fix(ci): exclude deleted files from ruff format check

[yuneng-berri]

Relevant issues

The "Check ruff format" step in the LiteLLM Linting workflow fails with exit code 123 on any PR that deletes a litellm/**/*.py file. Surfaced on the promote-to-main PR #31384, which removes litellm/ocr/rust_bridge.py:

error: Failed to format litellm/ocr/rust_bridge.py: No such file or directory (os error 2)
301 files already formatted

Type

🐛 Bug Fix

Changes

The step builds its file list with git diff --name-only, which includes deleted paths. The deleted file is then piped to ruff format --check, which cannot format a file that no longer exists on disk and exits 123. Every other file is already correctly formatted; the failure is purely a workflow bug, not a real formatting issue.

The fix adds --diff-filter=ACMR so only added, copied, modified, and renamed files are checked, dropping deletions. This matches the pattern already used in test-litellm-ui-build.yml

Screenshots / Proof of Fix

Local reproduction of the false positive and the fix, against the same base SHA CI used (bd2a1653bd92aeef272b29feaa750706db094975):

Before (current main behavior; lists the deleted file):

$ git diff --name-only "$BASE_SHA"...origin/litellm_internal_staging -- 'litellm/**/*.py' | grep -c '^litellm/ocr/rust_bridge.py$'
1

After (--diff-filter=ACMR; deleted file is gone):

$ git diff --name-only --diff-filter=ACMR "$BASE_SHA"...origin/litellm_internal_staging -- 'litellm/**/*.py' | grep -c '^litellm/ocr/rust_bridge.py$'
0

The CI run for this PR exercises the changed workflow directly, since pull_request runs the workflow from the merge commit

[greptile-apps]

Greptile Summary

This PR fixes a false-positive CI failure in the "Check ruff format" step of the LiteLLM Linting workflow, which would exit with code 123 whenever a PR deleted a litellm/**/*.py file.

• Adds --diff-filter=ACMR to the git diff --name-only call so only Added, Copied, Modified, and Renamed files are piped to ruff format --check, matching the same pattern already used in test-litellm-ui-build.yml.
• The PR includes before/after local reproduction confirming the deleted file is correctly excluded after the fix.

Confidence Score: 5/5

Safe to merge — the change is confined to a single CI workflow line and only affects which files are piped to ruff format --check; it cannot break any production code path.

The one-line fix is clearly correct: git diff without --diff-filter returns deleted paths, which ruff format cannot open, causing an always-failing workflow step. The added filter is already used elsewhere in the repo. No other files are touched.

No files require special attention.

Important Files Changed

Filename	Overview
.github/workflows/test-linting.yml	Adds --diff-filter=ACMR to git diff to exclude deleted files from the ruff format check, fixing a spurious exit-123 failure when a PR removes a Python file.

_{Reviews (1): Last reviewed commit: "fix(ci): exclude deleted files from ruff..." | Re-trigger Greptile}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[mateo-berri]

LGTM; thanks!

Apologies that the new linting caused friction