litellm_fix(hosted_vllm): use custom client when provided

[shin-bot-litellm]

Summary

Fixes failing CI tests for hosted_vllm provider:

• test_openai_compatible_custom_api_video[hosted_vllm]
• test_openai_compatible_custom_api_base[hosted_vllm]

Root Cause

PR #19893 added a dedicated hosted_vllm branch in main.py that routes all requests through base_llm_http_handler.completion() to support ssl_verify. However, this broke the behavior when a custom OpenAI client is passed - the client was ignored because base_llm_http_handler uses its own httpx client internally.

Fix

When a custom client parameter is provided:

• Use openai_chat_completions.completion() which properly utilizes the passed client
• This ensures the client is used correctly (e.g., for mocking in tests)

When no custom client is provided:

• Continue using base_llm_http_handler.completion() to preserve the ssl_verify functionality from fix(hosted_vllm): route through base_llm_http_handler to support ssl_verify #19893

Testing

Both failing tests now pass:

tests/local_testing/test_completion.py::test_openai_compatible_custom_api_base[hosted_vllm] PASSED
tests/local_testing/test_completion.py::test_openai_compatible_custom_api_video[hosted_vllm] PASSED

The ssl_verify tests from #19893 still pass:

tests/test_litellm/llms/hosted_vllm/chat/test_hosted_vllm_ssl_verify.py::TestHostedVLLMSSLVerify::test_hosted_vllm_ssl_verify_false_async PASSED
tests/test_litellm/llms/hosted_vllm/chat/test_hosted_vllm_ssl_verify.py::TestHostedVLLMSSLVerify::test_hosted_vllm_ssl_verify_false_sync PASSED

CircleCI Link

https://app.circleci.com/pipelines/github/BerriAI/litellm/56610/workflows/ddae19f6-881e-49e1-922e-005927a11564/jobs/1135770/tests

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Project	Deployment	Actions	Updated (UTC)
litellm	Error		Jan 31, 2026 6:01pm

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