Fixed #20649 -- Allowed blank field display to be defined in the initial list of choices.

AUTHORS

@@ -161,6 +161,7 @@ answer newbie questions, and generally made Django that much better:
     Paul Collier <paul@paul-collier.com>
     Paul Collins <paul.collins.iii@gmail.com>
     Robert Coup
+    Alex Couper <http://alexcouper.com/>
     Deric Crago <deric.crago@gmail.com>
     Brian Fabian Crain <http://www.bfc.do/>
     David Cramer <dcramer@gmail.com>

django/db/models/fields/__init__.py

@@ -544,7 +544,14 @@ class Field(object):
     def get_choices(self, include_blank=True, blank_choice=BLANK_CHOICE_DASH):
         """Returns choices with a default blank choices included, for use
         as SelectField choices for this field."""
-        first_choice = blank_choice if include_blank else []
+        blank_defined = False
+        for choice, _ in self.choices:
+            if choice in ('', None):
+                blank_defined = True
+                break
+
+        first_choice = (blank_choice if include_blank and
+                        not blank_defined else [])
         if self.choices:
             return first_choice + list(self.choices)
         rel_model = self.rel.to

django/forms/widgets.py

@@ -511,6 +511,8 @@ class Select(Widget):
         return mark_safe('\n'.join(output))
 
     def render_option(self, selected_choices, option_value, option_label):
+        if option_value == None:
+            option_value = ''
         option_value = force_text(option_value)
         if option_value in selected_choices:
             selected_html = mark_safe(' selected="selected"')

docs/ref/models/fields.txt

@@ -152,11 +152,20 @@ method to retrieve the human-readable name for the field's current value. See
 :meth:`~django.db.models.Model.get_FOO_display` in the database API
 documentation.
 
-Finally, note that choices can be any iterable object -- not necessarily a list
+Note that choices can be any iterable object -- not necessarily a list or tuple.
-or tuple. This lets you construct choices dynamically. But if you find yourself
+This lets you construct choices dynamically. But if you find yourself hacking
-hacking :attr:`~Field.choices` to be dynamic, you're probably better off using a
+:attr:`~Field.choices` to be dynamic, you're probably better off using a proper
-proper database table with a :class:`ForeignKey`. :attr:`~Field.choices` is
+database table with a :class:`ForeignKey`. :attr:`~Field.choices` is meant for
-meant for static data that doesn't change much, if ever.
+static data that doesn't change much, if ever.
+
+.. versionadded:: 1.7
+
+Unless :attr:`blank=False<Field.blank>` is set on the field along with a
+:attr:`~Field.default` then a label containing ``"---------"`` will be rendered
+with the select box. To override this behavior, add a tuple to ``choices``
+containing ``None``; e.g. ``(None, 'Your String For Display')``.
+Alternatively, you can use an empty string instead of ``None`` where this makes
+sense - such as on a :class:`~django.db.models.CharField`.
 
 ``db_column``
 -------------

docs/releases/1.7.txt

@@ -105,6 +105,11 @@ Minor features
   <django.contrib.auth.forms.AuthenticationForm.confirm_login_allowed>` method
   to more easily customize the login policy.
 
+* :attr:`Field.choices<django.db.models.Field.choices>` now allows you to
+  customize the "empty choice" label by including a tuple with an empty string
+  or ``None`` for the key and the custom label as the value. The default blank
+  option ``"----------"`` will be omitted in this case.
+
 Backwards incompatible changes in 1.7
 =====================================
 

tests/forms_tests/models.py

@@ -34,7 +34,30 @@ class Defaults(models.Model):
 
 class ChoiceModel(models.Model):
     """For ModelChoiceField and ModelMultipleChoiceField tests."""
+    CHOICES = [
+        ('', 'No Preference'),
+        ('f', 'Foo'),
+        ('b', 'Bar'),
+    ]
+
+    INTEGER_CHOICES = [
+        (None, 'No Preference'),
+        (1, 'Foo'),
+        (2, 'Bar'),
+    ]
+
+    STRING_CHOICES_WITH_NONE = [
+        (None, 'No Preference'),
+        ('f', 'Foo'),
+        ('b', 'Bar'),
+    ]
+
     name = models.CharField(max_length=10)
+    choice = models.CharField(max_length=2, blank=True, choices=CHOICES)
+    choice_string_w_none = models.CharField(
+        max_length=2, blank=True, null=True, choices=STRING_CHOICES_WITH_NONE)
+    choice_integer = models.IntegerField(choices=INTEGER_CHOICES, blank=True,
+                                         null=True)
 
 
 @python_2_unicode_compatible

tests/forms_tests/tests/tests.py

@@ -10,8 +10,8 @@ from django.forms.models import ModelFormMetaclass
 from django.test import TestCase
 from django.utils import six
 
-from ..models import (ChoiceOptionModel, ChoiceFieldModel, FileModel, Group,
+from ..models import (ChoiceModel, ChoiceOptionModel, ChoiceFieldModel,
-    BoundaryModel, Defaults, OptionalMultiChoiceModel)
+    FileModel, Group, BoundaryModel, Defaults, OptionalMultiChoiceModel)
 
 
 class ChoiceFieldForm(ModelForm):
@@ -34,6 +34,24 @@ class ChoiceFieldExclusionForm(ModelForm):
         model = ChoiceFieldModel
 
 
+class EmptyCharLabelChoiceForm(ModelForm):
+    class Meta:
+        model = ChoiceModel
+        fields = ['name', 'choice']
+
+
+class EmptyIntegerLabelChoiceForm(ModelForm):
+    class Meta:
+        model = ChoiceModel
+        fields = ['name', 'choice_integer']
+
+
+class EmptyCharLabelNoneChoiceForm(ModelForm):
+    class Meta:
+        model = ChoiceModel
+        fields = ['name', 'choice_string_w_none']
+
+
 class FileForm(Form):
     file1 = FileField()
 
@@ -259,3 +277,78 @@ class ManyToManyExclusionTestCase(TestCase):
         self.assertEqual(form.instance.choice_int.pk, data['choice_int'])
         self.assertEqual(list(form.instance.multi_choice.all()), [opt2, opt3])
         self.assertEqual([obj.pk for obj in form.instance.multi_choice_int.all()], data['multi_choice_int'])
+
+
+class EmptyLabelTestCase(TestCase):
+    def test_empty_field_char(self):
+        f = EmptyCharLabelChoiceForm()
+        self.assertHTMLEqual(f.as_p(),
+            """<p><label for="id_name">Name:</label> <input id="id_name" maxlength="10" name="name" type="text" /></p>
+<p><label for="id_choice">Choice:</label> <select id="id_choice" name="choice">
+<option value="" selected="selected">No Preference</option>
+<option value="f">Foo</option>
+<option value="b">Bar</option>
+</select></p>""")
+
+    def test_empty_field_char_none(self):
+        f = EmptyCharLabelNoneChoiceForm()
+        self.assertHTMLEqual(f.as_p(),
+            """<p><label for="id_name">Name:</label> <input id="id_name" maxlength="10" name="name" type="text" /></p>
+<p><label for="id_choice_string_w_none">Choice string w none:</label> <select id="id_choice_string_w_none" name="choice_string_w_none">
+<option value="" selected="selected">No Preference</option>
+<option value="f">Foo</option>
+<option value="b">Bar</option>
+</select></p>""")
+
+    def test_save_empty_label_forms(self):
+        # Test that saving a form with a blank choice results in the expected
+        # value being stored in the database.
+        tests = [
+            (EmptyCharLabelNoneChoiceForm, 'choice_string_w_none', None),
+            (EmptyIntegerLabelChoiceForm, 'choice_integer', None),
+            (EmptyCharLabelChoiceForm, 'choice', ''),
+        ]
+
+        for form, key, expected in tests:
+            f = form({'name': 'some-key', key: ''})
+            self.assertTrue(f.is_valid())
+            m = f.save()
+            self.assertEqual(expected, getattr(m, key))
+            self.assertEqual('No Preference',
+                             getattr(m, 'get_{0}_display'.format(key))())
+
+    def test_empty_field_integer(self):
+        f = EmptyIntegerLabelChoiceForm()
+        self.assertHTMLEqual(f.as_p(),
+            """<p><label for="id_name">Name:</label> <input id="id_name" maxlength="10" name="name" type="text" /></p>
+<p><label for="id_choice_integer">Choice integer:</label> <select id="id_choice_integer" name="choice_integer">
+<option value="" selected="selected">No Preference</option>
+<option value="1">Foo</option>
+<option value="2">Bar</option>
+</select></p>""")
+
+    def test_get_display_value_on_none(self):
+        m = ChoiceModel.objects.create(name='test', choice='', choice_integer=None)
+        self.assertEqual(None, m.choice_integer)
+        self.assertEqual('No Preference', m.get_choice_integer_display())
+
+    def test_html_rendering_of_prepopulated_models(self):
+        none_model = ChoiceModel(name='none-test', choice_integer=None)
+        f = EmptyIntegerLabelChoiceForm(instance=none_model)
+        self.assertHTMLEqual(f.as_p(),
+            """<p><label for="id_name">Name:</label> <input id="id_name" maxlength="10" name="name" type="text" value="none-test"/></p>
+<p><label for="id_choice_integer">Choice integer:</label> <select id="id_choice_integer" name="choice_integer">
+<option value="" selected="selected">No Preference</option>
+<option value="1">Foo</option>
+<option value="2">Bar</option>
+</select></p>""")
+
+        foo_model = ChoiceModel(name='foo-test', choice_integer=1)
+        f = EmptyIntegerLabelChoiceForm(instance=foo_model)
+        self.assertHTMLEqual(f.as_p(),
+            """<p><label for="id_name">Name:</label> <input id="id_name" maxlength="10" name="name" type="text" value="foo-test"/></p>
+<p><label for="id_choice_integer">Choice integer:</label> <select id="id_choice_integer" name="choice_integer">
+<option value="">No Preference</option>
+<option value="1" selected="selected">Foo</option>
+<option value="2">Bar</option>
+</select></p>""")

tests/model_fields/tests.py

@@ -331,6 +331,10 @@ class ValidationTest(test.TestCase):
         f = models.CharField(choices=[('a', 'A'), ('b', 'B')])
         self.assertRaises(ValidationError, f.clean, "not a", None)
 
+    def test_charfield_get_choices_with_blank_defined(self):
+        f = models.CharField(choices=[('', '<><>'), ('a', 'A')])
+        self.assertEqual(f.get_choices(True), [('', '<><>'), ('a', 'A')])
+
     def test_choices_validation_supports_named_groups(self):
         f = models.IntegerField(
             choices=(('group', ((10, 'A'), (20, 'B'))), (30, 'C')))