Bug 267584 – Silent failure when creating additional createCommandEncoder

• Status: NEW
• Component: WebGPU

[Aura Munoz]

When incorrectly creating an additional command encoder in the render loop, Safari freezes and turns the whole application unresponsive. Instead, it should throw a warning or an error

Just add an additional device.createCommandEncoder(); to the webGPU samples https://github.com/webgpu/webgpu-samples/blob/0721d17d9f489b7b4fb1091f98282627c6f5d173/src/sample/rotatingCube/main.ts#L182

```
  function frame() {
    // Sample is no longer the active page.
    if (!pageState.active) return;

    const transformationMatrix = getTransformationMatrix();
    device.queue.writeBuffer(
      uniformBuffer,
      0,
      transformationMatrix.buffer,
      transformationMatrix.byteOffset,
      transformationMatrix.byteLength
    );
    renderPassDescriptor.colorAttachments[0].view = context
      .getCurrentTexture()
      .createView();

    const commandEncoderOther = device.createCommandEncoder();
    const commandEncoder = device.createCommandEncoder();
    const passEncoder = commandEncoder.beginRenderPass(renderPassDescriptor);
    passEncoder.setPipeline(pipeline);
    passEncoder.setBindGroup(0, uniformBindGroup);
    passEncoder.setVertexBuffer(0, verticesBuffer);
    passEncoder.draw(cubeVertexCount, 1, 0, 0);
    passEncoder.end();
    device.queue.submit([commandEncoder.finish()]);

    requestAnimationFrame(frame);
  }
  requestAnimationFrame(frame);
};
```

This will freeze Safari

[Mike Wyrzykowski]

Likely dupe of https://bugs.webkit.org/show_bug.cgi?id=267285

validation for command encoding is not yet implemented

[Radar WebKit Bug Importer]

<rdar://problem/121441067>