WebPImagePlugin.py - ResourceWarning: unclosed file

[pajadam]

What did you do?

> python -Wd
Python 3.7.0 (default, Jul 15 2018, 10:44:58)
[GCC 8.1.1 20180531] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from PIL import Image
>>> with Image.open('tshirt.webp') as img:
...     img.save('tshirt.png', 'PNG')
...
/home/pajadam/.venv/hype/lib/python3.7/site-packages/PIL/WebPImagePlugin.py:156: ResourceWarning: unclosed file <_io.BufferedReader name='tshirt.webp'>
  self.fp = BytesIO(data)
>>>

What did you expect to happen?

No warnings, especially while using context manager.

What actually happened?

Following warning occurs:

/home/pajadam/.venv/hype/lib/python3.7/site-packages/PIL/WebPImagePlugin.py:156: ResourceWarning: unclosed file <_io.BufferedReader name='tshirt.webp'>
  self.fp = BytesIO(data)

What versions of Pillow and Python are you using?

• Pillow==5.2
• Python 3.7

Minimal example:

from PIL import Image

with Image.open('tshirt.webp') as img:
     img.save('tshirt.png', 'PNG')

[radarhere]

Thanks for reporting this. This can be replicated using transparent.webp from the Pillow test images.

I have created PR #3341

[hugovk]

Re-opening as #3341 caused an error and was reverted in #3415.

[radarhere]

I have created PR #3418 as a revised solution to this.