vllm-project/vllm · error · ValueError

Quantization method {name} is an override but is has not bee

Error message

Quantization method {name} is an override but is has not been added to the `overrides` list above. This is necessary to ensure that the overrides are checked in order of preference.

What it means

Error "Quantization method {name} is an override but is has not been added to the `overrides` list above. This is necessary to ensure that the overrides are checked in order of preference." thrown in vllm-project/vllm.

Source

Thrown at vllm/config/model.py:1258

            # them at the start of the list so custom overrides have preference
            # over the built-in ones.
            quantization_methods = quantization_methods + overrides

            # Detect which checkpoint is it
            for name in quantization_methods:
                method = me_quant.get_quantization_config(name)
                quantization_override = method.override_quantization_method(
                    quant_cfg, self.quantization, hf_config=self.hf_config
                )
                if quantization_override is not None:
                    # Raise error if the override is not custom (custom would
                    # be in QUANTIZATION_METHODS but not QuantizationMethods)
                    # and hasn't been added to the overrides list.
                    if (
                        name in get_args(me_quant.QuantizationMethods)
                        and name not in overrides
                    ):
                        raise ValueError(
                            f"Quantization method {name} is an override but "
                            "is has not been added to the `overrides` list "
                            "above. This is necessary to ensure that the "
                            "overrides are checked in order of preference."
                        )
                    quant_method = quantization_override
                    self.quantization = quantization_override
                    break

            quant_method = quant_method if quant_method != "" else None
            # Verify quantization configurations.
            if self.quantization is None:
                self.quantization = quant_method
            elif self.quantization != quant_method:
                raise ValueError(
                    "Quantization method specified in the model config "
                    f"({quant_method}) does not match the quantization "
                    f"method specified in the `quantization` argument "

View on GitHub (pinned to c794754062)

Solutions

1. Add the quantization method name to the `overrides` list in the config so overrides are checked in order of preference.

When it happens

Trigger: Raised at vllm/config/model.py:1258 when validation fails: Quantization method override has not been added to the `overrides` list. Typically triggered by an incompatible or incomplete vLLM configuration, an unsupported platform/backend combination, or a runtime resource/dependency that is missing.

Common situations: Commonly encountered at vllm/config/model.py:1258 during vLLM startup/config validation or runtime setup when: (1) conflicting CLI flags or config fields are combined, (2) the current platform (CUDA/ROCm/CPU/XPU) or installed optional packages do not support the requested feature, or (3) a required value is absent or out of range. Resolve by correcting the configuration as described in the message, or by selecting a supported alternative.

AI-assisted analysis of vllm-project/vllm@c794754062 (2026-08-14). Data as JSON: /api/errors/3997ef4d15f57453. Report an issue: GitHub.