GuardrailAction is unexpectedly null when explicit filters don't match anything in the KB

[hughesjs]

Describe the bug

We've just hit a NullReferenceException in our code because the nullability annotations on Amazon.BedrockAgentRuntime.Model.RetrieveAndGenerateResponse indicate that GuardrailAction is not nullable; yet it returns null in certain cases.

This seems to happen when we add manual filters for the kb that don't match anything. If there is no guardrail action and a query submits successfully GuardrailAction isn't null, and the Value is "NONE"

Regression Issue

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Expected Behavior

response.GuardrailAction should never be null (as per nullability annotations).

GuardrailAction.Value should be "NONE" to be consistent with what happens when a successful query is sent.

Current Behavior

RetrieveAndGenerateResponse.GuardrailAction is null

Reproduction Steps

1. Submit a RetrieveAndGenerateRequest with filters that match no objects in the kb
2. Observe that response.GuardrailAction is null

Possible Solution

Ideally, ensure that GuardrailAction != null && GuardrailAction.Value == "NONE" in this case.

A worse solution would just be to use the nullability annotations

Additional Information/Context

No response

AWS .NET SDK and/or Package version used

AWSSDK.BedrockAgentRuntime v4.0.4.3

Targeted .NET Platform

dotnet 8

Operating System and version

Windows 11, Arch Linux, Ubuntu

[sankettangade]

Thank you for reporting this issue with GuardrailAction. We're working to reproduce the behavior you've described. Could you please provide a minimal reproduction example with your filter configuration and KB setup? This will help us investigate and implement the appropriate fix.

We'll update you once we've verified the behavior on our end.