[BUG] Partial Image Data is lost during serialization

[bw-flagship]

Describe the bug

I noticed that partialImageBytes is not filled correctly in StreamingResponseImageGenerationCallPartialImageUpdate.

In the json, the field is "partial_image_b64"

But the code is expecting a different prop:

if (prop.NameEquals("PartialImageBytes"u8))
{
    partialImageBytes = BinaryData.FromBytes(prop.Value.GetBytesFromBase64("D"));
    continue;
}

In addition, I was wondering why we transform the b64 to BinaryData in the library?
In streaming usecases, oftentimes the image stream will be passed directly from the lib via an api to some frontend, where you would use b64 anyways.

In my case, openai-dotnet transforms then b64 from openAi to BinaryData and afterwards I immediately transform it back to b64. Wouldn't it make sense to expose the b64 directly?

Steps to reproduce

• Create a Streaming response with the image generation tool
• Check the content of StreamingResponseImageGenerationCallPartialImageUpdate. It will have partialImageBytes = null.

Code snippets

OS

MacOs

.NET version

9.0

Library version

2.6.0

[jsquire]

Hi @bw-flagship. Thanks for reaching out and we regret that you're experiencing difficulties. Looking things over, the REST API spec has this modeled correctly. However, the generated code is reading the wrong field. We were able to trace to a bug in the code generator, which is applying a client type rename to serialization incorrectly.

We've filed a generator bug for the root cause. In the short term, we have an alternate customization out in #807 that will fix the issue in our next release. In the meantime, you can work around this in your application by using the new JSON Patch feature available in v2.6.0, which would look something like:

if (streamingEvent is StreamingResponseImageGenerationCallPartialImageUpdate imageUpdate)
{
    var base64Image = imageUpdate.Patch.GetString("$.partial_image_b64"u8);
}

[bw-flagship]

@jsquire thanks for the reply, I can confirm that the workaround works!