fix(scheduler): reject non-positive max_num_scheduled_tokens at construction time#44125
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…ruction time The `<= 0` guard on `SchedulerConfig.max_num_scheduled_tokens` exists in `VllmConfig._set_max_num_scheduled_tokens` but is gated behind `speculative_config is not None`, so without speculative decoding a negative value survives construction, propagates through `Scheduler.__init__` (the truthiness fallback at scheduler.py:104 treats negatives as truthy), and trips a bare `assert token_budget >= 0` inside `schedule()`. Match the sibling `max_num_batched_tokens` field by adding `Field(default=None, ge=1)` so non-positive values are rejected at field validation regardless of speculative-decoding mode. The post_init `<= 0` guard remains for the derived-value path (max_num_batched_tokens minus the draft-token delta), which is computed inside the method and not subject to field validation. Fixes vllm-project#44123 Signed-off-by: Chenglun Hu <chenglunhu@gmail.com>
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…vents configs Add @field_validator decorators to reject invalid configuration values at construction time, preventing silent failures and confusing errors. - flash_attn_max_num_splits_for_cuda_graph: reject non-positive values - tq_max_kv_splits_for_cuda_graph: reject non-positive values - flex_attn_block_m, flex_attn_block_n: validate >= 16 and power of 2 - flex_attn_q_block_size, flex_attn_kv_block_size: validate power of 2 - buffer_steps: reject non-positive values - hwm: reject non-positive values - max_queue_size: reject non-positive values - kv_buffer_size: reject non-positive values - kv_rank: reject negative values when set - kv_parallel_size: reject non-positive values - kv_port: validate port range [1, 65535] - ec_buffer_size: reject non-positive values - ec_rank: reject negative values when set - ec_parallel_size: reject non-positive values - ec_port: validate port range [1, 65535] These fields currently accept invalid values that downstream code doesn't expect, leading to: - Silent no-ops (negative values ignored by conditionals) - Runtime errors with confusing messages - Undefined behavior Pattern follows recent PRs: vllm-project#43794, vllm-project#44002, vllm-project#44070, vllm-project#44093, vllm-project#44125 All validators use mode='after' with clear error messages following project conventions. Signed-off-by: Joinal Ahmed <jahmed@redhat.com>
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Fixes #44123
The
<= 0guard onSchedulerConfig.max_num_scheduled_tokensexists inVllmConfig._set_max_num_scheduled_tokensbut is gated behindspeculative_config is not None. Without speculative decoding a negative value survives construction, propagates throughScheduler.__init__(truthiness fallback atscheduler.py:104treats negatives as truthy), and trips a bareassert token_budget >= 0insideschedule().This matches the sibling
max_num_batched_tokensfield by addingField(default=None, ge=1)— non-positive values rejected at field validation regardless of speculative-decoding mode. The post_init<= 0guard stays for the derived-value path (max_num_batched_tokens - scheduled_token_deltacomputed inside the method).Before
After
(Repro from the verbatim test in #44123; standalone pydantic verification above.)
Test
Adds 4 assertions to
test_scheduler_config_initintests/test_config.pycovering None / positive / 0 / negative.