stride3d/stride · error · InvalidOperationException

Shader buffers not loaded for

Error message

Shader buffers not loaded for {classSource.ClassName}

What it means

Thrown by LoadExternalShaderType when the ShaderClassInstantiation has a null Buffer, meaning the shader's parse buffers were never loaded before attempting to create the shader type. The loader requires the source buffers to build the ShaderDefinition.

Solutions

Ensure the shader's source buffers are loaded (classSource.Buffer populated) before resolving its type
Check for earlier load/parse errors of the external shader file and fix the root cause
Verify the shader file exists and is accessible so the loading step can populate the buffer

Example fix

// before
var type = ShaderClass.LoadExternalShaderType(table, context, classSource); // Buffer null
// after
classSource.LoadBuffers(); // or use the loading API that populates Buffer
var type = ShaderClass.LoadExternalShaderType(table, context, classSource);

Defensive patterns

Strategy: validation

Validate before calling

if (classSource.Buffer is null)
    throw new InvalidOperationException($"Load buffers for {classSource.ClassName} before resolving its type");

Type guard

bool BuffersLoaded(ShaderClassInstantiation c) => c.Buffer is not null;

Try / catch

try { var t = ShaderDefinition.LoadExternalShaderType(table, context, classSource); }
catch (InvalidOperationException ex) { log.Error($"Buffer not loaded: {ex.Message}"); throw; }

Prevention

Always run the buffer-loading step before type resolution
Check earlier file load errors
Never construct ShaderClassInstantiation manually without loading buffers

When it happens

Trigger: Calling LoadExternalShaderType (or ShaderClass resolution that reaches it) on a classSource produced without the buffer-loading preprocessing step, e.g. after a failed or skipped parse of the external shader file.

Common situations: External shader file failed to load/parse earlier leaving Buffer null; manually constructed ShaderClassInstantiation used without running the buffer loading step; asset pipeline changes where shader files are not read before compilation.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/06b0a42ed804373d. Report an issue: GitHub.

Appendix: source

Thrown at sources/shaders/Stride.Shaders.Parsers/Parsing/SDSL/AST/Shader.cs:766

    public static ShaderDefinition LoadAndCacheExternalShaderType(SymbolTable table, SpirvContext context, ShaderClassInstantiation classSource, SpirvContext declaringContext)
    {
        // Already processed?
        if (table.DeclaredShaders.TryGetValue(classSource.ToClassNameWithGenerics(), out var cachedShader))
            return cachedShader;

        if (classSource.Buffer == null)
        {
            var shader = SpirvBuilder.GetOrLoadShader(table.ShaderLoader, classSource, table.CurrentMacros.AsSpan(), ResolveStep.Compile, declaringContext);
            classSource.Buffer = shader;
        }
        var shaderType = LoadExternalShaderType(table, context, classSource);
        return shaderType;
    }

    public static ShaderDefinition LoadExternalShaderType(SymbolTable table, SpirvContext context, ShaderClassInstantiation classSource)
    {
        var shaderBuffers = classSource.Buffer ?? throw new InvalidOperationException($"Shader buffers not loaded for {classSource.ClassName}");

        var shaderType = CreateShaderType(table, context, shaderBuffers, classSource);

        RegisterShaderType(table, shaderType);

        return shaderType;
    }


    public override string ToString()
    {
        return
$"""
Class : {Name}
Generics : {string.Join(", ", Generics)}
Inherits from : {string.Join(", ", Mixins)}
Body :
{string.Join("\n", Elements)}

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