When determining which fields are read-only, ModelAdmin._changeform_view calls ModelAdmin.has_change_permission(request) without the object parameter - so, even if the user has read-only permission, only fields returned by get_readonly_fields() are included. However, subsequent calls to has_change_permission to build the form do use the object parameter - so, all fields are left out of the form, with the assumption that they are included in get_readonly_fields(). This leads to a traceback when rendering the template, since none of the fields are present in the form. (The traceback is included below.)
Changing has_change_permission(request) to has_change_permission(request, obj) on line 1580 of django/contrib/admin/options.py resolves the issue.
Request Method: GET
Request URL: http://localhost:8000/admin/.../.../.../change/
Django Version: 2.1a1
Python Version: 3.6.5
Template error:
In template .../django/contrib/admin/templates/admin/includes/fieldset.html, error at line 7
Key 'full_name' not found in 'UserForm'. Choices are: .
1 : <fieldset class="module aligned {{ fieldset.classes }}">
2 : {% if fieldset.name %}<h2>{{ fieldset.name }}</h2>{% endif %}
3 : {% if fieldset.description %}
4 : <div class="description">{{ fieldset.description|safe }}</div>
5 : {% endif %}
6 : {% for line in fieldset %}
7 : <div class="form-row{% if line.fields|length_is:'1' and line.errors %} errors{% endif %}{% if not line.has_visible_field %} hidden{% endif %} {% for field in line %} {% if field.field.name %} field-{{ field.field.name }}{% endif %}{% endfor %}">
8 : {% if line.fields|length_is:'1' %}{{ line.errors }}{% endif %}
9 : {% for field in line %}
10 : <div{% if not line.fields|length_is:'1' %} class="fieldBox{% if field.field.name %} field-{{ field.field.name }}{% endif %}{% if not field.is_readonly and field.errors %} errors{% endif %}{% if field.field.is_hidden %} hidden{% endif %}"{% elif field.is_checkbox %} class="checkbox-row"{% endif %}>
11 : {% if not line.fields|length_is:'1' and not field.is_readonly %}{{ field.errors }}{% endif %}
12 : {% if field.is_checkbox %}
13 : {{ field.field }}{{ field.label_tag }}
14 : {% else %}
15 : {{ field.label_tag }}
16 : {% if field.is_readonly %}
17 : <div class="readonly">{{ field.contents }}</div>
Traceback:
File ".../django/forms/forms.py" in __getitem__
163. field = self.fields[name]
During handling of the above exception ('full_name'), another exception occurred:
...
File ".../django/template/base.py" in render_annotated
904. return self.render(context)
File ".../django/template/defaulttags.py" in render
165. values = list(values)
File ".../django/contrib/admin/helpers.py" in __iter__
118. yield AdminField(self.form, field, is_first=(i == 0))
File ".../django/contrib/admin/helpers.py" in __init__
130. self.field = form[field] # A django.forms.BoundField instance
File ".../django/forms/forms.py" in __getitem__
169. ', '.join(sorted(f for f in self.fields)),
Exception Type: KeyError
Exception Value: "Key 'full_name' not found in 'UserForm'. Choices are: ."
Paulo, are you able to complete this before Monday's beta release?