[Frontend] Support using chat template as custom score template for reranking models (#30550)

Signed-off-by: Jakub Zakrzewski <jzakrzewski@nvidia.com>
Signed-off-by: wang.yuqi <yuqi.wang@daocloud.io>
Signed-off-by: wang.yuqi <noooop@126.com>
Co-authored-by: wang.yuqi <yuqi.wang@daocloud.io>
This commit is contained in:
Jakub Zakrzewski
2025-12-23 12:19:16 +01:00
committed by GitHub
parent 27c6c2f98c
commit 23daef548d
19 changed files with 663 additions and 46 deletions

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@@ -0,0 +1,352 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from unittest.mock import patch
import pytest
from vllm.config import ModelConfig
from vllm.entrypoints.chat_utils import ChatTemplateResolutionError
from vllm.entrypoints.score_utils import get_score_prompt
from vllm.inputs import TokensPrompt
from vllm.tokenizers import get_tokenizer
# A cross-encoder model for testing
CROSS_ENCODER_MODEL_ID = "cross-encoder/ms-marco-MiniLM-L-6-v2"
def assert_prompt_tokenization_consistent(
tokenizer, full_prompt, engine_prompt, add_special_tokens=True
):
"""Verify that engine_prompt token_ids match tokenizing full_prompt."""
expected_ids = tokenizer(full_prompt, add_special_tokens=add_special_tokens)[
"input_ids"
]
actual_ids = engine_prompt["prompt_token_ids"]
assert actual_ids == expected_ids, (
f"Token IDs don't match.\nExpected: {expected_ids}\nActual: {actual_ids}"
)
@pytest.fixture(scope="module")
def cross_encoder_model_config():
return ModelConfig(
CROSS_ENCODER_MODEL_ID,
runner="pooling",
)
@pytest.fixture(scope="module")
def cross_encoder_tokenizer(cross_encoder_model_config):
return get_tokenizer(
CROSS_ENCODER_MODEL_ID,
trust_remote_code=cross_encoder_model_config.trust_remote_code,
)
@pytest.fixture(scope="module")
def llm_reranker_model_config():
"""Model config for LLM-as-reranker style (no pad token)."""
config = ModelConfig(
CROSS_ENCODER_MODEL_ID,
runner="pooling",
)
# use_pad_token is a property that reads from hf_config,
# so we set it there to override the default (True)
config.hf_config.use_pad_token = False
return config
@pytest.fixture
def tokenization_kwargs():
"""Common tokenization kwargs used across tests."""
return {"add_special_tokens": True, "return_tensors": None}
@pytest.fixture
def mock_model_with_score_template():
"""Mock model class that supports score template and tracks post_process calls."""
class MockModelWithScoreTemplate:
supports_score_template = True
post_process_called: list[TokensPrompt] = []
@staticmethod
def get_score_template(p1: str, p2: str) -> str:
return f"[QUERY]{p1}[SEP][DOC]{p2}"
@staticmethod
def post_process_tokens(prompt: TokensPrompt) -> None:
MockModelWithScoreTemplate.post_process_called.append(prompt)
return MockModelWithScoreTemplate
@pytest.fixture
def mock_model_no_score_template():
"""Mock model class that does not support score template."""
class MockModelNoScoreTemplate:
supports_score_template = False
return MockModelNoScoreTemplate
class TestGetScorePrompt:
"""Tests for the get_score_prompt function."""
def test_tokenization_kwargs_passed_through(
self,
llm_reranker_model_config,
cross_encoder_tokenizer,
):
"""Test that tokenization kwargs are properly passed through."""
data_1 = "Query text"
data_2 = "Document text"
# Test with truncation - custom kwargs for this test
custom_tokenization_kwargs = {
"add_special_tokens": True,
"return_tensors": None,
"truncation": True,
"max_length": 20,
}
full_prompt, engine_prompt = get_score_prompt(
llm_reranker_model_config,
cross_encoder_tokenizer,
custom_tokenization_kwargs,
data_1,
data_2,
)
assert isinstance(full_prompt, str)
assert "prompt_token_ids" in engine_prompt
# With max_length=20 and truncation, should not exceed this
assert len(engine_prompt["prompt_token_ids"]) <= 20
# Since truncation was applied, token_ids should be a prefix of full encoding
full_ids = cross_encoder_tokenizer(full_prompt, add_special_tokens=True)[
"input_ids"
]
actual_ids = engine_prompt["prompt_token_ids"]
assert full_ids[: len(actual_ids)] == actual_ids, (
f"Token IDs are not a prefix of full encoding.\n"
f"Full IDs: {full_ids}\n"
f"Actual IDs: {actual_ids}"
)
def test_model_supports_score_template(
self,
cross_encoder_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
mock_model_with_score_template,
):
"""Test when model supports score template (no score_template arg)."""
with patch(
"vllm.model_executor.model_loader.get_model_cls",
return_value=mock_model_with_score_template,
):
full_prompt, engine_prompt = get_score_prompt(
cross_encoder_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
"query text",
"document text",
)
assert full_prompt == "[QUERY]query text[SEP][DOC]document text"
assert "prompt_token_ids" in engine_prompt
assert len(engine_prompt["prompt_token_ids"]) > 0
assert_prompt_tokenization_consistent(
cross_encoder_tokenizer, full_prompt, engine_prompt
)
def test_model_supports_score_template_but_custom_template_provided(
self,
cross_encoder_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
mock_model_with_score_template,
):
"""Test when model supports score template but custom template is provided."""
template = (
'TEMPLATE_USED {{ messages[0]["content"] }} {{ messages[1]["content"] }}'
)
with (
patch(
"vllm.model_executor.model_loader.get_model_cls",
return_value=mock_model_with_score_template,
),
):
full_prompt, engine_prompt = get_score_prompt(
cross_encoder_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
"query",
"doc",
score_template=template, # Providing a template
)
assert "prompt_token_ids" in engine_prompt
assert full_prompt == "TEMPLATE_USED query doc"
assert_prompt_tokenization_consistent(
cross_encoder_tokenizer, full_prompt, engine_prompt
)
def test_not_using_default_template(
self,
llm_reranker_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
mock_model_no_score_template,
):
# FIXME: Models implementing SupportsScoreTemplate must use their custom
# template implementation by default to preserve existing functionality.
# Attempting to use tokenizer_config.json templates would most likely break
# these models, as often they just inherit the template from the original LLM.
# CLI --chat-template overrides are still supported.
with (
patch(
"vllm.model_executor.model_loader.get_model_cls",
return_value=mock_model_no_score_template,
),
patch(
"vllm.entrypoints.score_utils.apply_hf_chat_template",
return_value="test querytest doc",
),
):
full_prompt, engine_prompt = get_score_prompt(
llm_reranker_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
"test query",
"test doc",
)
assert full_prompt == "test querytest doc"
assert "prompt_token_ids" in engine_prompt
assert_prompt_tokenization_consistent(
cross_encoder_tokenizer, full_prompt, engine_prompt
)
def test_fallback_with_pad_token(
self,
cross_encoder_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
mock_model_no_score_template,
):
"""Test fallback path when ChatTemplateResolutionError
and use_pad_token=True."""
with (
patch(
"vllm.model_executor.model_loader.get_model_cls",
return_value=mock_model_no_score_template,
),
patch(
"vllm.entrypoints.score_utils.apply_hf_chat_template",
side_effect=ChatTemplateResolutionError("No template"),
),
):
full_prompt, engine_prompt = get_score_prompt(
cross_encoder_model_config, # use_pad_token=True
cross_encoder_tokenizer,
tokenization_kwargs,
"query",
"document",
)
assert "prompt_token_ids" in engine_prompt
# Should have token_type_ids from text_pair encoding
assert "token_type_ids" in engine_prompt
assert "query" in full_prompt
assert "document" in full_prompt
assert full_prompt != "querydocument"
assert (
engine_prompt["prompt_token_ids"]
== cross_encoder_tokenizer(
"query", text_pair="document", add_special_tokens=True
)["input_ids"]
)
# FIXME(?): add_special_tokens=False is needed because in this case
# full_prompt is obtained by decoding the tokenized prompt, which includes
# special tokens and we would get duplicated special tokens otherwise.
# This is inconsistent with other cases.
assert_prompt_tokenization_consistent(
cross_encoder_tokenizer,
full_prompt,
engine_prompt,
add_special_tokens=False,
)
def test_fallback_without_pad_token(
self,
llm_reranker_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
mock_model_no_score_template,
):
"""Test fallback path when ChatTemplateResolutionError
and use_pad_token=False."""
with (
patch(
"vllm.model_executor.model_loader.get_model_cls",
return_value=mock_model_no_score_template,
),
patch(
"vllm.entrypoints.score_utils.apply_hf_chat_template",
side_effect=ChatTemplateResolutionError("No template"),
),
):
full_prompt, engine_prompt = get_score_prompt(
llm_reranker_model_config, # use_pad_token=False
cross_encoder_tokenizer,
tokenization_kwargs,
"query",
"document",
)
assert full_prompt == "querydocument"
assert "prompt_token_ids" in engine_prompt
assert_prompt_tokenization_consistent(
cross_encoder_tokenizer, full_prompt, engine_prompt
)
def test_post_process_tokens_called(
self,
cross_encoder_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
mock_model_with_score_template,
):
"""Test that post_process_tokens is called on the engine prompt."""
# Reset the call tracker
mock_model_with_score_template.post_process_called.clear()
with (
patch(
"vllm.model_executor.model_loader.get_model_cls",
return_value=mock_model_with_score_template,
),
patch(
"vllm.entrypoints.score_utils.apply_hf_chat_template",
side_effect=ChatTemplateResolutionError("No template"),
),
):
full_prompt, engine_prompt = get_score_prompt(
cross_encoder_model_config,
cross_encoder_tokenizer,
tokenization_kwargs,
"query",
"doc",
)
# post_process_tokens should have been called once
assert len(mock_model_with_score_template.post_process_called) == 1
assert mock_model_with_score_template.post_process_called[0] is engine_prompt
assert_prompt_tokenization_consistent(
cross_encoder_tokenizer, full_prompt, engine_prompt
)

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@@ -2,6 +2,7 @@
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import tempfile
from pathlib import Path
import mteb
import numpy as np
@@ -19,6 +20,11 @@ from tests.models.utils import (
get_vllm_extra_kwargs,
)
template_home = (
Path(__file__).parent.parent.parent.parent.parent
/ "examples/pooling/score/template"
)
# Most embedding models on the STS12 task (See #17175):
# - Model implementation and minor changes in tensor dtype
# results in differences less than 1e-4
@@ -102,30 +108,6 @@ class VllmMtebEncoder(mteb.EncoderProtocol):
return sim
class VllmMtebCrossEncoder(mteb.CrossEncoderProtocol):
mteb_model_meta = _empty_model_meta
def __init__(self, vllm_model):
self.llm = vllm_model
self.rng = np.random.default_rng(seed=42)
def predict(
self,
inputs1: DataLoader[mteb.types.BatchedInput],
inputs2: DataLoader[mteb.types.BatchedInput],
*args,
**kwargs,
) -> np.ndarray:
queries = [text for batch in inputs1 for text in batch["text"]]
corpus = [text for batch in inputs2 for text in batch["text"]]
outputs = self.llm.score(
queries, corpus, truncate_prompt_tokens=-1, use_tqdm=False
)
scores = np.array(outputs)
return scores
class OpenAIClientMtebEncoder(VllmMtebEncoder):
def __init__(self, model_name: str, client):
self.model_name = model_name
@@ -153,6 +135,35 @@ class OpenAIClientMtebEncoder(VllmMtebEncoder):
return embeds
class VllmMtebCrossEncoder(mteb.CrossEncoderProtocol):
mteb_model_meta = _empty_model_meta
def __init__(self, vllm_model):
self.llm = vllm_model
self.rng = np.random.default_rng(seed=42)
self.chat_template: str | None = getattr(vllm_model, "chat_template", None)
def predict(
self,
inputs1: DataLoader[mteb.types.BatchedInput],
inputs2: DataLoader[mteb.types.BatchedInput],
*args,
**kwargs,
) -> np.ndarray:
queries = [text for batch in inputs1 for text in batch["text"]]
corpus = [text for batch in inputs2 for text in batch["text"]]
outputs = self.llm.score(
queries,
corpus,
truncate_prompt_tokens=-1,
use_tqdm=False,
chat_template=self.chat_template,
)
scores = np.array(outputs)
return scores
class ScoreClientMtebEncoder(mteb.CrossEncoderProtocol):
mteb_model_meta = _empty_model_meta
@@ -387,6 +398,11 @@ def mteb_test_rerank_models(
== model_info.default_pooling_type
)
chat_template: str | None = None
if model_info.chat_template_name is not None:
chat_template = (template_home / model_info.chat_template_name).read_text()
vllm_model.chat_template = chat_template
vllm_main_score = run_mteb_rerank(
vllm_mteb_encoder(vllm_model),
tasks=MTEB_RERANK_TASKS,

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@@ -0,0 +1,42 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import pytest
from tests.models.utils import (
EmbedModelInfo,
LASTPoolingEmbedModelInfo,
LASTPoolingRerankModelInfo,
RerankModelInfo,
)
from .mteb_utils import mteb_test_embed_models, mteb_test_rerank_models
EMBEDDING_MODELS = [
LASTPoolingEmbedModelInfo(
"nvidia/llama-nemotron-embed-1b-v2",
architecture="LlamaBidirectionalModel",
mteb_score=0.689164662128673,
)
]
RERANK_MODELS = [
LASTPoolingRerankModelInfo(
"nvidia/llama-nemotron-rerank-1b-v2",
architecture="LlamaBidirectionalForSequenceClassification",
chat_template_name="nemotron-rerank.jinja",
mteb_score=0.33994,
),
]
@pytest.mark.parametrize("model_info", EMBEDDING_MODELS)
def test_embed_models_mteb(hf_runner, vllm_runner, model_info: EmbedModelInfo) -> None:
mteb_test_embed_models(hf_runner, vllm_runner, model_info)
@pytest.mark.parametrize("model_info", RERANK_MODELS)
def test_rerank_models_mteb(
hf_runner, vllm_runner, model_info: RerankModelInfo
) -> None:
mteb_test_rerank_models(hf_runner, vllm_runner, model_info)

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@@ -488,6 +488,9 @@ _EMBEDDING_EXAMPLE_MODELS = {
),
"JambaForSequenceClassification": _HfExamplesInfo("ai21labs/Jamba-tiny-reward-dev"),
"LlamaModel": _HfExamplesInfo("llama", is_available_online=False),
"LlamaBidirectionalModel": _HfExamplesInfo(
"nvidia/llama-nemotron-embed-1b-v2", trust_remote_code=True
),
"MistralModel": _HfExamplesInfo("intfloat/e5-mistral-7b-instruct"),
"ModernBertModel": _HfExamplesInfo(
"Alibaba-NLP/gte-modernbert-base", trust_remote_code=True
@@ -554,6 +557,9 @@ _SEQUENCE_CLASSIFICATION_EXAMPLE_MODELS = {
trust_remote_code=True,
hf_overrides={"architectures": ["GteNewForSequenceClassification"]},
),
"LlamaBidirectionalForSequenceClassification": _HfExamplesInfo(
"nvidia/llama-nemotron-rerank-1b-v2", trust_remote_code=True
),
"ModernBertForSequenceClassification": _HfExamplesInfo(
"Alibaba-NLP/gte-reranker-modernbert-base"
),

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@@ -399,6 +399,7 @@ class LASTPoolingEmbedModelInfo(EmbedModelInfo):
@dataclass
class RerankModelInfo(ModelInfo):
mteb_score: float | None = None
chat_template_name: str | None = None
@dataclass