undefined cannot be accepted as a member of GPUPipelineLayoutDescriptor.bindGroupLayouts

[Jiawei-Shao]

Now in dist/index.d.ts GPUPipelineLayoutDescriptor is defined as below, which means the member of bindGroupLayouts in GPUPipelineLayoutDescriptor can not be undefined:

interface GPUPipelineLayoutDescriptor
  extends GPUObjectDescriptorBase {
  /**
   * A list of optional {@link GPUBindGroupLayout}s the pipeline will use. Each element corresponds
   * to a @group attribute in the {@link GPUShaderModule}, with the `N`th element corresponding
   * with `@group(N)`.
   */
  bindGroupLayouts: Iterable<GPUBindGroupLayout | null>;
}

While according to WebGPU SPEC, undefined is valid as a member of bindGroupLayouts in GPUPipelineLayoutDescriptor:

dictionary GPUPipelineLayoutDescriptor
         : GPUObjectDescriptorBase {
    required sequence<GPUBindGroupLayout?> bindGroupLayouts;
};

Does it mean the definition of GPUPipelineLayoutDescriptor in dist/index.d.ts doesn't follow the WebGPU SPEC?

[kainino0x]

You're correct, WebIDL T? should be translated as T | null | undefined.

It would be best to fix this in the generator, but if that's difficult we can fix it in dist/index.d.ts and add a note in https://github.com/gpuweb/types/blob/main/README.md#intentional-differences-between-generator-output-and-final-result