NullReferenceException when compiling shaders containing buffer pointers with reflection

[nicolasgustafsson]

The reflection throws NullReferenceException trying to parse pointers in the json. Compiling without reflection data works as expected.

Version: Slangc.NET 2025.19.1

Stacktrace:

   at Slangc.NET.SlangType.PointerProperties..ctor(JsonObject reader)
   at Slangc.NET.SlangType..ctor(JsonObject reader)
   at Slangc.NET.SlangVar..ctor(JsonObject reader)
   at Slangc.NET.SlangType.StructProperties.<>c.<.ctor>b__0_0(JsonNode reader)
   at System.Linq.Enumerable.IListSelectIterator`2.Fill(IList`1 source, Span`1 results, Func`2 func)
   at System.Linq.Enumerable.IListSelectIterator`2.ToArray()
   at Slangc.NET.SlangType.StructProperties..ctor(JsonObject reader)
   at Slangc.NET.SlangType..ctor(JsonObject reader)
   at Slangc.NET.SlangParameter..ctor(JsonObject reader)
   at Slangc.NET.SlangReflection.<>c.<.ctor>b__2_0(JsonNode reader)
   at System.Linq.Enumerable.IListSelectIterator`2.Fill(IList`1 source, Span`1 results, Func`2 func)
   at System.Linq.Enumerable.IListSelectIterator`2.ToArray()
   at Slangc.NET.SlangReflection..ctor(IntPtr request, Boolean parseJson)
   at Slangc.NET.SlangCompiler.CompileWithReflection(String[] args, SlangReflection& reflection)

Repro shader code:

struct Vertex 
{
    float3 position;
};

struct VertexStageOutput
{
    float4          sv_position     : SV_Position;
};

struct VertexBuffer
{
    Vertex vertices[];
}

struct InputData 
{
    VertexBuffer* VertexBuffer;
};

InputData PushConstants; 

[shader("vertex")]
VertexStageOutput main(uint vertexID : SV_VertexID)
{
    VertexStageOutput output;
    
    return output; 
}

Repro:

1. Compile above shader code with reflection.

Expected Result:
Shader successfully compiles, and the reflection out parameter is set.

Actual Result:
CompileWithReflection throws NullReferenceException.

Workaround:
Copying the entire SlangCompiler class, and changing SlangReflection constructor argument to not parse the json should allow me to manually parse the json myself, though I have not tried this yet.

[qian-o]

There is indeed this issue, I have a problem with my deserialization logic, I have fixed it, I will update this library after slang releases a new version.

[nicolasgustafsson]

Wonderful, thank you!

[qian-o]

A new version has been released — please try again. Currently SlangReflection does not automatically deserialize JSON during construction; if you need to deserialize manually, a Deserialize method has been added for that purpose. If you still encounter issues while using it, please post a minimal reproducible example and the exception stack, and I will continue to follow up.