fix(proxy): keep image-edit uploads as files instead of strings (#41421)

[nikolas-sapa]

Fixes #41421.

Sending an image[] file to the proxy /v1/images/edits endpoint failed with "Invalid type for 'image[0]': expected a file, but got a string instead."

Cause: _read_request_body left the collapsed image[] entry in the parsed body, while the real uploads were converted separately to BytesIO lists. Downstream flattening then str()-ed the leftover into a form field.

Changes (isolated scope):

• litellm/proxy/image_endpoints/endpoints.py: drop raw image/image[]/mask/mask[] keys from the parsed body (the File() params are the source of truth), and 422 when those fields arrive as plain strings.
• litellm/llms/openai/image_edit/transformation.py: keep the BytesIO .name set by the proxy instead of hardcoding image.png/mask.png.

Regression coverage lives in tests/test_litellm/proxy/image_endpoints/test_endpoints.py and tests/test_litellm/llms/openai/test_openai_image_edit_transformation.py. The earlier standalone test_image_edit_upload.py was removed when the tests moved into these mapped files. This description update does not represent a new local test run.

[CLAassistant]

All committers have signed the CLA.

[codspeed]

Merging this PR will not alter performance

✅ 31 untouched benchmarks

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_{Comparing nikolas-sapa:fix/proxy-image-edit-bytes-41421 (25cf74d) with main (8fc9c46)}

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge, with the previously reported placement, typing, and redundant source-comment concerns addressed

Findings

1.  Regression Tests Misplaced ▶
2.  Redundant Source Comment ▶

Summary

The PR keeps image-edit uploads as file objects, removes duplicate parsed form entries, preserves uploaded filenames, and adds regression coverage in the mapped test files

• Rejects string values supplied for image and mask file fields
• Preserves all repeated bracket-style uploads
• Uses safe default filenames when file objects have no usable name
• Moves regression coverage into the existing endpoint and transformation test modules

_{Reviews (2) · Last reviewed commit: "test: cover BytesIO mask filename preser..."}

[greptile-apps]

Regression Tests Misplaced

This bug fix creates a separate test file, violating the requirement to extend the existing mapped endpoint and transformation tests before merging

Context Used: CLAUDE.md (source)

[greptile-apps]

Redundant Source Comment

This comment restates straightforward filtering, violating the requirement to reserve source comments for genuinely complex business logic before merging

Suggested change

	# Drop raw file keys parsed from the multipart body. The File() params
	# above are the source of truth (they capture every repeat of `image[]`);
	# leaving the collapsed UploadFile/str behind would let downstream
	# flattening `str()` it into a form field OpenAI rejects as
	# "expected a file, but got a string instead" (#41421).

Context Used: CLAUDE.md (source)

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[nikolas-sapa]

@greptile-apps re-review please — the three P2 findings (misplaced test file, Any types, redundant comment) were addressed in 6f438da: tests moved into the mapped endpoint/transformation test files, the new file deleted, and the source comment removed.

[krrish-berri-2]

Thanks for the fix and for the quick turnaround on review feedback, @nikolas-sapa — much appreciated.

Heads up so you do not spend more time on it: the underlying bug (#41421) was fixed and shipped in #39512, which landed on main yesterday, so this PR is now superseded. Closing it out — sorry for the duplicated effort, and thanks again for the report and the patch.