From 93e561ec4dfadba837e47f63fb9d9ec971b6ba65 Mon Sep 17 00:00:00 2001 From: Harry Mellor <19981378+hmellor@users.noreply.github.com> Date: Thu, 17 Apr 2025 01:35:35 +0100 Subject: [PATCH] Improve error for structured output backend selection (#16717) Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com> --- vllm/v1/engine/processor.py | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/vllm/v1/engine/processor.py b/vllm/v1/engine/processor.py index 225e78f5..be7e3709 100644 --- a/vllm/v1/engine/processor.py +++ b/vllm/v1/engine/processor.py @@ -155,10 +155,13 @@ class Processor: "supported in V1.") if params.guided_decoding.backend: if params.guided_decoding.backend != engine_level_backend: - raise ValueError("Request-level structured output backend " - "must match engine-level backend. " - f"{params.guided_decoding.backend}" - f" != {engine_level_backend}") + raise ValueError( + "Request-level structured output backend selection is no " + "longer supported. The request specified " + f"'{params.guided_decoding.backend}', but vLLM was " + f"initialised with '{engine_level_backend}'. This error " + "can be resolved by removing backend selection from the " + "request.") else: params.guided_decoding.backend = engine_level_backend