From feee6d8805b8f6f955406ddec834ff577826065f Mon Sep 17 00:00:00 2001
From: Russell Keith-Magee <russell@keith-magee.com>
Date: Sat, 28 Jan 2006 17:58:44 +0000
Subject: [PATCH] magic-removal: Added checks to prevent creation of models
 with related/m2m field names that collide with defined field names

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@2146 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/db/models/fields/__init__.py |  2 ++
 django/db/models/options.py         | 38 ++++++++++++++++++++++++++---
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index b0883f1e73..19279d45e7 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -27,6 +27,8 @@ get_ul_class = lambda x: 'radiolist%s' % ((x == HORIZONTAL) and ' inline' or '')
 
 class FieldDoesNotExist(Exception):
     pass
+class FieldCollision(Exception):
+    pass
 
 def manipulator_validator_unique(f, opts, self, field_data, all_data):
     "Validates that the value is unique for this field."
diff --git a/django/db/models/options.py b/django/db/models/options.py
index 026104aa0e..652d9446bb 100644
--- a/django/db/models/options.py
+++ b/django/db/models/options.py
@@ -1,6 +1,6 @@
 from django.db.models.related import RelatedObject
 from django.db.models.fields.related import ManyToMany
-from django.db.models.fields import AutoField, FieldDoesNotExist
+from django.db.models.fields import AutoField, FieldDoesNotExist, FieldCollision
 from django.db.models.loading import get_models
 from django.db.models.query import orderlist2sql
 from bisect import bisect
@@ -123,7 +123,23 @@ class Options:
             for klass in get_models():
                 for f in klass._meta.fields:
                     if f.rel and self == f.rel.to._meta:
-                        rel_objs.append(RelatedObject(f.rel.to, klass, f))
+                        rel_obj = RelatedObject(f.rel.to, klass, f)
+                        # Check to see if the new related field will clash with any
+                        # existing fields, m2m fields, m2m related objects or related objects
+                        if rel_obj.OLD_get_accessor_name() in [r.name for r in f.rel.to._meta.fields]:
+                            raise FieldCollision, 'Related field ' + klass._meta.object_name + \
+                                '.' + f.name + ' clashes with existing field on ' + self.object_name
+                        elif rel_obj.OLD_get_accessor_name() in [r.name for r in f.rel.to._meta.many_to_many]:
+                            raise FieldCollision, 'Related field ' + klass._meta.object_name + \
+                                '.' + f.name + ' clashes with existing m2m field on ' + self.object_name
+                        elif rel_obj.OLD_get_accessor_name() in [r.name for r in f.rel.to._meta.get_all_related_many_to_many_objects()]:
+                            raise FieldCollision, 'Related field ' + klass._meta.object_name + \
+                                '.' + f.name + ' clashes with existing related m2m field on ' + self.object_name
+                        elif rel_obj.OLD_get_accessor_name() in [r.OLD_get_accessor_name() for r in rel_objs]:
+                            raise FieldCollision, 'Related field ' + klass._meta.object_name + \
+                                '.' + f.name + ' clashes with existing related field on ' + self.object_name
+                        else:
+                            rel_objs.append(rel_obj)
             self._all_related_objects = rel_objs
             return rel_objs
 
@@ -157,7 +173,23 @@ class Options:
             for klass in get_models():
                 for f in klass._meta.many_to_many:
                     if f.rel and self == f.rel.to._meta:
-                        rel_objs.append(RelatedObject(f.rel.to, klass, f))
+                        rel_obj = RelatedObject(f.rel.to, klass, f)
+                        # Check to see if the new related field will clash with any
+                        # existing fields, m2m fields, m2m related objects or related objects
+                        if rel_obj.OLD_get_accessor_name() in [r.name for r in f.rel.to._meta.fields]:
+                            raise FieldCollision, 'Related field ' + klass._meta.object_name + \
+                                '.' + f.name + ' clashes with existing field on ' + self.object_name
+                        elif rel_obj.OLD_get_accessor_name() in [r.name for r in f.rel.to._meta.many_to_many]:
+                            raise FieldCollision, 'Related field ' + klass._meta.object_name + \
+                                '.' + f.name + ' clashes with existing m2m field on ' + self.object_name
+                        elif rel_obj.OLD_get_accessor_name() in [r.OLD_get_accessor_name() for r in f.rel.to._meta.get_all_related_objects()]:
+                            raise FieldCollision, 'Related field ' + klass._meta.object_name + \
+                                '.' + f.name + ' clashes with existing related field on ' + self.object_name
+                        elif rel_obj.OLD_get_accessor_name() in [r.name for r in rel_objs]:
+                            raise FieldCollision, 'Related field ' + klass._meta.object_name + \
+                                '.' + f.name + ' clashes with existing related m2m field on ' + self.object_name
+                        else:
+                            rel_objs.append(rel_obj)
             self._all_related_many_to_many_objects = rel_objs
             return rel_objs