fix(openai): repair the annotation that makes litellm unimportable

[yassin-berriai]

TLDR

Problem this solves:

• import litellm raises NameError: name 'Union' is not defined
• litellm_internal_staging is red on every open PR
• ruff check reports F821 at llms/openai/common_utils.py:138

How it solves it:

• Rewrites the annotation as a PEP 604 union

Relevant issues

Linear ticket

Pre-Submission checklist

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• I have added meaningful tests
• My PR passes all CI/CD checks (e.g., lint, format, unit tests)
• My PR's scope is as isolated as possible; it only solves 1 specific problem
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Delays in PR merge?

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Screenshots / Proof of Fix

Both runs are a plain import litellm against a worktree at the named commit, nothing mocked

$ git log --oneline -1
9d5984b358 refactor(ui): rename the create MCP server component to PascalCase (#35686)

$ python -c "import litellm; print('import ok')"
  File ".../litellm/llms/openai/common_utils.py", line 138, in BaseOpenAILLM
    def owns_wrapped_http_client(http_client: Optional[Union[httpx.Client, httpx.AsyncClient]]) -> bool:
                                                       ^^^^^
NameError: name 'Union' is not defined

$ git log --oneline -1
<this PR's head>

$ python -c "import litellm.llms.openai.common_utils as m; import httpx; print(m.BaseOpenAILLM.owns_wrapped_http_client(None), m.BaseOpenAILLM.owns_wrapped_http_client(httpx.Client()))"
True True

$ cd litellm && ruff check .
All checks passed!

Before the fix, cd litellm && ruff check . (the lint job's exact command) reports:

F821 Undefined name `Union`
   --> llms/openai/common_utils.py:138:56
Found 1 error.

Type

🐛 Bug Fix

Changes

BaseOpenAILLM.owns_wrapped_http_client annotates its parameter with Optional[Union[httpx.Client, httpx.AsyncClient]], but Union was never added to the module's typing import. The annotation is evaluated when the class body executes, so the NameError fires at import rather than at call time, and every module that imports litellm dies with it.

The annotation becomes httpx.Client | httpx.AsyncClient | None rather than gaining a Union import. requires-python is >=3.10, so PEP 604 unions evaluate at runtime, and both UP007 and UP045 sit at a ceiling of 0 in ruff-strict-budget.json, so adding the import would have traded the F821 for a budget failure. That is not hypothetical: the first push of this branch did exactly that and the lint job went red on UP007: total 67 over limit 0 (this change added 1).

That is why lint and the entire test matrix are failing on open PRs whose diffs contain no Python: CI evaluates the PR merged into the current staging tip, so staging's breakage is attributed to each PR.

No test is added. The regression is "the package imports at all", which every existing test in the suite already asserts as a precondition; the whole matrix going from red to green is the assertion.

Final Attestation

• The tests check the right things, including the edge cases, and regressions in the respective real-world customer use-cases are not possible after this PR

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[greptile-apps]

Greptile Summary

This PR restores LiteLLM importability by replacing an annotation that references the missing Union name with supported PEP 604 syntax.

• Updates BaseOpenAILLM.owns_wrapped_http_client to accept sync clients, async clients, or None using |.
• Preserves the annotation’s existing type semantics while avoiding the import-time NameError.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
litellm/llms/openai/common_utils.py	Replaces the undefined Union reference with an equivalent annotation supported by the package’s Python 3.10+ runtime requirement.

_{Reviews (2): Last reviewed commit: "fix(openai): repair the annotation that ..." | Re-trigger Greptile}

[yassin-berriai]

@greptileai please review the current head 256f1ec

The 5/5 above is pinned to cc81916, which was force-pushed away. That commit added Union to the typing import and traded the F821 for a lint failure on UP007: total 67 over limit 0, since UP007 and UP045 both sit at a ceiling of 0. The head instead rewrites the annotation as httpx.Client | httpx.AsyncClient | None; requires-python is >=3.10 so the PEP 604 union evaluates at runtime, and the strict-rule gate passes locally against the current base.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[codspeed-hq]

Merging this PR will not alter performance

✅ 31 untouched benchmarks

---

_{Comparing litellm_fix_openai_common_utils_union (256f1ec) with litellm_internal_staging (7c8364c)¹}

Footnotes

1. No successful run was found on litellm_internal_staging (9d5984b) during the generation of this report, so 7c8364c was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[yassin-berriai]

Superseded by #35706, which landed the identical fix (httpx.Client | httpx.AsyncClient | None rather than a Union import, for the same UP007/UP045 ceiling reason) and also covers a second call site in openai.py that this PR missed. Staging imports again; closing.