Properly activate timestamp fork (#6386)

* Activate timestamp fork even if block matches block only fork

* Remove duplication

src/Nethermind/Nethermind.Specs.Test/ChainSpecStyle/ChainSpecBasedSpecProviderTests.cs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: LGPL-3.0-only
 
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -100,15 +101,16 @@ public void Logs_warning_when_timestampActivation_happens_before_blockActivation
         expectedSpec.IsEip3855Enabled = isEip3855Enabled;
         expectedSpec.Eip1559TransitionBlock = 0;
         expectedSpec.DifficultyBombDelay = 0;
-        TestSpecProvider testProvider = TestSpecProvider.Instance;
-        testProvider.SpecToReturn = expectedSpec;
-        testProvider.TerminalTotalDifficulty = 0;
-        testProvider.GenesisSpec = expectedSpec;
         List<ForkActivation> forkActivationsToTest = new()
         {
             (blockNumber, timestamp),
         };
-        CompareSpecProviders(testProvider, provider, forkActivationsToTest);
+
+        foreach (ForkActivation activation in forkActivationsToTest)
+        {
+            provider.GetSpec(activation);
+        }
+
         if (receivesWarning)
         {
             logger.Received(1).Warn(Arg.Is("Chainspec file is misconfigured! Timestamp transition is configured to happen before the last block transition."));
@@ -263,8 +265,8 @@ public void Gnosis_loads_properly()
             (ForkActivation)(GnosisSpecProvider.BerlinBlockNumber),
             (ForkActivation)(GnosisSpecProvider.LondonBlockNumber -1),
             (ForkActivation)(GnosisSpecProvider.LondonBlockNumber),
-            (1, GnosisSpecProvider.ShanghaiTimestamp - 1),
-            (1, GnosisSpecProvider.ShanghaiTimestamp),
+            (GnosisSpecProvider.LondonBlockNumber, GnosisSpecProvider.ShanghaiTimestamp - 1),
+            (GnosisSpecProvider.LondonBlockNumber, GnosisSpecProvider.ShanghaiTimestamp),
             (999_999_999, 999_999_999) // far in the future
         };
 
@@ -804,6 +806,43 @@ void TestTransitions(ForkActivation activation, Action<ReleaseSpec> changes)
         TestTransitions((40001L, 1000000024), r => { r.IsEip1153Enabled = r.IsEip2537Enabled = true; });
     }
 
+    [TestCaseSource(nameof(BlockNumbersAndTimestampsNearForkActivations))]
+    public void Forks_should_be_selected_properly_for_exact_matches(ForkActivation forkActivation, bool isEip3651Enabled, bool isEip3198Enabled, bool isEip3855Enabled)
+    {
+        ISpecProvider provider = new CustomSpecProvider(
+            (new ForkActivation(0), new ReleaseSpec() { IsEip3651Enabled = true }),
+            (new ForkActivation(2, 10), new ReleaseSpec() { IsEip3651Enabled = true, IsEip3198Enabled = true, }),
+            (new ForkActivation(2, 20), new ReleaseSpec() { IsEip3651Enabled = true, IsEip3198Enabled = true, IsEip3855Enabled = true })
+            );
+
+        IReleaseSpec spec = provider.GetSpec(forkActivation);
+        Assert.Multiple(() =>
+        {
+            Assert.That(spec.IsEip3651Enabled, Is.EqualTo(isEip3651Enabled));
+            Assert.That(spec.IsEip3198Enabled, Is.EqualTo(isEip3198Enabled));
+            Assert.That(spec.IsEip3855Enabled, Is.EqualTo(isEip3855Enabled));
+        });
+    }
+
+    public static IEnumerable BlockNumbersAndTimestampsNearForkActivations
+    {
+        get
+        {
+            yield return new TestCaseData(new ForkActivation(1, 9), true, false, false);
+            yield return new TestCaseData(new ForkActivation(2, 9), true, false, false);
+            yield return new TestCaseData(new ForkActivation(2, 10), true, true, false);
+            yield return new TestCaseData(new ForkActivation(2, 11), true, true, false);
+            yield return new TestCaseData(new ForkActivation(2, 19), true, true, false);
+            yield return new TestCaseData(new ForkActivation(2, 20), true, true, true);
+            yield return new TestCaseData(new ForkActivation(2, 21), true, true, true);
+            yield return new TestCaseData(new ForkActivation(3, 10), true, true, false);
+            yield return new TestCaseData(new ForkActivation(3, 11), true, true, false);
+            yield return new TestCaseData(new ForkActivation(3, 19), true, true, false);
+            yield return new TestCaseData(new ForkActivation(3, 20), true, true, true);
+            yield return new TestCaseData(new ForkActivation(3, 21), true, true, true);
+        }
+    }
+
     private static IEnumerable<ulong> GetTransitionTimestamps(ChainParameters parameters) => parameters.GetType()
         .Properties()
         .Where(p => p.Name.EndsWith("TransitionTimestamp", StringComparison.Ordinal))

src/Nethermind/Nethermind.Specs/ChainSpecStyle/ChainSpecBasedSpecProvider.cs

@@ -16,6 +16,7 @@ namespace Nethermind.Specs.ChainSpecStyle
     public class ChainSpecBasedSpecProvider : ISpecProvider
     {
         private (ForkActivation Activation, ReleaseSpec Spec)[] _transitions;
+        private (ForkActivation Activation, ReleaseSpec Spec)[] _timestampOnlyTransitions;
         private ForkActivation? _firstTimestampActivation;
 
         private readonly ChainSpec _chainSpec;
@@ -98,6 +99,7 @@ static void Add(SortedSet<T> transitions, T value, T? minValueExclusive)
             TransitionActivations = CreateTransitionActivations(transitionBlockNumbers, transitionTimestamps);
             _transitions = CreateTransitions(_chainSpec, transitionBlockNumbers, transitionTimestamps);
             _firstTimestampActivation = TransitionActivations.FirstOrDefault(t => t.Timestamp is not null);
+            _timestampOnlyTransitions = _transitions.SkipWhile(t => t.Activation.Timestamp is null).ToArray();
 
             if (_chainSpec.Parameters.TerminalPoWBlockNumber is not null)
             {
@@ -268,6 +270,8 @@ public void UpdateMergeTransitionInfo(long? blockNumber, UInt256? terminalTotalD
 
         public IReleaseSpec GetSpec(ForkActivation activation)
         {
+            (ForkActivation Activation, ReleaseSpec Spec)[] consideredTransitions = _transitions;
+
             // TODO: Is this actually needed? Can this be tricked with invalid activation check if someone would fake timestamp from the future?
             if (_firstTimestampActivation is not null && activation.Timestamp is not null)
             {
@@ -276,9 +280,14 @@ public IReleaseSpec GetSpec(ForkActivation activation)
                 {
                     if (_logger.IsWarn) _logger.Warn($"Chainspec file is misconfigured! Timestamp transition is configured to happen before the last block transition.");
                 }
+
+                if (_firstTimestampActivation.Value.Timestamp <= activation.Timestamp)
+                {
+                    consideredTransitions = _timestampOnlyTransitions;
+                }
             }
 
-            return _transitions.TryGetSearchedItem(activation,
+            return consideredTransitions.TryGetSearchedItem(activation,
                 CompareTransitionOnActivation,
                 out (ForkActivation Activation, ReleaseSpec Spec) transition)
                 ? transition.Spec