Fixed #10349 -- Modified ManyToManyFields to allow initial form values to be callables. Thanks to fas for the report and patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10652 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/related.py

@@ -948,7 +948,10 @@ class ManyToManyField(RelatedField, Field):
         # If initial is passed in, it's a list of related objects, but the
         # MultipleChoiceField takes a list of IDs.
         if defaults.get('initial') is not None:
-            defaults['initial'] = [i._get_pk_val() for i in defaults['initial']]
+            initial = defaults['initial']
+            if callable(initial):
+                initial = initial()
+            defaults['initial'] = [i._get_pk_val() for i in initial]
         return super(ManyToManyField, self).formfield(**defaults)
 
     def db_type(self):

tests/modeltests/model_forms/models.py

@@ -613,6 +613,30 @@ Add some categories and test the many-to-many form output.
 <option value="3">Third test</option>
 </select>  Hold down "Control", or "Command" on a Mac, to select more than one.</li>
 
+Initial values can be provided for model forms
+>>> f = TestArticleForm(auto_id=False, initial={'headline': 'Your headline here', 'categories': ['1','2']})
+>>> print f.as_ul()
+<li>Headline: <input type="text" name="headline" value="Your headline here" maxlength="50" /></li>
+<li>Slug: <input type="text" name="slug" maxlength="50" /></li>
+<li>Pub date: <input type="text" name="pub_date" /></li>
+<li>Writer: <select name="writer">
+<option value="" selected="selected">---------</option>
+<option value="1">Mike Royko</option>
+<option value="2">Bob Woodward</option>
+</select></li>
+<li>Article: <textarea rows="10" cols="40" name="article"></textarea></li>
+<li>Status: <select name="status">
+<option value="" selected="selected">---------</option>
+<option value="1">Draft</option>
+<option value="2">Pending</option>
+<option value="3">Live</option>
+</select></li>
+<li>Categories: <select multiple="multiple" name="categories">
+<option value="1" selected="selected">Entertainment</option>
+<option value="2" selected="selected">It&#39;s a test</option>
+<option value="3">Third test</option>
+</select>  Hold down "Control", or "Command" on a Mac, to select more than one.</li>
+
 >>> f = TestArticleForm({'headline': u'New headline', 'slug': u'new-headline', 'pub_date': u'1988-01-04',
 ...     'writer': u'1', 'article': u'Hello.', 'categories': [u'1', u'2']}, instance=new_art)
 >>> new_art = f.save()

tests/regressiontests/forms/forms.py

@@ -1146,37 +1146,63 @@ possible to specify callable data.
 >>> class UserRegistration(Form):
 ...    username = CharField(max_length=10)
 ...    password = CharField(widget=PasswordInput)
+...    options = MultipleChoiceField(choices=[('f','foo'),('b','bar'),('w','whiz')])
 
 We need to define functions that get called later.
 >>> def initial_django():
 ...     return 'django'
 >>> def initial_stephane():
 ...     return 'stephane'
+>>> def initial_options():
+...     return ['f','b']
+>>> def initial_other_options():
+...     return ['b','w']
+
 
 Here, we're not submitting any data, so the initial value will be displayed.
->>> p = UserRegistration(initial={'username': initial_django}, auto_id=False)
+>>> p = UserRegistration(initial={'username': initial_django, 'options': initial_options}, auto_id=False)
 >>> print p.as_ul()
 <li>Username: <input type="text" name="username" value="django" maxlength="10" /></li>
 <li>Password: <input type="password" name="password" /></li>
+<li>Options: <select multiple="multiple" name="options">
+<option value="f" selected="selected">foo</option>
+<option value="b" selected="selected">bar</option>
+<option value="w">whiz</option>
+</select></li>
 
 The 'initial' parameter is meaningless if you pass data.
->>> p = UserRegistration({}, initial={'username': initial_django}, auto_id=False)
+>>> p = UserRegistration({}, initial={'username': initial_django, 'options': initial_options}, auto_id=False)
 >>> print p.as_ul()
 <li><ul class="errorlist"><li>This field is required.</li></ul>Username: <input type="text" name="username" maxlength="10" /></li>
 <li><ul class="errorlist"><li>This field is required.</li></ul>Password: <input type="password" name="password" /></li>
+<li><ul class="errorlist"><li>This field is required.</li></ul>Options: <select multiple="multiple" name="options">
+<option value="f">foo</option>
+<option value="b">bar</option>
+<option value="w">whiz</option>
+</select></li>
 >>> p = UserRegistration({'username': u''}, initial={'username': initial_django}, auto_id=False)
 >>> print p.as_ul()
 <li><ul class="errorlist"><li>This field is required.</li></ul>Username: <input type="text" name="username" maxlength="10" /></li>
 <li><ul class="errorlist"><li>This field is required.</li></ul>Password: <input type="password" name="password" /></li>
->>> p = UserRegistration({'username': u'foo'}, initial={'username': initial_django}, auto_id=False)
+<li><ul class="errorlist"><li>This field is required.</li></ul>Options: <select multiple="multiple" name="options">
+<option value="f">foo</option>
+<option value="b">bar</option>
+<option value="w">whiz</option>
+</select></li>
+>>> p = UserRegistration({'username': u'foo', 'options':['f','b']}, initial={'username': initial_django}, auto_id=False)
 >>> print p.as_ul()
 <li>Username: <input type="text" name="username" value="foo" maxlength="10" /></li>
 <li><ul class="errorlist"><li>This field is required.</li></ul>Password: <input type="password" name="password" /></li>
+<li>Options: <select multiple="multiple" name="options">
+<option value="f" selected="selected">foo</option>
+<option value="b" selected="selected">bar</option>
+<option value="w">whiz</option>
+</select></li>
 
 A callable 'initial' value is *not* used as a fallback if data is not provided.
 In this example, we don't provide a value for 'username', and the form raises a
 validation error rather than using the initial value for 'username'.
->>> p = UserRegistration({'password': 'secret'}, initial={'username': initial_django})
+>>> p = UserRegistration({'password': 'secret'}, initial={'username': initial_django, 'options': initial_options})
 >>> p.errors['username']
 [u'This field is required.']
 >>> p.is_valid()
@@ -1187,14 +1213,26 @@ then the latter will get precedence.
 >>> class UserRegistration(Form):
 ...    username = CharField(max_length=10, initial=initial_django)
 ...    password = CharField(widget=PasswordInput)
+...    options = MultipleChoiceField(choices=[('f','foo'),('b','bar'),('w','whiz')], initial=initial_other_options)
+
 >>> p = UserRegistration(auto_id=False)
 >>> print p.as_ul()
 <li>Username: <input type="text" name="username" value="django" maxlength="10" /></li>
 <li>Password: <input type="password" name="password" /></li>
->>> p = UserRegistration(initial={'username': initial_stephane}, auto_id=False)
+<li>Options: <select multiple="multiple" name="options">
+<option value="f">foo</option>
+<option value="b" selected="selected">bar</option>
+<option value="w" selected="selected">whiz</option>
+</select></li>
+>>> p = UserRegistration(initial={'username': initial_stephane, 'options': initial_options}, auto_id=False)
 >>> print p.as_ul()
 <li>Username: <input type="text" name="username" value="stephane" maxlength="10" /></li>
 <li>Password: <input type="password" name="password" /></li>
+<li>Options: <select multiple="multiple" name="options">
+<option value="f" selected="selected">foo</option>
+<option value="b" selected="selected">bar</option>
+<option value="w">whiz</option>
+</select></li>
 
 # Help text ###################################################################
 

tests/regressiontests/model_forms_regress/models.py

@@ -14,3 +14,17 @@ class Triple(models.Model):
 
 class FilePathModel(models.Model):
     path = models.FilePathField(path=os.path.dirname(__file__), match=".*\.py$", blank=True)
+
+class Publication(models.Model):
+    title = models.CharField(max_length=30)
+    date = models.DateField()
+
+    def __unicode__(self):
+        return self.title
+
+class Article(models.Model):
+    headline = models.CharField(max_length=100)
+    publications = models.ManyToManyField(Publication)
+
+    def __unicode__(self):
+        return self.headline

tests/regressiontests/model_forms_regress/tests.py

@@ -1,8 +1,12 @@
+from datetime import date
+
 from django import db
 from django import forms
+from django.forms.models import modelform_factory
 from django.conf import settings
 from django.test import TestCase
-from models import Person, Triple, FilePathModel
+
+from models import Person, Triple, FilePathModel, Article, Publication
 
 class ModelMultipleChoiceFieldTests(TestCase):
 
@@ -59,3 +63,30 @@ class FilePathFieldTests(TestCase):
         names = [p[1] for p in form['path'].field.choices]
         names.sort()
         self.assertEqual(names, ['---------', '__init__.py', 'models.py', 'tests.py'])
+
+class ManyToManyCallableInitialTests(TestCase):
+    def test_callable(self):
+        "Regression for #10349: A callable can be provided as the initial value for an m2m field"
+
+        # Set up a callable initial value
+        def formfield_for_dbfield(db_field, **kwargs):
+            if db_field.name == 'publications':
+                kwargs['initial'] = lambda: Publication.objects.all().order_by('date')[:2]
+            return db_field.formfield(**kwargs)
+
+        # Set up some Publications to use as data
+        Publication(title="First Book", date=date(2007,1,1)).save()
+        Publication(title="Second Book", date=date(2008,1,1)).save()
+        Publication(title="Third Book", date=date(2009,1,1)).save()
+
+        # Create a ModelForm, instantiate it, and check that the output is as expected
+        ModelForm = modelform_factory(Article, formfield_callback=formfield_for_dbfield)
+        form = ModelForm()
+        self.assertEquals(form.as_ul(), u"""<li><label for="id_headline">Headline:</label> <input id="id_headline" type="text" name="headline" maxlength="100" /></li>
+<li><label for="id_publications">Publications:</label> <select multiple="multiple" name="publications" id="id_publications">
+<option value="1" selected="selected">First Book</option>
+<option value="2" selected="selected">Second Book</option>
+<option value="3">Third Book</option>
+</select>  Hold down "Control", or "Command" on a Mac, to select more than one.</li>""")
+
+