Fixed #3054 -- newforms Form now keeps track of field order

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4093 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/newforms/fields.py

@@ -28,6 +28,9 @@ except NameError:
 class Field(object):
     widget = TextInput # Default widget to use when rendering this type of Field.
 
+    # Tracks each time a Field instance is created. Used to retain order.
+    creation_counter = 0
+
     def __init__(self, required=True, widget=None):
         self.required = required
         widget = widget or self.widget
@@ -35,6 +38,10 @@ class Field(object):
             widget = widget()
         self.widget = widget
 
+        # Increase the creation counter, and save our local copy.
+        self.creation_counter = Field.creation_counter
+        Field.creation_counter += 1
+
     def clean(self, value):
         """
         Validates the given value and returns its "cleaned" value as an

django/newforms/forms.py

@@ -2,6 +2,7 @@
 Form classes
 """
 
+from django.utils.datastructures import SortedDict
 from fields import Field
 from widgets import TextInput, Textarea
 from util import ErrorDict, ErrorList, ValidationError
@@ -13,10 +14,21 @@ def pretty_name(name):
     name = name[0].upper() + name[1:]
     return name.replace('_', ' ')
 
+class SortedDictFromList(SortedDict):
+    "A dictionary that keeps its keys in the order in which they're inserted."
+    # This is different than django.utils.datastructures.SortedDict, because
+    # this takes a list/tuple as the argument to __init__().
+    def __init__(self, data=None):
+        if data is None: data = []
+        self.keyOrder = [d[0] for d in data]
+        dict.__init__(self, dict(data))
+
 class DeclarativeFieldsMetaclass(type):
     "Metaclass that converts Field attributes to a dictionary called 'fields'."
     def __new__(cls, name, bases, attrs):
-        attrs['fields'] = dict([(name, attrs.pop(name)) for name, obj in attrs.items() if isinstance(obj, Field)])
+        fields = [(name, attrs.pop(name)) for name, obj in attrs.items() if isinstance(obj, Field)]
+        fields.sort(lambda x, y: cmp(x[1].creation_counter, y[1].creation_counter))
+        attrs['fields'] = SortedDictFromList(fields)
         return type.__new__(cls, name, bases, attrs)
 
 class Form(object):