[Bugfix] Register VLLM_BATCH_INVARIANT in envs.py to fix spurious unknown env var warning

[WindChimeRan]

Purpose

Register VLLM_BATCH_INVARIANT in envs.py to suppress spurious warning.

VLLM_BATCH_INVARIANT is read via os.getenv() in batch_invariant.py but is never registered in envs.py's environment_variables dict. This causes validate_environ() to emit an "Unknown vLLM environment variable detected" warning every time the feature is used:

WARNING 02-20 23:18:09 [envs.py:1656] Unknown vLLM environment variable detected: VLLM_BATCH_INVARIANT

This PR adds the env var to both the type stub and the registry dict in envs.py.

Test Plan

import os
os.environ["VLLM_BATCH_INVARIANT"] = "1"

from vllm import LLM, SamplingParams

llm = LLM(
    model="Qwen/Qwen3-0.6B",
    max_model_len=128,
    attention_config={"backend": "FLASH_ATTN"},
)
print(llm.generate(["Hello"], SamplingParams(temperature=0, max_tokens=5))[0].outputs[0].text)

Verify no "Unknown vLLM environment variable" warning is emitted.

Test Result

Before: warning is emitted on every invocation with VLLM_BATCH_INVARIANT set.

WARNING 02-20 23:18:09 [envs.py:1656] Unknown vLLM environment variable detected: VLLM_BATCH_INVARIANT

After: no warning.

---

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[dosubot]

Related Documentation

Checked 0 published document(s) in 1 knowledge base(s). No updates required.

^{How did I do? Any feedback?}  

[gemini-code-assist]

Code Review

The pull request correctly registers the VLLM_BATCH_INVARIANT environment variable in vllm/envs.py to suppress the 'Unknown vLLM environment variable' warning. This is a necessary step for maintaining a clean log output when this feature is used. However, the implementation of the boolean conversion for this variable is less robust than the one it replaces in batch_invariant.py and could lead to a crash if a non-integer value (like 'true') is provided. Additionally, there is now duplicated logic for reading this environment variable between envs.py and batch_invariant.py, which should ideally be consolidated if circular dependencies can be avoided.

[gemini-code-assist]

The current implementation using int() will raise a ValueError and crash the application if the environment variable is set to a non-integer value such as "true" or "false". This is a regression in robustness compared to the original implementation in batch_invariant.py which handled this error gracefully. It is recommended to use a more robust parsing pattern consistent with other variables in this file (e.g., VLLM_USE_PRECOMPILED).

Suggested change

	"VLLM_BATCH_INVARIANT": lambda: bool(
	int(os.getenv("VLLM_BATCH_INVARIANT", "0"))
	),
	"VLLM_BATCH_INVARIANT": lambda: os.getenv("VLLM_BATCH_INVARIANT", "0")
	.strip()
	.lower()
	in ("1", "true"),

[WindChimeRan]

I think this is overcomplicating things. my style is consistent with other envs. So it should be fine.

[mergify]

Hi @WindChimeRan, the pre-commit checks have failed. Please run:

uv pip install pre-commit
pre-commit install
pre-commit run --all-files

Then, commit the changes and push to your branch.

For future commits, pre-commit will run automatically on changed files before each commit.

Tip

Is mypy or markdownlint failing?

mypy and markdownlint are run differently in CI. If the failure is related to either of these checks, please use the following commands to run them locally:

# For mypy (substitute "3.10" with the failing version if needed)
pre-commit run --hook-stage manual mypy-3.10
# For markdownlint
pre-commit run --hook-stage manual markdownlint

[yewentao256]

Thanks for the work! The idea looks good

Please update the logic in _read_vllm_batch_invariant and related usage

[yewentao256]

Please solve the pre-commit issue so that we can land this pr

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @WindChimeRan.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[WindChimeRan]

@yewentao256 All green!