OSError: [Errno 24] Too many open files for image.save for tiff images

[gooseillo]

What did you do?
I am opening a large number of jpg and tiff (single page & multi page) images, resizing them and saving them in a new directory. I am running this code within VS code in jupyter notebook using PIL 9.0.0

    def change_image_res(rep_image, 
                        new_path,
                        max_image_thresh=49, 
                        percent_reduce_res = [0.1, 0.2, 0.3, 0.4, 0.5]):

    image_name = rep_image.name
    save_all = True if rep_image.suffix == '.tiff' else False

    new_path = Path(new_path)

    with open(rep_image, "rb") as f:
        image = Image.open(f)
    
        if (image.size[0]*image.size[1])/1000000 > max_image_thresh:
            for res in percent_reduce_res:
                fixed_height = int(int((float(image.size[1]))) - (res * int((float(image.size[1])))))
                height_percent = (fixed_height / float(image.size[1]))
                width_size = int((float(image.size[0]) * float(height_percent)))
                if fixed_height*width_size/1000000 < 50:
                    image = image.resize((width_size, fixed_height), PIL.Image.NEAREST)
                    image.save(f'{new_path}\{image_name}', dpi=(300,300), save_all=save_all)
                    break
        else:
            image.save(f'{new_path}\{image_name}', dpi=(300,300), save_all=save_all)

What did you expect to happen?
I expected the images to be opened, processed, saved and closed automatically because of the context manager.

What actually happened?

After opening over a thousand images I get the following error

OSError: [Errno 24] Too many open files

I also notice that the python.exe instance builds up around 5GB ram. Restarting the Kernel releases the memory

I have tried every thing possible on the internet like temp copy, deep copy, using close(), using load() etc.
I have also tried every thing in this issue

#2760

[radarhere]

If you didn't have the context manager, I would suggest calling image.close - https://pillow.readthedocs.io/en/stable/releasenotes/7.0.0.html#image-del

But you do, so that makes things more interesting.

Is there any way for you to provide us with a self-contained example including images, so that we can run the code and see the error for ourselves?

[gooseillo]

self_contained_test.zip

I tried it without the context manager along with image.close but got the same error

In the folder which I have attached, I ran python change_img_res.py. After 1014 loops, it gives the following error

[radarhere]

The zip you've attached is empty?

[gooseillo]

Apologies, I updated the attachment.

[radarhere]

Thanks. I was able to replicate the error using your attachment - radarhere@031dae421260 / https://ci.appveyor.com/project/radarhere/pillow/builds/42132497/job/qnvpmk4ougrx4x6l

I've concluded that the problem is because of this

Pillow/src/PIL/TiffImagePlugin.py

Lines 1186 to 1188 in eff6c34

	# libtiff closes the file descriptor, so pass in a dup.
	try:
	fp = hasattr(self.fp, "fileno") and os.dup(self.fp.fileno())

Perhaps libtiff doesn't always close the file pointer?

If I ensure that it is closed, then the CI job passes.

So I've created PR #5946 to resolve this.

[gooseillo]

Thanks for this, the new change solves this problem.

[radarhere]

Be aware that #7199 has been opened, using an alternative method to fix this.