fix(proxy): unwrap nested managed batch output file IDs on retrieve

[Solaris-star]

Summary

• Repeated managed batch retrieve could nest a unified output_file_id / error_file_id inside another unified ID.
• model_mappings then pointed at a managed ID instead of the raw provider file/gs URI, so content download failed.
• Add _unwrap_managed_output_file_id to peel nested managed output IDs, keep the outermost response ID, and always persist the raw provider ID.
• Unit coverage for single-layer no-double-wrap and nested unwrap.

Fixes #33988

Test plan

• pytest managed_files_hook double_wrap / unwrap_nested / skip_non_file / pass_credentials / fallback_when_no_router -> 5 passed
• CI full suite
• Manual: complete managed batch, retrieve twice, confirm model_mappings stay raw provider IDs and file content still downloads

[CLAassistant]

All committers have signed the CLA.

[greptile-apps]

Greptile Summary

This PR makes repeated managed batch retrieval preserve raw provider file IDs. The main changes are:

• Adds recursive unwrapping for nested managed output and error file IDs
• Keeps the outer unified ID in batch responses
• Stores the raw provider ID in model mappings
• Adds focused tests for nested and already-unified IDs

Confidence Score: 4/5

The production ID handling looks correct, but the process-wide test stub needs to be scoped before merging.

• Nested IDs are unwrapped before storing model mappings.
• The response keeps its outer unified ID as intended.
• The module-level sys.modules mutation can break later tests based on worker order.

tests/test_litellm/enterprise/proxy/test_managed_files_hook.py

Important Files Changed

Filename	Overview
enterprise/litellm_enterprise/proxy/hooks/managed_files.py	Adds cycle-aware nested managed-ID unwrapping and persists the resulting raw provider ID.
tests/test_litellm/enterprise/proxy/test_managed_files_hook.py	Adds meaningful retrieval tests but introduces a process-wide proxy-server stub that can leak into other tests.

_{Reviews (1): Last reviewed commit: "fix(proxy): unwrap nested managed batch ..." | Re-trigger Greptile}

[greptile-apps]

Stub Leaks Across Test Modules

This collection-time mutation permanently replaces litellm.proxy.proxy_server in the worker's import cache. Under xdist, later tests in the same worker can receive this stub, which only defines llm_router, and fail when managed-file paths import other real attributes such as scheduler, prisma_client, or user_api_key_cache.

Rule Used: What: Flag any modifications to existing tests and... (source)

[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

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_{Comparing Solaris-star:fix/33988-managed-batch-output-double-wrap (38644aa) with main (5d4c4d0)}