Fixed #9942 -- Added a to_python handler for FloatField to ensure correct typing…

Fixed #9942 -- Added a to_python handler for FloatField to ensure correct typing of deserialized data before saving. Underlying problem is analogous to #8298, fixed in [8515]. Thanks to David Larlet <larlet@gmail.com> for the report and fix.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9695 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -239,6 +239,7 @@ answer newbie questions, and generally made Django that much better:
     Nick Lane <nick.lane.au@gmail.com>
     Stuart Langridge <http://www.kryogenix.org/>
     Paul Lanier <planier@google.com>
+    David Larlet <larlet@gmail.com>
     Nicola Larosa <nico@teknico.net>
     Finn Gruwier Larsen <finn@gruwier.dk>
     Lau Bech Lauritzen

django/db/models/fields/__init__.py

@@ -658,6 +658,15 @@ class FloatField(Field):
     def get_internal_type(self):
         return "FloatField"
 
+    def to_python(self, value):
+        if value is None:
+            return value
+        try:
+            return float(value)
+        except (TypeError, ValueError):
+            raise exceptions.ValidationError(
+                _("This value must be a float."))
+
     def formfield(self, **kwargs):
         defaults = {'form_class': forms.FloatField}
         defaults.update(kwargs)

tests/regressiontests/fixtures_regress/fixtures/animal.xml

@@ -4,5 +4,6 @@
       <field type="CharField" name="name">Emu</field>
       <field type="CharField" name="latin_name">Dromaius novaehollandiae</field>
       <field type="IntegerField" name="count">42</field>
+      <field type="FloatField" name="weight">1.2</field>
   </object>
 </django-objects>
\ No newline at end of file

tests/regressiontests/fixtures_regress/fixtures/sequence.json

@@ -5,7 +5,8 @@
         "fields": {
             "name": "Lion", 
             "latin_name": "Panthera leo",
-            "count": 3
+            "count": 3,
+            "weight": 1.2
         }
     }
 ]
\ No newline at end of file

tests/regressiontests/fixtures_regress/models.py

@@ -7,6 +7,7 @@ class Animal(models.Model):
     name = models.CharField(max_length=150)
     latin_name = models.CharField(max_length=150)
     count = models.IntegerField()
+    weight = models.FloatField()
 
     def __unicode__(self):
         return self.common_name
@@ -14,6 +15,7 @@ class Animal(models.Model):
 def animal_pre_save_check(signal, sender, instance, **kwargs):
     "A signal that is used to check the type of data loaded from fixtures"
     print 'Count = %s (%s)' % (instance.count, type(instance.count))
+    print 'Weight = %s (%s)' % (instance.weight, type(instance.weight))
 
 class Plant(models.Model):
     name = models.CharField(max_length=150)
@@ -69,7 +71,7 @@ __test__ = {'API_TESTS':"""
 # Create a new animal. Without a sequence reset, this new object
 # will take a PK of 1 (on Postgres), and the save will fail.
 # This is a regression test for ticket #3790.
->>> animal = Animal(name='Platypus', latin_name='Ornithorhynchus anatinus', count=2)
+>>> animal = Animal(name='Platypus', latin_name='Ornithorhynchus anatinus', count=2, weight=2.3)
 >>> animal.save()
 
 ###############################################
@@ -149,12 +151,13 @@ No fixture data found for 'bad_fixture2'. (File format may be invalid.)
 [1, 2, 3, 4, 5, 6, 7, 8]
 
 ###############################################
-# Test for ticket #8298 - Field values should be coerced into the correct type
-# by the deserializer, not as part of the database write.
+# Test for tickets #8298, #9942 - Field values should be coerced into the
+# correct type by the deserializer, not as part of the database write.
 
 >>> models.signals.pre_save.connect(animal_pre_save_check)
 >>> management.call_command('loaddata', 'animal.xml', verbosity=0)
 Count = 42 (<type 'int'>)
+Weight = 1.2 (<type 'float'>)
 
 >>> models.signals.pre_save.disconnect(animal_pre_save_check)