XDC Random Value

src/Nethermind/Nethermind.Consensus/Processing/BlockProcessor.cs

@@ -96,6 +96,9 @@ private void ValidateProcessedBlock(Block suggestedBlock, ProcessingOptions opti
     protected bool ShouldComputeStateRoot(BlockHeader header) =>
         !header.IsGenesis || !specProvider.GenesisStateUnavailable;
 
+    protected virtual BlockExecutionContext CreateBlockExecutionContext(BlockHeader header, IReleaseSpec spec) =>
+        new(header, spec);
+
     protected virtual TxReceipt[] ProcessBlock(
         Block block,
         IBlockTracer blockTracer,
@@ -108,7 +111,7 @@ protected virtual TxReceipt[] ProcessBlock(
         ReceiptsTracer.SetOtherTracer(blockTracer);
         ReceiptsTracer.StartNewBlockTrace(block);
 
-        blockTransactionsExecutor.SetBlockExecutionContext(new BlockExecutionContext(block.Header, spec));
+        blockTransactionsExecutor.SetBlockExecutionContext(CreateBlockExecutionContext(block.Header, spec));
 
         StoreBeaconRoot(block, spec);
         blockHashStore.ApplyBlockhashStateChanges(header, spec);

src/Nethermind/Nethermind.Evm/BlockExecutionContext.cs

@@ -10,26 +10,49 @@
 
 namespace Nethermind.Evm;
 
-public readonly struct BlockExecutionContext(BlockHeader blockHeader, IReleaseSpec spec, in UInt256 blobBaseFee)
+public readonly struct BlockExecutionContext
 {
-    public readonly BlockHeader Header = blockHeader;
-    public readonly Address Coinbase = blockHeader.GasBeneficiary ?? Address.Zero;
-    public readonly ulong Number = (ulong)blockHeader.Number;
-    public readonly ulong GasLimit = (ulong)blockHeader.GasLimit;
-    public readonly ValueHash256 BlobBaseFee = blobBaseFee.ToValueHash();
-    public readonly IReleaseSpec Spec = spec;
-
-    // Use the random value if post-merge; otherwise, use block difficulty.
-    public readonly ValueHash256 PrevRandao = blockHeader.IsPostMerge
-        ? (blockHeader.Random ?? Hash256.Zero).ValueHash256
-        : blockHeader.Difficulty.ToValueHash();
+    public readonly BlockHeader Header;
+    public readonly Address Coinbase;
+    public readonly ulong Number;
+    public readonly ulong GasLimit;
+    public readonly ValueHash256 BlobBaseFee;
+    public readonly IReleaseSpec Spec;
+    public readonly ValueHash256 PrevRandao;
+    public readonly bool IsGenesis;
+
+    public BlockExecutionContext(BlockHeader blockHeader, IReleaseSpec spec)
+        : this(blockHeader, spec, GetBlobBaseFee(blockHeader, spec), GetDefaultPrevRandao(blockHeader)) { }
+
+    public BlockExecutionContext(BlockHeader blockHeader, IReleaseSpec spec, in UInt256 blobBaseFee)
+        : this(blockHeader, spec, blobBaseFee, GetDefaultPrevRandao(blockHeader)) { }
 
-    public readonly bool IsGenesis = blockHeader.IsGenesis;
+    public static BlockExecutionContext WithPrevRandao(
+        BlockHeader blockHeader,
+        IReleaseSpec spec,
+        in ValueHash256 prevRandao)
+        => new(blockHeader, spec, GetBlobBaseFee(blockHeader, spec), prevRandao);
 
-    public BlockExecutionContext(BlockHeader blockHeader, IReleaseSpec spec) : this(blockHeader, spec, GetBlobBaseFee(blockHeader, spec))
+    private BlockExecutionContext(
+        BlockHeader blockHeader,
+        IReleaseSpec spec,
+        in UInt256 blobBaseFee,
+        in ValueHash256 prevRandao)
     {
+        Header = blockHeader;
+        Coinbase = blockHeader.GasBeneficiary ?? Address.Zero;
+        Number = (ulong)blockHeader.Number;
+        GasLimit = (ulong)blockHeader.GasLimit;
+        BlobBaseFee = blobBaseFee.ToValueHash();
+        Spec = spec;
+        PrevRandao = prevRandao;
+        IsGenesis = blockHeader.IsGenesis;
     }
 
+    private static ValueHash256 GetDefaultPrevRandao(BlockHeader blockHeader) => blockHeader.IsPostMerge
+        ? (blockHeader.Random ?? Hash256.Zero).ValueHash256
+        : blockHeader.Difficulty.ToValueHash();
+
     private static UInt256 GetBlobBaseFee(BlockHeader? blockHeader, IReleaseSpec spec) =>
         blockHeader?.ExcessBlobGas is not null
             ? !BlobGasCalculator.TryCalculateFeePerBlobGas(blockHeader.ExcessBlobGas.Value, spec.BlobBaseFeeUpdateFraction, out UInt256 feePerBlobGas)

src/Nethermind/Nethermind.Xdc.Test/XdcBlockProcessorTests.cs

@@ -0,0 +1,75 @@
+// SPDX-FileCopyrightText: 2025 Demerzel Solutions Limited
+// SPDX-License-Identifier: LGPL-3.0-only
+
+using FluentAssertions;
+using Nethermind.Blockchain.BeaconBlockRoot;
+using Nethermind.Blockchain.Blocks;
+using Nethermind.Blockchain.Receipts;
+using Nethermind.Consensus.ExecutionRequests;
+using Nethermind.Consensus.Processing;
+using Nethermind.Consensus.Rewards;
+using Nethermind.Consensus.Validators;
+using Nethermind.Consensus.Withdrawals;
+using Nethermind.Core;
+using Nethermind.Core.Crypto;
+using Nethermind.Core.Specs;
+using Nethermind.Core.Test.Builders;
+using Nethermind.Evm;
+using Nethermind.Evm.State;
+using Nethermind.Logging;
+using NSubstitute;
+using NUnit.Framework;
+
+namespace Nethermind.Xdc.Test;
+
+[TestFixture]
+[Parallelizable(ParallelScope.All)]
+internal class XdcBlockProcessorTests
+{
+    private TestableXdcBlockProcessor _processor = null!;
+
+    [SetUp]
+    public void SetUp()
+    {
+        _processor = new TestableXdcBlockProcessor();
+    }
+
+    [
+        TestCase(0L, "0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470"),
+        TestCase(1L, "0x5fe7f977e71dba2ea1a68e21057beebb9be2ac30c6410aa38d4f3fbe41dcffd2"),
+        TestCase(2L, "0xf2ee15ea639b73fa3db9b34a245bdfa015c260c598b211bf05a1ecc4b3e3b4f2"),
+        TestCase(100L, "0xf1918e8562236eb17adc8502332f4c9c82bc14e19bfc0aa10ab674ff75b3d2f3"),
+        TestCase(10_000_000L, "0xcb2bea23225e166d181633a5500bb13f45947baf4699fe7d7be7709662ed2cd4"),
+        TestCase(50_000_000L, "0xcfa4f717b73afc03b1397871f456c85553ea93c536860d57572d2f2b6947e962"),
+        TestCase(999_999_999L, "0xecfe0cf238d62038a8de7039c5c1700a26581c9c3c61e6352085728207948d1f"),
+    ]
+    public void CreateBlockExecutionContext_PrevRandao_MatchesGoXdcRandomValue(long blockNumber, string expectedPrevRandaoHex)
+    {
+        BlockHeader header = Build.A.BlockHeader.WithNumber(blockNumber).TestObject;
+        IReleaseSpec spec = Substitute.For<IReleaseSpec>();
+
+        BlockExecutionContext ctx = _processor.CreateBlockExecutionContext(header, spec);
+
+        ctx.PrevRandao.Should().Be(new ValueHash256(expectedPrevRandaoHex));
+    }
+
+    private class TestableXdcBlockProcessor : XdcBlockProcessor
+    {
+        public TestableXdcBlockProcessor() : base(
+            Substitute.For<ISpecProvider>(),
+            Substitute.For<IBlockValidator>(),
+            Substitute.For<IRewardCalculator>(),
+            Substitute.For<IBlockProcessor.IBlockTransactionsExecutor>(),
+            Substitute.For<IWorldState>(),
+            Substitute.For<IReceiptStorage>(),
+            Substitute.For<IBeaconBlockRootHandler>(),
+            Substitute.For<IBlockhashStore>(),
+            NullLogManager.Instance,
+            Substitute.For<IWithdrawalProcessor>(),
+            Substitute.For<IExecutionRequestsProcessor>())
+        { }
+
+        public new BlockExecutionContext CreateBlockExecutionContext(BlockHeader header, IReleaseSpec spec)
+            => base.CreateBlockExecutionContext(header, spec);
+    }
+}

src/Nethermind/Nethermind.Xdc/XdcBlockProcessor.cs

@@ -10,7 +10,10 @@
 using Nethermind.Consensus.Validators;
 using Nethermind.Consensus.Withdrawals;
 using Nethermind.Core;
+using Nethermind.Core.Crypto;
+using Nethermind.Core.Extensions;
 using Nethermind.Core.Specs;
+using Nethermind.Evm;
 using Nethermind.Evm.State;
 using Nethermind.Logging;
 
@@ -22,6 +25,11 @@ public XdcBlockProcessor(ISpecProvider specProvider, IBlockValidator blockValida
     {
     }
 
+    // Match Go's big.Int.Bytes() behavior: zero produces empty bytes, not [0x00].
+    protected override BlockExecutionContext CreateBlockExecutionContext(BlockHeader header, IReleaseSpec spec) =>
+        BlockExecutionContext.WithPrevRandao(header, spec,
+            ValueKeccak.Compute(header.Number != 0 ? header.Number.ToBigEndianSpanWithoutLeadingZeros(out _) : default));
+
     protected override Block PrepareBlockForProcessing(Block suggestedBlock)
     {
         //TODO find a better way to do this copy