Fix get_filename_list crash when a cached model folder is deleted

[JSap0914]

Bug

get_filename_list() crashes with FileNotFoundError when a model
folder that was present at cache-build time is deleted while ComfyUI is
running.

cached_filename_list_() validates the cache by comparing the stored
mtime of every directory recorded during the previous scan
(recursive_search records each subfolder's mtime, not just the
top-level roots). It does this with a bare os.path.getmtime(folder).
If any tracked folder has since been removed, getmtime() raises
FileNotFoundError, which propagates out of get_filename_list() and
breaks model listing for that category — instead of just invalidating
the stale cache and rebuilding it.

Repro:

import os, shutil, tempfile, folder_paths

base = tempfile.mkdtemp()
cat = os.path.join(base, "category"); sub = os.path.join(cat, "sub")
os.makedirs(sub)
open(os.path.join(cat, "a.safetensors"), "w").close()
open(os.path.join(sub, "b.safetensors"), "w").close()
folder_paths.folder_names_and_paths["demo"] = ([cat], {".safetensors"})

folder_paths.get_filename_list("demo")   # builds cache, records sub/ mtime
shutil.rmtree(sub)                         # folder removed at runtime
folder_paths.get_filename_list("demo")   # -> FileNotFoundError

Fix

Treat an inaccessible tracked folder as a stale-cache signal: catch
OSError around the getmtime probe and return None, so the cache is
rebuilt rather than raising. This mirrors the existing behaviour when a
folder's mtime simply changed.

Verification

$ python -m pytest tests-unit/folder_paths_test/ -v
...
35 passed in 0.14s

The suite includes a new regression test
(tests-unit/folder_paths_test/cache_invalidation_test.py) that builds
the cache, deletes a tracked subfolder, and asserts the next
get_filename_list() call rebuilds successfully instead of crashing. It
fails on master and passes with this change.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Fixes folder_paths filename cache invalidation when a previously tracked subfolder is deleted, and adds a regression test to ensure the cache rebuilds instead of raising during mtime checks.

Changes:

• Treat missing/inaccessible tracked folders as a stale cache condition during cache validation.
• Add a unit test that deletes a tracked subfolder and verifies get_filename_list() rebuilds correctly.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
tests-unit/folder_paths_test/cache_invalidation_test.py	Adds regression coverage for deleting a tracked subfolder after cache population.
folder_paths.py	Updates cache validation to handle deleted/inaccessible tracked folders without raising.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: a1aa4b96-7f83-4642-9100-3deffa32ccf9

📥 Commits

Reviewing files that changed from the base of the PR and between 5db51b7 and fe89d39.

📒 Files selected for processing (2)

• folder_paths.py
• tests-unit/folder_paths_test/cache_invalidation_test.py

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📝 Walkthrough

Walkthrough

cached_filename_list_ in folder_paths.py now wraps its per-folder os.path.getmtime comparison in a try/except OSError. When a tracked folder has been deleted or becomes inaccessible, the function returns None to signal a stale cache instead of allowing the error to propagate. A new test file adds a model_folder pytest fixture that registers a temporary tracked subfolder and cleans up afterward, plus a regression test that primes the cache, deletes the subfolder, and confirms the next get_filename_list call rebuilds cleanly.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main fix: preventing a crash in get_filename_list when a cached model folder is deleted.
Description check	✅ Passed	The description comprehensively explains the bug, the fix, and includes verification with a reproduction case and test results.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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