webgpu:api,operation,labels:wrappers_do_not_share_labels:* calls createRenderPipeline with no target

[jimblandy]

The algorithm validatingGPURenderPipelineDescriptor says:

• There must exist at least one attachment, either:

  • A non-null value in descriptor.fragment.targets, or

  • A descriptor.depthStencil.

But webgpu:api,operation,labels:wrappers_do_not_share_labels:* tries to create a render pipeline without any attachments:

    const pipeline = t.device.createRenderPipeline({
      layout: 'auto',
      vertex: {
        module,
        entryPoint: 'main',
      },
    });

[kainino0x]

Thank you for catching this!
I am surprised that Dawn passes this test. I thought we had tests for this validation. I'm pretty sure we do for render passes, I guess we missed it for render pipelines. I have filed https://crbug.com/341812551

We'll also of course need to test that, since I guess we're not testing it. (EDIT: ... which Erich already filed. #3755)

[ErichDonGubler]

Resolved with #3756. I've filed an issue for validating this specific case at #3755.