Horizontal fieldset breaks in admin and api browser when read_only is False for nested serializers

[mcastle]

There's no error for json. And this doesn't happen for every serializer with a nested serializer - it seems to occur only when the nested serializer itself has a nested serializer. This is using django rest framework version 3.3.1. Here's the traceback:

Environment:


Request Method: GET
Request URL: http://127.0.0.1:8000/api/endpoints/3/

Django Version: 1.8.7
Python Version: 2.7.10

Template error:
In template /Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/templates/rest_framework/horizontal/fieldset.html, error at line 13
   'unicode' object has no attribute 'items'

   3 :   {% if field.label %}
   4 :     <div class="form-group" style="border-bottom: 1px solid #e5e5e5">
   5 :       <legend class="control-label col-sm-2 {% if style.hide_label %}sr-only{% endif %}" style="border-bottom: 0">
   6 :         {{ field.label }}
   7 :       </legend>
   8 :     </div>
   9 :   {% endif %}
   10 : 
   11 :   {% for nested_field in field %}
   12 :     {% if not nested_field.read_only %}
   13 :        {% render_field nested_field style=style %} 
   14 :     {% endif %}
   15 :   {% endfor %}
   16 : </fieldset>
   17 : 

Traceback:
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  164.                 response = response.render()
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/response.py" in render
  158.             self.content = self.rendered_content
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/response.py" in rendered_content
  71.         ret = renderer.render(self.data, media_type, context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/renderers.py" in render
  711.         context = self.get_context(data, accepted_media_type, renderer_context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/renderers.py" in get_context
  738.             data, accepted_media_type, renderer_context
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/renderers.py" in get_context
  648.             'put_form': self.get_rendered_html_form(data, view, 'PUT', request),
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/renderers.py" in get_rendered_html_form
  499.                 {'style': {'template_pack': 'rest_framework/horizontal'}}
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/renderers.py" in render
  357.         return template.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/backends/django.py" in render
  74.         return self.template.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  210.                     return self._render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/test/utils.py" in instrumented_test_render
  96.     return self.nodelist.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  905.                 bit = self.render_node(node, context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/debug.py" in render_node
  79.             return node.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  217.                             nodelist.append(node.render(context))
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  329.                 return nodelist.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  905.                 bit = self.render_node(node, context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/debug.py" in render_node
  79.             return node.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  1197.                     return func(*resolved_args, **resolved_kwargs)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/templatetags/rest_framework.py" in render_field
  37.     return renderer.render_field(field, style)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/renderers.py" in render_field
  337.         return template.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/backends/django.py" in render
  74.         return self.template.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  210.                     return self._render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/test/utils.py" in instrumented_test_render
  96.     return self.nodelist.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  905.                 bit = self.render_node(node, context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/debug.py" in render_node
  79.             return node.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  217.                             nodelist.append(node.render(context))
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  329.                 return nodelist.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  905.                 bit = self.render_node(node, context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/debug.py" in render_node
  79.             return node.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  1197.                     return func(*resolved_args, **resolved_kwargs)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/templatetags/rest_framework.py" in render_field
  37.     return renderer.render_field(field, style)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/renderers.py" in render_field
  337.         return template.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/backends/django.py" in render
  74.         return self.template.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  210.                     return self._render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/test/utils.py" in instrumented_test_render
  96.     return self.nodelist.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  905.                 bit = self.render_node(node, context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/debug.py" in render_node
  79.             return node.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  217.                             nodelist.append(node.render(context))
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  329.                 return nodelist.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  905.                 bit = self.render_node(node, context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/debug.py" in render_node
  79.             return node.render(context)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/django/template/base.py" in render
  1197.                     return func(*resolved_args, **resolved_kwargs)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/templatetags/rest_framework.py" in render_field
  37.     return renderer.render_field(field, style)
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/renderers.py" in render_field
  325.         field = field.as_form_field()
File "/Users/user/virtualenvs/ddrsite/lib/python2.7/site-packages/rest_framework/utils/serializer_helpers.py" in as_form_field
  111.         for key, value in self.value.items():

Exception Type: AttributeError at /api/endpoints/3/
Exception Value: 'unicode' object has no attribute 'items'

[xordoquy]

@mcastle do you have a code sample we could use to reproduce the issue ?

[hellraider01]

how it resolve the error? i have the same problem and in my case we will try to list a one "comment" from a list of comment. The model have ManyToManyField called comments. And the serializer of comment have the attribute many=True. Why append this?

[hellraider01]

i forgot, the Traceback is exactly the same.

[hellraider01]

the serializres inside the classes that use is: comments = CommentSerializer(many=True, read_only=True)

[mcastle]

Fixed by #4473.

[tomchristie]

Thanks for the update @mcastle!

[mcastle]

For sure!