Form validation should check for IOErrors

[Stavros Korokithakis]

Forms currently break on various types of images when PIL raises an IOError exception. This should be handled as a form error instead of crashing Django. A traceback is below:

File "main/views.py", line 244, in ad_create_category

if form.is_valid() and image_formset.is_valid():

File "lib/python2.6/site-packages/django/forms/formsets.py", line 237, in is_valid

if bool(self.errors[i]):

File "lib/python2.6/site-packages/django/forms/formsets.py", line 211, in _get_errors

self.full_clean()

File "lib/python2.6/site-packages/django/forms/formsets.py", line 250, in full_clean

self._errors.append(form.errors)

File "lib/python2.6/site-packages/django/forms/forms.py", line 111, in _get_errors

self.full_clean()

File "lib/python2.6/site-packages/django/forms/forms.py", line 238, in full_clean

value = field.clean(value, initial)

File "lib/python2.6/site-packages/django/forms/fields.py", line 511, in clean

trial_image.load()

File "lib/python2.6/site-packages/PIL/ImageFile.py", line 155, in load

self.load_prepare()

File "lib/python2.6/site-packages/PIL/PngImagePlugin.py", line 337, in load_prepare

raise IOError("cannot read interlaced PNG files")

[Honza Král]

can you provide a test for that? or just a file that results in this error? Looking through the code that shouldn't happen:

        except Exception: # Python Imaging Library doesn't recognize it as an image
            raise ValidationError(self.error_messages['invalid_image'])

I am closing it as works for me, feel free to reopen it if you find a file that results in this error. Thanks!

[Stavros Korokithakis]

Sadly, I've searched high and low for such a file, but none of my users has responded. Looking at your code it is indeed miraculous that this happens, but looking at mine elucidates the situation:

    def clean(self, data, initial=None):
        ...
        # load() is the only method that can spot a truncated JPEG,
        #  but it cannot be called sanely after verify()
        trial_image = Image.open(file)
        trial_image.load()

There's no exception block to be found there. I assume it was added after 1.1?

[Honza Král]

No, the try: except: block is present in the 1.1 tarball, just checked just to be sure.

[Stavros Korokithakis]

That's odd, I checked my home install and it has it, but both production and staging don't, and django.VERSION reports 1.1.0 there. This is positively strange, but I upgraded and everything is fine now, thank you.