From d43156e1e984d7e0848b7d4db218877a29d617b4 Mon Sep 17 00:00:00 2001
From: Claude Paroz <claude@2xlibre.net>
Date: Sat, 20 Feb 2016 14:40:07 +0100
Subject: [PATCH] Fixed #26238 -- Raised explicit error for non-editable field
 in ModelForm

Thanks Luke Crouch for the report and Simon Charette for the review.
---
 django/forms/models.py     |  6 ++++++
 docs/ref/models/fields.txt |  3 ++-
 tests/model_forms/tests.py | 15 +++++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/django/forms/models.py b/django/forms/models.py
index 8e8c8cfb55..be9e63d144 100644
--- a/django/forms/models.py
+++ b/django/forms/models.py
@@ -148,6 +148,12 @@ def fields_for_model(model, fields=None, exclude=None, widgets=None,
                                if isinstance(f, ModelField)]
     for f in sorted(chain(opts.concrete_fields, sortable_virtual_fields, opts.many_to_many)):
         if not getattr(f, 'editable', False):
+            if (fields is not None and f.name in fields and
+                    (exclude is None or f.name not in exclude)):
+                raise FieldError(
+                    "'%s' cannot be specified for %s model form as it is a non-editable field" % (
+                        f.name, model.__name__)
+                )
             continue
         if fields is not None and f.name not in fields:
             continue
diff --git a/docs/ref/models/fields.txt b/docs/ref/models/fields.txt
index 4a1c9eefbb..de493dda67 100644
--- a/docs/ref/models/fields.txt
+++ b/docs/ref/models/fields.txt
@@ -415,7 +415,8 @@ guaranteed to fit numbers from ``-9223372036854775808`` to
 
 A field to store raw binary data. It only supports ``bytes`` assignment. Be
 aware that this field has limited functionality. For example, it is not possible
-to filter a queryset on a ``BinaryField`` value.
+to filter a queryset on a ``BinaryField`` value. It is also not possible to
+include a ``BinaryField`` in a :class:`~django.forms.ModelForm`.
 
 .. admonition:: Abusing ``BinaryField``
 
diff --git a/tests/model_forms/tests.py b/tests/model_forms/tests.py
index 968407e845..a2e7c66419 100644
--- a/tests/model_forms/tests.py
+++ b/tests/model_forms/tests.py
@@ -2282,6 +2282,21 @@ class ModelOtherFieldTests(SimpleTestCase):
         self.assertTrue(HomepageForm({'url': 'http://www.example.com:8000/test'}).is_valid())
         self.assertTrue(HomepageForm({'url': 'http://example.com/foo/bar'}).is_valid())
 
+    def test_modelform_non_editable_field(self):
+        """
+        When explicitely including a non-editable field in a ModelForm, the
+        error message should be explicit.
+        """
+        # 'created', non-editable, is excluded by default
+        self.assertNotIn('created', ArticleForm().fields)
+
+        msg = "'created' cannot be specified for Article model form as it is a non-editable field"
+        with self.assertRaisesMessage(FieldError, msg):
+            class InvalidArticleForm(forms.ModelForm):
+                class Meta:
+                    model = Article
+                    fields = ('headline', 'created')
+
     def test_http_prefixing(self):
         """
         If the http:// prefix is omitted on form input, the field adds it again. (Refs #13613)