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[Core][V0] Enable regex support with xgrammar (#13228)

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Signed-off-by: Russell Bryant <rbryant@redhat.com>
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Russell Bryant 2025-04-13 22:13:38 -04:00 committed by GitHub
parent 63d2705edb
commit dc1b4a6f13
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GPG Key ID: B5690EEEBB952194
3 changed files with 25 additions and 9 deletions
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15
tests/entrypoints/llm/test_guided_generate.py
View File

@ -286,15 +286,26 @@ def test_validation_against_both_guided_decoding_options(sample_regex, llm):
@pytest.mark.skip_global_cleanup
def test_disable_guided_decoding_fallback(sample_regex, llm):
# see has_xgrammar_unsupported_json_features()
unsupported_json = {
"type": "object",
"properties": {
"example": {
"type": "string",
"minLength": 5 # unsupported by xgrammar
}
}
}
sampling_params = SamplingParams(temperature=0.8,
top_p=0.95,
guided_decoding=GuidedDecodingParams(
regex=sample_regex,
json=unsupported_json,
backend="xgrammar:no-fallback"))
with pytest.raises(
ValueError,
match="xgrammar does not support regex guided decoding"):
match="xgrammar does not support advanced JSON schema features "
"like enums, patterns or numeric ranges."):
llm.generate(prompts="This should fail",
sampling_params=sampling_params,
use_tqdm=True)

9
vllm/model_executor/guided_decoding/__init__.py
View File

@ -59,14 +59,9 @@ def maybe_backend_fallback(
from vllm.model_executor.guided_decoding.xgrammar_decoding import (
xgr_installed)
# xgrammar doesn't support regex, fallback to outlines
if guided_params.regex is not None:
fallback_or_error(
guided_params,
"xgrammar does not support regex guided decoding.", "outlines")
# xgrammar doesn't support some JSON schema features
elif (guided_params.json is not None
and has_xgrammar_unsupported_json_features(guided_params.json)):
if (guided_params.json is not None and
has_xgrammar_unsupported_json_features(guided_params.json)):
fallback_or_error(
guided_params,
"xgrammar does not support advanced JSON schema features like "

10
vllm/model_executor/guided_decoding/xgrammar_decoding.py
View File

@ -152,6 +152,7 @@ class GrammarConfig:
grammar_str: str | None = None
json_object: bool | None = None
any_whitespace: bool = True
regex_str: str | None = None
max_threads: int = 8
@classmethod
@ -255,6 +256,13 @@ class GrammarConfig:
max_threads=max_threads,
tokenizer_data=tokenizer_data,
)
elif guided_params.regex:
return cls(
regex_str=guided_params.regex,
tokenizer_hash=tokenizer_hash,
max_threads=max_threads,
tokenizer_data=tokenizer_data,
)
else:
raise ValueError(
"Currently only support JSON and EBNF grammar mode for xgrammar"
@ -330,6 +338,8 @@ class XGrammarLogitsProcessor:
self.ctx = compiler\
.compile_json_schema('{"type": "object"}',
any_whitespace=any_whitespace)
elif self.config.regex_str:
self.ctx = compiler.compile_regex(self.config.regex_str)
else:
raise ValueError(
"Invalid configuration for xgrammar logits processor")