Merge pull request #628 from SteveDunn/bug-stj-allows-nulls

Bug stj allows nulls

src/Vogen.SharedTypes/DeserializationOptions.cs

@@ -22,12 +22,18 @@ public enum DeserializationStrictness
     /// </summary>
     RunMyValidationMethod = 1 << 1,
 
+    /// <summary>
+    /// System.Text.Json only for now. By default, System.Text.Json allows nulls for reference types.
+    /// If you want to disallow this behaviour for value objects, then set this flag. 
+    /// </summary>
+    DisallowNulls = 1 << 2,
+
     /// <summary>
     /// If your Value Object has 'Instances', then those are considered valid during deserialization.
     /// If the incoming value doesn't match any known instance, and if your Value Object has a Validate method, it will
     /// be called to validate the incoming value during deserialization. 
     /// </summary>
     AllowValidAndKnownInstances = AllowKnownInstances | RunMyValidationMethod,
 
-    Default = AllowValidAndKnownInstances
+    Default = AllowValidAndKnownInstances,
 }

src/Vogen/Generators/Conversions/GenerateSystemTextJsonConversions.cs

@@ -1,4 +1,5 @@
-using Microsoft.CodeAnalysis.CSharp.Syntax;
+using System;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
 
 namespace Vogen.Generators.Conversions;
 
@@ -22,19 +23,35 @@ public string GenerateAnyBody(TypeDeclarationSyntax tds, VoWorkItem item)
         }
 
         string code = ResolveTemplate(item);
+
+        bool allowNullReferences = true;
+
+        if (item.IsTheWrapperAReferenceType)
+        {
+            // it's a class
+            if (item.Config.DeserializationStrictness.HasFlag(DeserializationStrictness.DisallowNulls))
+            {
+                allowNullReferences = false;
+            }
+
+        }
+
+        code = allowNullReferences ? CodeSections.CutSection(code, "__HANDLE_NULL__") : CodeSections.KeepSection(code, "__HANDLE_NULL__");
+
         if (code.Contains("__NORMAL__"))
         {
             (string keep, string cut) keepCut =
                 item.Config.Customizations.HasFlag(Customizations.TreatNumberAsStringInSystemTextJson)
-                    ? ("__STRING__", "__NORMAL__") : ("__NORMAL__", "__STRING__");
+                    ? ("__STRING__", "__NORMAL__")
+                    : ("__NORMAL__", "__STRING__");
 
             code = CodeSections.CutSection(code, keepCut.cut);
             code = CodeSections.KeepSection(code, keepCut.keep);
         }
 
         code = code.Replace("VOTYPE", item.VoTypeName);
         code = code.Replace("VOUNDERLYINGTYPE", item.UnderlyingTypeFullName);
-        
+
         return code;
     }
 

src/Vogen/Templates/AnyOtherType/AnyOtherType_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 var primitive = global::System.Text.Json.JsonSerializer.Deserialize<VOUNDERLYINGTYPE>(ref reader, options);

src/Vogen/Templates/Boolean/Boolean_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return VOTYPE.__Deserialize(reader.GetBoolean());

src/Vogen/Templates/Byte/Byte_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
 #if NET5_0_OR_GREATER

src/Vogen/Templates/Char/Char_SystemTextJsonConverter.cs

@@ -3,6 +3,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 var s = reader.GetString();

src/Vogen/Templates/DateOnly/DateOnly_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return VOTYPE.__Deserialize(reader.GetDateOnly());
@@ -20,6 +23,9 @@ public override void Write(System.Text.Json.Utf8JsonWriter writer, VOTYPE value,
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return new VOTYPE(global::System.DateOnly.ParseExact(reader.GetString(), "yyyy-MM-dd", global::System.Globalization.CultureInfo.InvariantCulture));

src/Vogen/Templates/DateTime/DateTime_SystemTextJsonConverter.cs

@@ -3,6 +3,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return VOTYPE.__Deserialize(reader.GetDateTime().ToUniversalTime());

src/Vogen/Templates/DateTimeOffset/DateTimeOffset_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return VOTYPE.__Deserialize(reader.GetDateTimeOffset());

src/Vogen/Templates/Decimal/Decimal_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
 #if NET5_0_OR_GREATER

src/Vogen/Templates/Double/Double_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
 #if NET5_0_OR_GREATER

src/Vogen/Templates/Guid/Guid_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return VOTYPE.__Deserialize(reader.GetGuid());

src/Vogen/Templates/Int/Int_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
 #if NET5_0_OR_GREATER

src/Vogen/Templates/Long/Long_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
     /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
 #if NET5_0_OR_GREATER

src/Vogen/Templates/Short/Short_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
 #if NET5_0_OR_GREATER

src/Vogen/Templates/Single/Single_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
 #if NET5_0_OR_GREATER

src/Vogen/Templates/String/String_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return VOTYPE.__Deserialize(reader.GetString());

src/Vogen/Templates/TimeOnly/TimeOnly_SystemTextJsonConverter.cs

@@ -4,6 +4,9 @@
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return VOTYPE.__Deserialize(reader.GetTimeOnly());
@@ -20,6 +23,9 @@ public override void Write(System.Text.Json.Utf8JsonWriter writer, VOTYPE value,
         /// </summary>
         public class VOTYPESystemTextJsonConverter : global::System.Text.Json.Serialization.JsonConverter<VOTYPE>
         {
+__HANDLE_NULL__ #if NET5_0_OR_GREATER            
+__HANDLE_NULL__            public override bool HandleNull => true;            
+__HANDLE_NULL__ #endif            
             public override VOTYPE Read(ref global::System.Text.Json.Utf8JsonReader reader, global::System.Type typeToConvert, global::System.Text.Json.JsonSerializerOptions options)
             {
                 return new VOTYPE(global::System.TimeOnly.Parse(reader.GetString(), global::System.Globalization.CultureInfo.InvariantCulture));

src/Vogen/VoWorkItem.cs

@@ -42,6 +42,7 @@ public INamedTypeSymbol UnderlyingType
     public bool IsTheUnderlyingAValueType { get; init; }
 
     public bool IsTheWrapperAValueType { get; init; }
+    public bool IsTheWrapperAReferenceType => !IsTheWrapperAValueType;
 
     public List<InstanceProperties> InstanceProperties { get; init; } = new();
 

tests/ConsumerTests/BugFixTests/BugFix624.cs

@@ -0,0 +1,52 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using System.Text.Json.Serialization.Metadata;
+using SystemTextJsonSerializer = System.Text.Json.JsonSerializer;
+
+namespace ConsumerTests.BugFixTests.BugFix624;
+
+[ValueObject<string>(conversions: Conversions.SystemTextJson)]
+public partial class NonStrictReferenceVo;
+
+[ValueObject<string>(conversions: Conversions.SystemTextJson, deserializationStrictness: DeserializationStrictness.DisallowNulls)]
+public partial class StrictReferenceVo;
+
+[ValueObject(conversions: Conversions.SystemTextJson)]
+public partial struct ValueVo;
+
+public class StrictContainer
+{
+    // ReSharper disable once NullableWarningSuppressionIsUsed
+    public StrictReferenceVo Rvo { get; set; } = null!;
+}
+
+public class NonStrictContainer
+{
+    // ReSharper disable once NullableWarningSuppressionIsUsed
+    public NonStrictReferenceVo Rvo { get; set; } = null!;
+}
+
+/// <summary>
+/// Fixes bug https://github.com/SteveDunn/Vogen/issues/624 where STJ
+/// deserialization would allow a null value object if it was a reference type
+/// </summary>
+public class Tests
+{
+    [Fact]
+    public void Should_throw_if_null()
+    {
+        string json = $$"""{"Rvo":null}""";
+
+        Action a = () => JsonSerializer.Deserialize<StrictContainer>(json);
+        a.Should().ThrowExactly<ValueObjectValidationException>().WithMessage("Cannot create a value object with null.");
+    }
+
+    [Fact]
+    public void Can_override_null_behaviour_to_not_throw()
+    {
+        string json = $$"""{"Rvo":null}""";
+
+        var x = JsonSerializer.Deserialize<NonStrictContainer>(json)!;
+        x.Rvo.Should().BeNull();
+    }
+}

tests/SnapshotTests/JsonNumberCustomizations/CustomizeNumbersAsStringsInSystemTextJson.cs → tests/SnapshotTests/SystemTextJsonGeneration/CustomizeNumbersAsStringsInSystemTextJson.cs

@@ -4,7 +4,7 @@
 using VerifyXunit;
 using Vogen;
 
-namespace SnapshotTests.JsonNumberCustomizations;
+namespace SnapshotTests.SystemTextJsonGeneration;
 
 /// <summary>
 /// These tests verify that types containing <see cref="Customizations.TreatNumberAsStringInSystemTextJson"/> are written correctly.
@@ -81,4 +81,5 @@ namespace Whatever
             .CustomizeSettings(s => s.UseFileName(TestHelper.ShortenForFilename(className)))
             .RunOnAllFrameworks();
     }
+
 }

tests/SnapshotTests/SystemTextJsonGeneration/DeserializationStrictnessTests.cs

@@ -0,0 +1,42 @@
+using System.Threading.Tasks;
+using VerifyXunit;
+using Vogen;
+
+namespace SnapshotTests.SystemTextJsonGeneration;
+
+[UsesVerify] 
+public class DeserializationStrictnessTests
+{
+    [Fact]
+    public Task Reference_value_objects_allow_nulls_by_default()
+    {
+        var source = """
+                     using Vogen;
+                     namespace Whatever;
+                     
+                     [ValueObject]
+                     public partial class ReferenceVo;
+                     """;
+
+        return new SnapshotRunner<ValueObjectGenerator>()
+            .WithSource(source)
+            .RunOnAllFrameworks();
+    }
+
+    [Fact]
+    public Task Can_disallow_nulls_for_reference_value_objects()
+    {
+        var source = """
+                     using Vogen;
+                     namespace Whatever;
+                     
+                     [ValueObject(deserializationStrictness: DeserializationStrictness.DisallowNulls)]
+                     public partial class ReferenceVo;
+                     """;
+
+        return new SnapshotRunner<ValueObjectGenerator>()
+            .WithSource(source)
+            .RunOnAllFrameworks();
+    }
+
+}