dify - 💡(How to fix) Fix Bug: External retrieval model response rejects empty score threshold [2 pull requests]

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Dify version

1.14.2

Cloud or Self Hosted

Self Hosted (Source)

Steps to reproduce

• Configure or load an external knowledge dataset whose retrieval model does not provide a numeric score_threshold.
• Request dataset details or any API response that serializes DatasetExternalRetrievalModelResponse.
• The response model validates score_threshold as a required float.

✔️ Expected Behavior

• External retrieval model responses should allow score_threshold to be empty when threshold filtering is disabled or not configured.
• The API should serialize the dataset response successfully with score_threshold: null.

❌ Actual Behavior

• score_threshold is typed as a required float.
• Responses with an empty score threshold can fail validation or serialization even though score_threshold_enabled is already optional.