Django TypeError: render() got an unexpected keyword argument 'renderer'

Question

I've upgraded to Django 2.1, and I'm seeing this error when I load the admin interface:

TypeError at /admin/foo/bar/1/change/

render() got an unexpected keyword argument 'renderer'

Answer 1

This is almost certainly because of this backwards-incompatible change in Django 2.1:

• Support for Widget.render() methods without the renderer argument is removed.

You may have subclassed django.forms.widgets.Widget in your code, or in the code of one of your dependencies. The code may look like this:

from django.forms import widgets

class ExampleWidget(widgets.Widget):
    def render(self, name, value, attrs=None):
        # ...

You need to fix the method signature of render, so that it looks like this:

    def render(self, name, value, attrs=None, renderer=None):

Have a look at the source code of widgets.Widget if you want to check.