Cannot update ImageField to a new image file (Wagtail 1.3.1, Python 3.4.4)

When I initially save an image to an ImageField that is a subclass of Page the image is properly saved. An update to that image sets the ImageField’s path to an invalid path and doesn’t upload the file.

Steps to reproduce:

wagtail start image_field_test
cd image_field_test/

Change home/model.py definition to :

from __future__ import unicode_literals
from django.db import models
from wagtail.wagtailcore.models import Page
from wagtail.wagtailadmin.edit_handlers import FieldPanel

class HomePage(Page):
    image = models.ImageField(upload_to='uploaded_images', default='')

    content_panels = Page.content_panels + [
        FieldPanel('image'),
    ]

mkdir -p media/uploaded_images
chmod -R 777 media
python manage.py makemigrations
python manage.py migrate
python manage.py createsuperuser
python manage.py runserver

• Log into the admin interface and navigate to the home page (currently http://127.0.0.1:8000/admin/pages/3/edit/).
• Add an image and publish
• Go back to the page and notice how the image path is missing the uploaded_images prefix and clicking on the link goes nowhere. The file is also not present in the file system.
• When creating a new home page I can add an image once. On update I get the problem detailed above.

[mx-moth]

I’ve tracked down the issue to some code in django-modelcluster. I’ve fixed it there, created a PR (torchbox/django-modelcluster#53), and started a PR (#2422) to fix it in Wagtail once the django-modelcluster issue is fixed. Thanks for your bug reports!

[gasman]

Fixed in #2422 (and more specifically https://github.com/torchbox/django-modelcluster/pull/53)