Describe the bug

diffusers.utils.load_video() creates a temporary file using NamedTemporaryFile(delete=False) when downloading a video from a URL. However, the temporary file is removed only after video decoding completes successfully.

If decoding raises an exception (for example, when attempting to load a corrupted GIF), execution never reaches the cleanup statement, leaving the downloaded file on disk.

Repeated failures may accumulate unnecessary temporary files.

Steps to reproduce

The following reproduction uses a mocked HTTP response and requires no GPU or external network access.

import os
import tempfile
from unittest.mock import patch

from PIL import UnidentifiedImageError
from diffusers.utils import load_video


class FakeResponse:
    status_code = 200

    def iter_content(self, chunk_size=8192):
        yield b"THIS_IS_NOT_A_VALID_GIF"


with tempfile.TemporaryDirectory() as tmp_dir:
    with (
        patch(
            "diffusers.utils.loading_utils.requests.get",
            return_value=FakeResponse(),
        ),
        patch(
            "diffusers.utils.loading_utils.tempfile.tempdir",
            tmp_dir,
        ),
    ):
        try:
            load_video("https://example.com/corrupt.gif")
        except UnidentifiedImageError as e:
            print(type(e).__name__, str(e))

        print("Remaining files:", os.listdir(tmp_dir))

Actual behavior

The decoder raises UnidentifiedImageError, but the temporary file remains on disk.

Observed output:

Exception: UnidentifiedImageError

Remaining temporary files:
tmpeiv6c3cc.gif | Size: 23 bytes

BUG REPRODUCED: Temporary file was not deleted!

Expected behavior

Temporary files created for remote video downloads should be deleted even when downloading or decoding fails. The original exception should continue to propagate.

Root cause

In src/diffusers/utils/loading_utils.py:

• Line 97 creates a temporary file with delete=False.
• The subsequent code downloads and decodes the video.
• Line 142 removes the temporary file only after successful decoding.

Any exception before the cleanup statement bypasses file deletion.

Proposed fix

Ensure exception-safe cleanup of downloaded temporary files using try/finally, covering both download and decoding failures.

Add regression tests verifying that temporary files are removed on both successful and failed operations.

Environment

• Repository: huggingface/diffusers
• Source revision reproduced: 899c9f3
• OS: Windows
• Device: CPU
• Reproduction: mocked HTTP response with corrupted GIF content
• No pretrained models required

Who can help?

@sayakpaul @yiyixuxu

I would appreciate your review and any suggestions regarding exception-safe temporary-file cleanup and regression test coverage in load_video().