Options.get_field() fails to check one_to_one_field, causes bogus validation error

[python@…]

I have a simple model which described 4 different bugs, one of which has a ticket with patch.
I have a patch for the last bug (labeled 'Bug3') which this ticket is for. I will file the others once I get a chance.
The problem is that Options objects which are constructed from Model classes which inherit from other Model classes may have a 'one_to_one_field' which is not in its 'fields' attribute. This can cause a bogus app validation error

meta_bug.py

from django.core import meta

# Create your models here.
class A(meta.Model):
    name = meta.SlugField(blank=False, unique=True)
    class META:
        admin = meta.Admin()
    def __repr__(self):
        return self.name

class B(meta.Model):
    a = meta.OneToOneField(A)
    ## Bug1: NEED to add another Field or Admin B edits will crash!
    class META:
        order_with_respect_to = 'a' # Ticket #930 (defect) workaround
        admin = meta.Admin()
    def __repr__(self):
        return "B - " + repr(self.get_a())

class C(meta.Model):
    b = meta.ForeignKey(B,edit_inline=meta.TABULAR,
                        to_field='a_id') # Bug2: to_field defaults to 'a' which
                                         # is wrong and causes Admin B Add's
                                         # to fail.
    data = meta.SlugField(core=True)
    def __repr__(self):
        return self.data

class _B(meta.Model):
    ap = meta.OneToOneField(A)
    class META:
        order_with_respect_to = 'a' # Ticket #930 (defect) workaround

class BP(_B):
    something = meta.SlugField() ## prevent Bug1 to show Bug3...

class CP(meta.Model):
    bp = meta.ForeignKey(BP,edit_inline=meta.TABULAR,
                         to_field='ap_id') # Bug3: Bug2 workaround no longer
                                           # works due to early model validation
                                           # error... Patch included.
    data = meta.SlugField(core=True)
    def __repr__(self):
        return self.data

This gives the following validation error:

Mya@miyu /c/django/projects/pycon
$ python manage.py install meta_bug
Traceback (most recent call last):
  File "manage.py", line 11, in ?
    execute_manager(settings)
  File "c:/python24/lib/site-packages/django-0.91-py2.4.egg/django/core/management.py", line 990, in execute_manager
    execute_from_command_line(action_mapping)
  File "c:/python24/lib/site-packages/django-0.91-py2.4.egg/django/core/management.py", line 965, in execute_from_command_line
    output = action_mapping[action](mod)
  File "c:/python24/lib/site-packages/django-0.91-py2.4.egg/django/core/management.py", line 405, in install
    sql_list = get_sql_all(mod)
  File "c:/python24/lib/site-packages/django-0.91-py2.4.egg/django/core/management.py", line 268, in get_sql_all
    return get_sql_create(mod) + get_sql_initial_data(mod)
  File "c:/python24/lib/site-packages/django-0.91-py2.4.egg/django/core/management.py", line 70, in get_sql_create
    rel_field = f.rel.get_related_field()
  File "c:/python24/lib/site-packages/django-0.91-py2.4.egg/django/core/meta/fields.py", line 846, in get_related_field
    return self.to.get_field(self.field_name)
  File "c:/python24/lib/site-packages/django-0.91-py2.4.egg/django/core/meta/__init__.py", line 463, in get_field
    raise FieldDoesNotExist, "name=%s" % name
django.core.meta.FieldDoesNotExist: name=a_id

Here is a patch which fixes this bug:

django

@@ -460 +460 @@
         for f in to_search:
             if f.name == name:
                 return f
+        if (hasattr(self, 'one_to_one_field') and
+            self.one_to_one_field is not None and
+            self.one_to_one_field.name == name):
+            return self.one_to_one_field
         raise FieldDoesNotExist, "name=%s" % name
 
     def get_order_sql(self, table_prefix=''):

[python@…]

patch (same as diff in description)

[python@…]

The problem is more protracted than I discribed, and the patch alone is not enough to fix the problem.
This will fix some validation issues, but not a real install (i.e. the error above still exists).
The end problem is that in the admin interface, if the to_field does not have the '_id' form then add and edit operations fail.
In the end its not the to_field which is 100% the problem. another patch to a lower in init.py is needed to deal with the
name resolution for OneToOne fields. This is Bug2 listed above.

The two can not be fixed in isolation and are related.

Here is the new diff:

c:/python24/lib/site-packages/django-0.91-py2.4.egg/django/core/meta/__init__.py

@@ -460 +460 @@
         for f in to_search:
             if f.name == name:
                 return f
+        if (hasattr(self, 'one_to_one_field') and
+            self.one_to_one_field is not None and
+            self.one_to_one_field.name == name):
+            return self.one_to_one_field
         raise FieldDoesNotExist, "name=%s" % name
 
     def get_order_sql(self, table_prefix=''):
@@ -1843 +1847 @@
                     # case, because they'll be dealt with later.
 
                     if f == related.field:
-                        param = getattr(new_object, related.field.rel.field_name)
+                        to = related.field.rel.to
+                        if (hasattr(to, 'one_to_one_field') and
+                            to.one_to_one_field and
+                            to.one_to_one_field.name == related.field.rel.field_name):
+                            param = getattr(new_object, related.field.rel.field_name + '_id')
+                        else:
+                            param = getattr(new_object, related.field.rel.field_name)
                     elif add and isinstance(f, AutoField):
                         param = None
                     elif change and (isinstance(f, FileField) or not child_follow.get(f.name, None)):

[python@…]

updated patch fixing more...

[Chris Beaven]

This is pretty old, pre-magic removal, and no one has commented it's still a problem.

If anyone is having this issue still, feel free to reopen.