fix: make optional properties of bindings nullable

src/LEGO.AsyncAPI.Readers/ParseNodes/ParseNode.cs

@@ -94,21 +94,41 @@ public virtual string GetScalarValue()
             throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
         }
 
+        public virtual string GetScalarValueOrDefault(string defaultValue)
+        {
+            throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
+        }
+
         public virtual bool GetBooleanValue()
         {
             throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
         }
 
+        public virtual bool? GetBooleanValueOrDefault(bool? defaultValue)
+        {
+            throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
+        }
+
         public virtual int GetIntegerValue()
         {
             throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
         }
 
+        public virtual int? GetIntegerValueOrDefault(int? defaultValue)
+        {
+            throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
+        }
+
         public virtual long GetLongValue()
         {
             throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
         }
 
+        public virtual long? GetLongValueOrDefault(long? defaultValue)
+        {
+            throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
+        }
+
         public virtual List<IAsyncApiAny> CreateListOfAny()
         {
             throw new AsyncApiReaderException("Cannot create a list from this type of node.", this.Context);

src/LEGO.AsyncAPI.Readers/ParseNodes/ValueNode.cs

@@ -29,6 +29,16 @@ public override string GetScalarValue()
             return this.node.Value;
         }
 
+        public override string GetScalarValueOrDefault(string defaultValue)
+        {
+            if (this.node.Value is not null)
+            {
+                return this.node.Value;
+            }
+
+            return defaultValue;
+        }
+
         public override int GetIntegerValue()
         {
             if (int.TryParse(this.node.Value, out int value))
@@ -39,6 +49,16 @@ public override int GetIntegerValue()
             throw new AsyncApiReaderException("Value could not parse to integer", this.node);
         }
 
+        public override int? GetIntegerValueOrDefault(int? defaultValue)
+        {
+            if (int.TryParse(this.node.Value, out int value))
+            {
+                return value;
+            }
+
+            return defaultValue;
+        }
+
         public override long GetLongValue()
         {
             if (long.TryParse(this.node.Value, out long value))
@@ -49,6 +69,16 @@ public override long GetLongValue()
             throw new AsyncApiReaderException("Value could not parse to long", this.node);
         }
 
+        public override long? GetLongValueOrDefault(long? defaultValue)
+        {
+            if (long.TryParse(this.node.Value, out long value))
+            {
+                return value;
+            }
+
+            return defaultValue;
+        }
+
         public override bool GetBooleanValue()
         {
             if (bool.TryParse(this.node.Value, out bool value))
@@ -59,6 +89,16 @@ public override bool GetBooleanValue()
             throw new AsyncApiReaderException("Value could not parse to bool", this.node);
         }
 
+        public override bool? GetBooleanValueOrDefault(bool? defaultValue)
+        {
+            if (bool.TryParse(this.node.Value, out bool value))
+            {
+                return value;
+            }
+
+            return defaultValue;
+        }
+
         public override IAsyncApiAny CreateAny()
         {
             var value = this.GetScalarValue();

src/LEGO.AsyncAPI/Models/Bindings/Kafka/KafkaChannelBinding.cs

@@ -20,12 +20,12 @@ public class KafkaChannelBinding : IChannelBinding
         /// <summary>
         /// Number of partitions configured on this topic (useful to know how many parallel consumers you may run).
         /// </summary>
-        public int Partitions { get; set; }
+        public int? Partitions { get; set; }
 
         /// <summary>
         /// Number of replicas configured on this topic.
         /// </summary>
-        public int Replicas { get; set; }
+        public int? Replicas { get; set; }
 
         /// <summary>
         /// Topic configuration properties that are relevant for the API.

src/LEGO.AsyncAPI/Models/Bindings/Kafka/TopicConfigurationObject.cs

@@ -17,22 +17,22 @@ public class TopicConfigurationObject : IAsyncApiElement
         /// <summary>
         /// The retention.ms configuration option.
         /// </summary>
-        public int RetentionMiliseconds { get; set; }
+        public int? RetentionMiliseconds { get; set; }
 
         /// <summary>
         /// The retention.bytes configuration option.
         /// </summary>
-        public int RetentionBytes { get; set; }
+        public int? RetentionBytes { get; set; }
 
         /// <summary>
         /// The delete.retention.ms configuration option.
         /// </summary>
-        public int DeleteRetentionMiliseconds { get; set; }
+        public int? DeleteRetentionMiliseconds { get; set; }
 
         /// <summary>
         /// The max.message.bytes configuration option.
         /// </summary>
-        public int MaxMessageBytes { get; set; }
+        public int? MaxMessageBytes { get; set; }
 
         public void Serialize(IAsyncApiWriter writer)
         {

src/LEGO.AsyncAPI/Models/Bindings/Pulsar/PulsarChannelBinding.cs

@@ -20,12 +20,12 @@ public class PulsarChannelBinding : IChannelBinding
         /// <summary>
         /// persistence of the topic in Pulsar persistent or non-persistent.
         /// </summary>
-        public Persistence Persistence { get; set; }
+        public Persistence? Persistence { get; set; }
 
         /// <summary>
         /// Topic compaction threshold given in bytes.
         /// </summary>
-        public int Compaction { get; set; }
+        public int? Compaction { get; set; }
 
         /// <summary>
         /// A list of clusters the topic is replicated to.
@@ -40,12 +40,12 @@ public class PulsarChannelBinding : IChannelBinding
         /// <summary>
         /// Message Time-to-live in seconds. 
         /// </summary>
-        public int TTL { get; set; }
+        public int? TTL { get; set; }
 
         /// <summary>
         /// When Message deduplication is enabled, it ensures that each message produced on Pulsar topics is persisted to disk only once.
         /// </summary>
-        public bool Deduplication { get; set; }
+        public bool? Deduplication { get; set; }
 
         /// <summary>
         /// The version of this binding.

test/LEGO.AsyncAPI.Tests/Bindings/Pulsar/PulsarBindings_Should.cs

@@ -1,4 +1,6 @@
-namespace LEGO.AsyncAPI.Tests.Bindings.Pulsar
+using LEGO.AsyncAPI.Models.Bindings;
+
+namespace LEGO.AsyncAPI.Tests.Bindings.Pulsar
 {
     using FluentAssertions;
     using LEGO.AsyncAPI.Models;
@@ -64,6 +66,44 @@ public void PulsarChannelBinding_WithFilledObject_SerializesAndDeserializes()
             binding.Should().BeEquivalentTo(channel);
         }
 
+        [Test]
+        public void PulsarChannelBindingNamespaceDefaultToNull()
+        {
+            // Arrange
+            var actual =
+                @"bindings:
+  pulsar:
+    persistence: persistent";
+
+            // Act
+            // Assert
+            var binding = new AsyncApiStringReader().ReadFragment<AsyncApiChannel>(actual, AsyncApiVersion.AsyncApi2_0, out _);
+
+            Assert.AreEqual(null, ((PulsarChannelBinding)binding.Bindings[BindingType.Pulsar]).Namespace);
+        }
+
+        [Test]
+        public void PulsarChannelBindingPropertiesExceptNamespaceDefaultToNull()
+        {
+            // Arrange
+            var actual =
+                @"bindings:
+  pulsar:
+    namespace: staging";
+
+            // Act
+            // Assert
+            var binding = new AsyncApiStringReader().ReadFragment<AsyncApiChannel>(actual, AsyncApiVersion.AsyncApi2_0, out _);
+            var pulsarBinding = ((PulsarChannelBinding) binding.Bindings[BindingType.Pulsar]);
+
+            Assert.AreEqual(null, pulsarBinding.Persistence);
+            Assert.AreEqual(null, pulsarBinding.Compaction);
+            Assert.AreEqual(null, pulsarBinding.GeoReplication);
+            Assert.AreEqual(null, pulsarBinding.Retention);
+            Assert.AreEqual(null, pulsarBinding.TTL);
+            Assert.AreEqual(null, pulsarBinding.Deduplication);
+        }
+
         [Test]
         public void PulsarServerBinding_WithFilledObject_SerializesAndDeserializes()
         {
@@ -97,5 +137,77 @@ public void PulsarServerBinding_WithFilledObject_SerializesAndDeserializes()
             Assert.AreEqual(actual, expected);
             binding.Should().BeEquivalentTo(server);
         }
+
+        [Test]
+        public void ServerBindingVersionDefaultsToNull()
+        {
+            // Arrange
+            var expected =
+                @"url: https://example.com
+protocol: pulsar
+bindings:
+  pulsar:
+    tenant: contoso";
+
+            var server = new AsyncApiServer()
+            {
+                Url = "https://example.com",
+                Protocol = "pulsar",
+            };
+
+            server.Bindings.Add(new PulsarServerBinding
+            {
+                Tenant = "contoso",
+                BindingVersion = null,
+            });
+
+            // Act
+            var actual = server.SerializeAsYaml(AsyncApiVersion.AsyncApi2_0);
+            actual = actual.MakeLineBreaksEnvironmentNeutral();
+            expected = expected.MakeLineBreaksEnvironmentNeutral();
+
+            var binding = new AsyncApiStringReader().ReadFragment<AsyncApiServer>(actual, AsyncApiVersion.AsyncApi2_0, out _);
+
+            // Assert
+            Assert.AreEqual(actual, expected);
+            Assert.AreEqual(null, ((PulsarServerBinding)binding.Bindings[BindingType.Pulsar]).BindingVersion);
+            binding.Should().BeEquivalentTo(server);
+        }
+
+        [Test]
+        public void ServerTenantDefaultsToNull()
+        {
+            // Arrange
+            var expected =
+                @"url: https://example.com
+protocol: pulsar
+bindings:
+  pulsar:
+    bindingVersion: latest";
+
+            var server = new AsyncApiServer()
+            {
+                Url = "https://example.com",
+                Protocol = "pulsar",
+            };
+
+            server.Bindings.Add(new PulsarServerBinding
+            {
+                Tenant = null,
+                BindingVersion = "latest",
+            });
+
+            // Act
+            var actual = server.SerializeAsYaml(AsyncApiVersion.AsyncApi2_0);
+            actual = actual.MakeLineBreaksEnvironmentNeutral();
+            expected = expected.MakeLineBreaksEnvironmentNeutral();
+
+            var binding = new AsyncApiStringReader().ReadFragment<AsyncApiServer>(actual, AsyncApiVersion.AsyncApi2_0, out _);
+
+            // Assert
+            Assert.AreEqual(actual, expected);
+            Assert.AreEqual(null, ((PulsarServerBinding)binding.Bindings[BindingType.Pulsar]).Tenant);
+            binding.Should().BeEquivalentTo(server);
+        }
     }
 }

test/LEGO.AsyncAPI.Tests/Models/AsyncApiMessage_Should.cs

@@ -105,10 +105,10 @@ public void AsyncApiMessage_WithSchemaFormat_Serializes()
       type:
         - string
         - 'null'
-schemaFormat: application/vnd.aai.asyncapi+json;version=2.5.0";
+schemaFormat: application/vnd.aai.asyncapi+json;version=2.6.0";
 
                 var message = new AsyncApiMessage();
-                message.SchemaFormat = "application/vnd.aai.asyncapi+json;version=2.5.0";
+                message.SchemaFormat = "application/vnd.aai.asyncapi+json;version=2.6.0";
                 message.Payload = new AsyncApiSchema()
                 {
                     Properties = new Dictionary<string, AsyncApiSchema>()