UnboundLocalError in PIL/JpegImagePlugin.py

[Deanamic]

What did you do?

Run the Pytorch transfer Learning tutorial

What did you expect to happen?

The code executes correctly

What actually happened?

an unboundlocalerror ocurred

File "/home/.../.venv/lib/python3.7/site-packages/torch/utils/data/dataloader.py", line 138, in _worker_loop 
samples = collate_fn([dataset[i] for i in batch_indices])
File "/home/.../.venv/lib/python3.7/site-packages/torch/utils/data/dataloader.py", line 138, in <listcomp>
samples = collate_fn([dataset[i] for i in batch_indices])
File "/home/.../.venv/lib/python3.7/site-packages/torchvision/datasets/folder.py", line 132, in __getitem__
 sample = self.loader(path)
File "/home/.../.venv/lib/python3.7/site-packages/torchvision/datasets/folder.py", line 178, in default_loader
 return pil_loader(path)
File "/home/.../.venv/lib/python3.7/site-packages/torchvision/datasets/folder.py", line 160, in pil_loader
 img = Image.open(f)
File "/home/.../.venv/lib/python3.7/site-packages/PIL/Image.py", line 2690, in open
 im = _open_core(fp, filename, prefix)
File "/home/.../.venv/lib/python3.7/site-packages/PIL/Image.py", line 2676, in _open_core
 im = factory(fp, filename)
File "/home/.../.venv/lib/python3.7/site-packages/PIL/JpegImagePlugin.py", line 783, in jpeg_factory
 im = JpegImageFile(fp, filename)
File "/home/.../.venv/lib/python3.7/site-packages/PIL/ImageFile.py", line 103, in __init__
 self._open()
File "/home/.../.venv/lib/python3.7/site-packages/PIL/JpegImagePlugin.py", line 373, in _open                
handler(self, i)
File "/home/.../TransferLearning-Torch/.venv/lib/python3.7/site-packages/PIL/JpegImagePlugin.py", line 139, in APP
 self.info["photoshop"] = photoshop
UnboundLocalError: local variable 'photoshop' referenced before assignment

What are your OS, Python and Pillow versions?

• OS: Manjaro Linux
• Python: 3.7.3
• Pillow: 6.0.0

I can consistently reproduce this by running the script on the tutorial above. The issue doesn't occur if I downgrade to Pillow 5.4.1

[radarhere]

Thanks for reporting this. I've created PR #3771 to resolve it.

[Emma0928]

Thank you for sharing this solution.
How can I downgrade my pillow version?

[hugovk]

Downgrade with something like pip install "pillow==x.y.z" where x.y.z is the version you want.

[Emma0928]

Downgrade with something like pip install "pillow==x.y.z" where x.y.z is the version you want.

Thank you for your reply!! It worked~