBlock_StateRootIsWrong_ErrorIsSet()
         Assert.That(error, Does.StartWith("InvalidStateRoot"));
     }
 
+    [Test]
+    public void ValidateProcessedBlock_ReceiptCountMismatch_ReturnsFalse()
+    {
+        TxValidator txValidator = new(TestBlockchainIds.ChainId);
+        ISpecProvider specProvider = Substitute.For<ISpecProvider>();
+        BlockValidator sut = new(txValidator, Always.Valid, Always.Valid, specProvider, LimboLogs.Instance);
+        Block suggestedBlock = Build.A.Block.TestObject;
+        Block processedBlock = Build.A.Block
+            .WithStateRoot(Keccak.Zero)
+            .WithTransactions(2, specProvider)
+            .TestObject;
+
+        Assert.That(sut.ValidateProcessedBlock(
+            processedBlock,
+            [],
+            suggestedBlock), Is.False);
+    }
+
+    [Test]
+    public void ValidateProcessedBlock_ReceiptCountMismatch_ErrorIsSet()
+    {
+        TxValidator txValidator = new(TestBlockchainIds.ChainId);
+        ISpecProvider specProvider = Substitute.For<ISpecProvider>();
+        BlockValidator sut = new(txValidator, Always.Valid, Always.Valid, specProvider, LimboLogs.Instance);
+        Block suggestedBlock = Build.A.Block.TestObject;
+        Block processedBlock = Build.A.Block
+            .WithStateRoot(Keccak.Zero)
+            .WithTransactions(3, specProvider)
+            .TestObject;
+
+        sut.ValidateProcessedBlock(
+            processedBlock,
+            [Build.A.Receipt.TestObject],
+            suggestedBlock, out string? error);
+
+        Assert.That(error, Does.StartWith("ReceiptCountMismatch"));
+    }
+
+    [Test]
+    public void ValidateProcessedBlock_EmptyReceiptsWithTransactions_ErrorIsSet()
+    {
+        TxValidator txValidator = new(TestBlockchainIds.ChainId);
+        ISpecProvider specProvider = Substitute.For<ISpecProvider>();
+        BlockValidator sut = new(txValidator, Always.Valid, Always.Valid, specProvider, LimboLogs.Instance);
+        Block suggestedBlock = Build.A.Block.TestObject;
+        Block processedBlock = Build.A.Block
+            .WithStateRoot(Keccak.Zero)
+            .WithTransactions(1, specProvider)
+            .TestObject;
+
+        sut.ValidateProcessedBlock(
+            processedBlock,
+            [],
+            suggestedBlock, out string? error);
+
+        Assert.That(error, Does.StartWith("ReceiptCountMismatch"));
+    }
+
     private static IEnumerable<TestCaseData> BadSuggestedBlocks()
     {
         BlockHeader parent = Build.A.BlockHeader.TestObject;

src/Nethermind/Nethermind.Consensus/Validators/BlockValidator.cs

@@ -164,6 +164,14 @@ public bool ValidateProcessedBlock(Block processedBlock, TxReceipt[] receipts, B
         if (_logger.IsWarn) _logger.Warn($"Processed block {processedBlock.ToString(Block.Format.Short)} is invalid:");
         if (_logger.IsWarn) _logger.Warn($"- hash: expected {suggestedBlock.Hash}, got {processedBlock.Hash}");
         error = null;
+
+        if (receipts.Length != processedBlock.Transactions.Length)
+        {
+            if (_logger.IsWarn) _logger.Warn($"- receipt count mismatch: expected {processedBlock.Transactions.Length} receipts to match transaction count, got {receipts.Length}");
+            error = BlockErrorMessages.ReceiptCountMismatch(processedBlock.Transactions.Length, receipts.Length);
+            return false;
+        }
+
         if (processedBlock.Header.GasUsed != suggestedBlock.Header.GasUsed)
         {
             if (_logger.IsWarn) _logger.Warn($"- gas used: expected {suggestedBlock.Header.GasUsed}, got {processedBlock.Header.GasUsed} (diff: {processedBlock.Header.GasUsed - suggestedBlock.Header.GasUsed})");

src/Nethermind/Nethermind.Core/Messages/BlockErrorMessages.cs

@@ -149,4 +149,7 @@ public static string InvalidDepositEventLayout(string error) =>
 
     public static string ExceededBlockSizeLimit(int limit) =>
         $"ExceededBlockSizeLimit: Exceeded block size limit of {limit} bytes.";
+
+    public static string ReceiptCountMismatch(int expectedCount, int actualCount) =>
+        $"ReceiptCountMismatch: Expected {expectedCount} receipts to match transaction count, but got {actualCount}.";
 }