Enable nullable annotations for Volo.Abp.Serialization

framework/src/Volo.Abp.Serialization/Volo.Abp.Serialization.csproj

@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.Serialization</AssemblyName>
     <PackageId>Volo.Abp.Serialization</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>

framework/src/Volo.Abp.Serialization/Volo/Abp/Serialization/DefaultObjectSerializer.cs

@@ -15,7 +15,7 @@ public class DefaultObjectSerializer : IObjectSerializer, ITransientDependency
         _serviceProvider = serviceProvider;
     }
 
-    public virtual byte[] Serialize<T>(T obj)
+    public virtual byte[]? Serialize<T>(T? obj)
     {
         if (obj == null)
         {
@@ -35,8 +35,7 @@ public class DefaultObjectSerializer : IObjectSerializer, ITransientDependency
         return AutoSerialize(obj);
     }
 
-    [CanBeNull]
+    public virtual T? Deserialize<T>(byte[]? bytes)
-    public virtual T Deserialize<T>(byte[] bytes)
     {
         if (bytes == null)
         {
@@ -61,7 +60,7 @@ public class DefaultObjectSerializer : IObjectSerializer, ITransientDependency
         return JsonSerializer.SerializeToUtf8Bytes(obj);
     }
 
-    protected virtual T AutoDeserialize<T>(byte[] bytes)
+    protected virtual T? AutoDeserialize<T>(byte[] bytes)
     {
         return JsonSerializer.Deserialize<T>(bytes);
     }

framework/src/Volo.Abp.Serialization/Volo/Abp/Serialization/IObjectSerializer.cs

@@ -2,14 +2,14 @@
 
 public interface IObjectSerializer
 {
-    byte[] Serialize<T>(T obj);
+    byte[]? Serialize<T>(T? obj);
 
-    T Deserialize<T>(byte[] bytes);
+    T? Deserialize<T>(byte[] bytes);
 }
 
 public interface IObjectSerializer<T>
 {
-    byte[] Serialize(T obj);
+    byte[]? Serialize(T? obj);
 
-    T Deserialize(byte[] bytes);
+    T? Deserialize(byte[]? bytes);
 }