tiff file handle is closed too early

[db4]

Suppose I have a TIFF file with 2 pages. I do

tiff = Image.open('file.tif')
tiff.seek(0)
tiff.load()
tiff.seek(1)
tiff.load()

this somehow triggers the tiff handle closing:

# TiffImagePlugin.py, line 1077
        # libtiff closed the fp in a, we need to close self.fp, if possible
        if hasattr(self.fp, 'close'):
            if not self.__next:
                self.fp.close()

and subsequent

tiff.seek(0)

will fail with ValueError: seek of closed file
I tried to fix this in 30dc185 but this was not enough. So I hope someone familiar with the code will fix it correctly.

[wiredfool]

Does this happen with any of the existing multi page tiff images that we're shipping as tests, or is there a different tiff to use as a test case which would expose this?

[db4]

My impression is that we need an additional test file. You can find it here together with a test case: 25804cc

[sekrause]

The file descriptor handling with multipage TIFFs is actually quite messed up, see my realted issue #1651 and especially my latest comment there: #1651 (comment)

So we have both the problems of self.fd being closed too early and at the same time dangling duplicated file descriptiors which are not being closed at any time.

The solution should probably look like this:

• Only close self.fd when the image file is being closed.
• Only create duplicate file descriptors when we need to pass a file descriptors into libtiff (because libtiff closes the file handles passed to it).

[radarhere]

Using https://github.com/python-pillow/Pillow/blob/25804cc8c753eb542f66310c0ef6fefff99d97ab/Tests/images/compression2.tif?raw=true and testing, this looks like it was fixed by #2330