Fixed #13679, #13231, #7287 -- Ensured that models that have ForeignKeys/ManyToManyField can use a a callable default that returns a model instance/queryset. #13679 was a regression in behavior; the other two tickets are pleasant side effects. Thanks to 3point2 for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13577 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/forms/fields.py

@@ -127,6 +127,9 @@ class Field(object):
 
         self.validators = self.default_validators + validators
 
+    def prepare_value(self, value):
+        return value
+
     def to_python(self, value):
         return value
 

django/forms/forms.py

@@ -18,10 +18,10 @@ __all__ = ('BaseForm', 'Form')
 NON_FIELD_ERRORS = '__all__'
 
 def pretty_name(name):
-    """Converts 'first_name' to 'First name'""" 
-    if not name: 
-        return u'' 
-    return name.replace('_', ' ').capitalize() 
+    """Converts 'first_name' to 'First name'"""
+    if not name:
+        return u''
+    return name.replace('_', ' ').capitalize()
 
 def get_declared_fields(bases, attrs, with_base_fields=True):
     """
@@ -423,6 +423,7 @@ class BoundField(StrAndUnicode):
         """
         if not widget:
             widget = self.field.widget
+
         attrs = attrs or {}
         auto_id = self.auto_id
         if auto_id and 'id' not in attrs and 'id' not in widget.attrs:
@@ -430,6 +431,7 @@ class BoundField(StrAndUnicode):
                 attrs['id'] = auto_id
             else:
                 attrs['id'] = self.html_initial_id
+
         if not self.form.is_bound:
             data = self.form.initial.get(self.name, self.field.initial)
             if callable(data):
@@ -439,6 +441,8 @@ class BoundField(StrAndUnicode):
                 data = self.form.initial.get(self.name, self.field.initial)
             else:
                 data = self.data
+        data = self.field.prepare_value(data)
+
         if not only_initial:
             name = self.html_name
         else:

django/forms/models.py

@@ -906,12 +906,7 @@ class ModelChoiceIterator(object):
         return len(self.queryset)
 
     def choice(self, obj):
-        if self.field.to_field_name:
-            key = obj.serializable_value(self.field.to_field_name)
-        else:
-            key = obj.pk
-        return (key, self.field.label_from_instance(obj))
-
+        return (self.field.prepare_value(obj), self.field.label_from_instance(obj))
 
 class ModelChoiceField(ChoiceField):
     """A ChoiceField whose choices are a model QuerySet."""
@@ -971,8 +966,8 @@ class ModelChoiceField(ChoiceField):
             return self._choices
 
         # Otherwise, execute the QuerySet in self.queryset to determine the
-        # choices dynamically. Return a fresh QuerySetIterator that has not been
-        # consumed. Note that we're instantiating a new QuerySetIterator *each*
+        # choices dynamically. Return a fresh ModelChoiceIterator that has not been
+        # consumed. Note that we're instantiating a new ModelChoiceIterator *each*
         # time _get_choices() is called (and, thus, each time self.choices is
         # accessed) so that we can ensure the QuerySet has not been consumed. This
         # construct might look complicated but it allows for lazy evaluation of
@@ -981,6 +976,14 @@ class ModelChoiceField(ChoiceField):
 
     choices = property(_get_choices, ChoiceField._set_choices)
 
+    def prepare_value(self, value):
+        if hasattr(value, '_meta'):
+            if self.to_field_name:
+                return value.serializable_value(self.to_field_name)
+            else:
+                return value.pk
+        return super(ModelChoiceField, self).prepare_value(value)
+
     def to_python(self, value):
         if value in EMPTY_VALUES:
             return None
@@ -1030,3 +1033,8 @@ class ModelMultipleChoiceField(ModelChoiceField):
             if force_unicode(val) not in pks:
                 raise ValidationError(self.error_messages['invalid_choice'] % val)
         return qs
+
+    def prepare_value(self, value):
+        if hasattr(value, '__iter__'):
+            return [super(ModelMultipleChoiceField, self).prepare_value(v) for v in value]
+        return super(ModelMultipleChoiceField, self).prepare_value(value)

django/forms/widgets.py

@@ -450,13 +450,14 @@ class Select(Widget):
         output.append(u'</select>')
         return mark_safe(u'\n'.join(output))
 
+    def render_option(self, selected_choices, option_value, option_label):
+        option_value = force_unicode(option_value)
+        selected_html = (option_value in selected_choices) and u' selected="selected"' or ''
+        return u'<option value="%s"%s>%s</option>' % (
+            escape(option_value), selected_html,
+            conditional_escape(force_unicode(option_label)))
+
     def render_options(self, choices, selected_choices):
-        def render_option(option_value, option_label):
-            option_value = force_unicode(option_value)
-            selected_html = (option_value in selected_choices) and u' selected="selected"' or ''
-            return u'<option value="%s"%s>%s</option>' % (
-                escape(option_value), selected_html,
-                conditional_escape(force_unicode(option_label)))
         # Normalize to strings.
         selected_choices = set([force_unicode(v) for v in selected_choices])
         output = []
@@ -464,10 +465,10 @@ class Select(Widget):
             if isinstance(option_label, (list, tuple)):
                 output.append(u'<optgroup label="%s">' % escape(force_unicode(option_value)))
                 for option in option_label:
-                    output.append(render_option(*option))
+                    output.append(self.render_option(selected_choices, *option))
                 output.append(u'</optgroup>')
             else:
-                output.append(render_option(option_value, option_label))
+                output.append(self.render_option(selected_choices, option_value, option_label))
         return u'\n'.join(output)
 
 class NullBooleanSelect(Select):