Improve MaxNestingDepth of WitnessCondition

src/Neo/Network/P2P/Payloads/Conditions/AndCondition.cs

@@ -61,8 +61,7 @@ public override int GetHashCode()
 
         protected override void DeserializeWithoutType(ref MemoryReader reader, int maxNestDepth)
         {
-            if (maxNestDepth <= 0) throw new FormatException();
-            Expressions = DeserializeConditions(ref reader, maxNestDepth - 1);
+            Expressions = DeserializeConditions(ref reader, maxNestDepth);
             if (Expressions.Length == 0) throw new FormatException();
         }
 
@@ -78,7 +77,6 @@ protected override void SerializeWithoutType(BinaryWriter writer)
 
         private protected override void ParseJson(JObject json, int maxNestDepth)
         {
-            if (maxNestDepth <= 0) throw new FormatException();
             JArray expressions = (JArray)json["expressions"];
             if (expressions.Count > MaxSubitems) throw new FormatException();
             Expressions = expressions.Select(p => FromJson((JObject)p, maxNestDepth - 1)).ToArray();

src/Neo/Network/P2P/Payloads/Conditions/NotCondition.cs

@@ -60,7 +60,6 @@ public override int GetHashCode()
 
         protected override void DeserializeWithoutType(ref MemoryReader reader, int maxNestDepth)
         {
-            if (maxNestDepth <= 0) throw new FormatException();
             Expression = DeserializeFrom(ref reader, maxNestDepth - 1);
         }
 
@@ -76,7 +75,6 @@ protected override void SerializeWithoutType(BinaryWriter writer)
 
         private protected override void ParseJson(JObject json, int maxNestDepth)
         {
-            if (maxNestDepth <= 0) throw new FormatException();
             Expression = FromJson((JObject)json["expression"], maxNestDepth - 1);
         }
 

src/Neo/Network/P2P/Payloads/Conditions/OrCondition.cs

@@ -61,8 +61,7 @@ public override int GetHashCode()
 
         protected override void DeserializeWithoutType(ref MemoryReader reader, int maxNestDepth)
         {
-            if (maxNestDepth <= 0) throw new FormatException();
-            Expressions = DeserializeConditions(ref reader, maxNestDepth - 1);
+            Expressions = DeserializeConditions(ref reader, maxNestDepth);
             if (Expressions.Length == 0) throw new FormatException();
         }
 
@@ -78,7 +77,6 @@ protected override void SerializeWithoutType(BinaryWriter writer)
 
         private protected override void ParseJson(JObject json, int maxNestDepth)
         {
-            if (maxNestDepth <= 0) throw new FormatException();
             JArray expressions = (JArray)json["expressions"];
             if (expressions.Count > MaxSubitems) throw new FormatException();
             Expressions = expressions.Select(p => FromJson((JObject)p, maxNestDepth - 1)).ToArray();

src/Neo/Network/P2P/Payloads/Conditions/WitnessCondition.cs

@@ -25,7 +25,7 @@ namespace Neo.Network.P2P.Payloads.Conditions
     public abstract class WitnessCondition : IInteroperable, ISerializable
     {
         internal const int MaxSubitems = 16;
-        internal const int MaxNestingDepth = 2;
+        internal const int MaxNestingDepth = 3;
 
         /// <summary>
         /// The type of the <see cref="WitnessCondition"/>.
@@ -54,7 +54,7 @@ protected static WitnessCondition[] DeserializeConditions(ref MemoryReader reade
         {
             WitnessCondition[] conditions = new WitnessCondition[reader.ReadVarInt(MaxSubitems)];
             for (int i = 0; i < conditions.Length; i++)
-                conditions[i] = DeserializeFrom(ref reader, maxNestDepth);
+                conditions[i] = DeserializeFrom(ref reader, maxNestDepth - 1);
             return conditions;
         }
 
@@ -66,6 +66,7 @@ protected static WitnessCondition[] DeserializeConditions(ref MemoryReader reade
         /// <returns>The deserialized <see cref="WitnessCondition"/>.</returns>
         public static WitnessCondition DeserializeFrom(ref MemoryReader reader, int maxNestDepth)
         {
+            if (maxNestDepth <= 0) throw new FormatException();
             WitnessConditionType type = (WitnessConditionType)reader.ReadByte();
             if (ReflectionCache<WitnessConditionType>.CreateInstance(type) is not WitnessCondition condition)
                 throw new FormatException();
@@ -109,6 +110,7 @@ void ISerializable.Serialize(BinaryWriter writer)
         /// <returns>The converted <see cref="WitnessCondition"/>.</returns>
         public static WitnessCondition FromJson(JObject json, int maxNestDepth)
         {
+            if (maxNestDepth <= 0) throw new FormatException();
             WitnessConditionType type = Enum.Parse<WitnessConditionType>(json["type"].GetString());
             if (ReflectionCache<WitnessConditionType>.CreateInstance(type) is not WitnessCondition condition)
                 throw new FormatException("Invalid WitnessConditionType.");

tests/Neo.UnitTests/Network/P2P/Payloads/UT_WitnessContition.cs → tests/Neo.UnitTests/Network/P2P/Payloads/UT_WitnessCondition.cs

@@ -1,6 +1,6 @@
 // Copyright (C) 2015-2025 The Neo Project.
 //
-// UT_WitnessContition.cs file belongs to the neo project and is free
+// UT_WitnessCondition.cs file belongs to the neo project and is free
 // software distributed under the MIT software license, see the
 // accompanying file LICENSE in the main directory of the
 // repository or http://www.opensource.org/licenses/mit-license.php
@@ -11,8 +11,11 @@
 
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Neo.Cryptography.ECC;
+using Neo.Extensions;
+using Neo.IO;
 using Neo.Json;
 using Neo.Network.P2P.Payloads.Conditions;
+using System;
 
 namespace Neo.UnitTests.Network.P2P.Payloads
 {
@@ -347,7 +350,7 @@ public void TestFromJson2()
             var hash2 = UInt160.Parse("0xd2a4cff31913016155e38e474a2c06d08be276cf");
             var jstr = "{\"type\":\"Or\",\"expressions\":[{\"type\":\"And\",\"expressions\":[{\"type\":\"CalledByContract\",\"hash\":\"0x0000000000000000000000000000000000000000\"},{\"type\":\"ScriptHash\",\"hash\":\"0xd2a4cff31913016155e38e474a2c06d08be276cf\"}]},{\"type\":\"Or\",\"expressions\":[{\"type\":\"CalledByGroup\",\"group\":\"03b209fd4f53a7170ea4444e0cb0a6bb6a53c2bd016926989cf85f9b0fba17a70c\"},{\"type\":\"Boolean\",\"expression\":true}]}]}";
             var json = (JObject)JToken.Parse(jstr);
-            var condi = WitnessCondition.FromJson(json, 2);
+            var condi = WitnessCondition.FromJson(json, WitnessCondition.MaxNestingDepth);
             var or_condi = (OrCondition)condi;
             Assert.AreEqual(2, or_condi.Expressions.Length);
             var and_condi = (AndCondition)or_condi.Expressions[0];
@@ -363,5 +366,128 @@ public void TestFromJson2()
             Assert.IsTrue(cbgc.Group.Equals(point));
             Assert.IsTrue(bc.Expression);
         }
+
+        [TestMethod]
+        public void Test_WitnessCondition_Nesting()
+        {
+            WitnessCondition nested = new OrCondition
+            {
+                Expressions = [
+                    new OrCondition { Expressions = [new BooleanCondition { Expression = true }] }
+                    ]
+            };
+
+            var buf = nested.ToArray();
+            var reader = new MemoryReader(buf);
+
+            var deser = WitnessCondition.DeserializeFrom(ref reader, WitnessCondition.MaxNestingDepth);
+            Assert.AreEqual(nested, deser);
+
+            nested = new AndCondition
+            {
+                Expressions = [
+                    new AndCondition { Expressions = [new BooleanCondition { Expression = true }] }
+                    ]
+            };
+
+            buf = nested.ToArray();
+            reader = new MemoryReader(buf);
+
+            deser = WitnessCondition.DeserializeFrom(ref reader, WitnessCondition.MaxNestingDepth);
+            Assert.AreEqual(nested, deser);
+
+            nested = new NotCondition
+            {
+                Expression = new NotCondition
+                {
+                    Expression = new BooleanCondition { Expression = true }
+                }
+            };
+
+            buf = nested.ToArray();
+            reader = new MemoryReader(buf);
+
+            deser = WitnessCondition.DeserializeFrom(ref reader, WitnessCondition.MaxNestingDepth);
+            Assert.AreEqual(nested, deser);
+
+            // Overflow maxNestingDepth
+            nested = new OrCondition
+            {
+                Expressions = [
+                    new OrCondition {
+                        Expressions = [
+                            new OrCondition { Expressions = [new BooleanCondition { Expression = true }] }
+                            ]
+                        }
+                    ]
+            };
+
+            buf = nested.ToArray();
+            reader = new MemoryReader(buf);
+
+            var exceptionHappened = false;
+            // CS8175 prevents from using Assert.ThrowsException here
+            try
+            {
+                WitnessCondition.DeserializeFrom(ref reader, WitnessCondition.MaxNestingDepth);
+            }
+            catch (FormatException)
+            {
+                exceptionHappened = true;
+            }
+            Assert.IsTrue(exceptionHappened);
+
+            nested = new AndCondition
+            {
+                Expressions = [
+                    new AndCondition {
+                        Expressions = [
+                            new AndCondition { Expressions = [new BooleanCondition { Expression = true }] }
+                            ]
+                        }
+                    ]
+            };
+
+            buf = nested.ToArray();
+            reader = new MemoryReader(buf);
+
+            exceptionHappened = false;
+            // CS8175 prevents from using Assert.ThrowsException here
+            try
+            {
+                WitnessCondition.DeserializeFrom(ref reader, WitnessCondition.MaxNestingDepth);
+            }
+            catch (FormatException)
+            {
+                exceptionHappened = true;
+            }
+            Assert.IsTrue(exceptionHappened);
+
+            nested = new NotCondition
+            {
+                Expression = new NotCondition
+                {
+                    Expression = new NotCondition
+                    {
+                        Expression = new BooleanCondition { Expression = true }
+                    }
+                }
+            };
+
+            buf = nested.ToArray();
+            reader = new MemoryReader(buf);
+
+            exceptionHappened = false;
+            // CS8175 prevents from using Assert.ThrowsException here
+            try
+            {
+                WitnessCondition.DeserializeFrom(ref reader, WitnessCondition.MaxNestingDepth);
+            }
+            catch (FormatException)
+            {
+                exceptionHappened = true;
+            }
+            Assert.IsTrue(exceptionHappened);
+        }
     }
 }