Replaced '__' with LOOKUP_SEP constant.

django/contrib/admin/checks.py

@@ -11,6 +11,7 @@ from django.contrib.admin.utils import (
 from django.core import checks
 from django.core.exceptions import FieldDoesNotExist
 from django.db import models
+from django.db.models.constants import LOOKUP_SEP
 from django.forms.models import (
     BaseModelForm, BaseModelFormSet, _get_foreign_key,
 )
@@ -458,7 +459,7 @@ class BaseModelAdminChecks(object):
             ]
         elif field_name == '?':
             return []
-        elif '__' in field_name:
+        elif LOOKUP_SEP in field_name:
             # Skip ordering in the format field1__field2 (FIXME: checking
             # this format would be nice, but it's a little fiddly).
             return []

django/contrib/admin/utils.py

@@ -30,7 +30,7 @@ def lookup_needs_distinct(opts, lookup_path):
     """
     Returns True if 'distinct()' should be used to query the given lookup path.
     """
-    lookup_fields = lookup_path.split('__')
+    lookup_fields = lookup_path.split(LOOKUP_SEP)
     # Remove the last item of the lookup path if it is a query term
     if lookup_fields[-1] in QUERY_TERMS:
         lookup_fields = lookup_fields[:-1]

django/core/management/commands/inspectdb.py

@@ -6,6 +6,7 @@ from collections import OrderedDict
 
 from django.core.management.base import BaseCommand, CommandError
 from django.db import DEFAULT_DB_ALIAS, connections
+from django.db.models.constants import LOOKUP_SEP
 from django.utils.encoding import force_text
 
 
@@ -189,10 +190,10 @@ class Command(BaseCommand):
         if num_repl > 0:
             field_notes.append('Field renamed to remove unsuitable characters.')
 
-        if new_name.find('__') >= 0:
+        if new_name.find(LOOKUP_SEP) >= 0:
-            while new_name.find('__') >= 0:
+            while new_name.find(LOOKUP_SEP) >= 0:
-                new_name = new_name.replace('__', '_')
+                new_name = new_name.replace(LOOKUP_SEP, '_')
-            if col_name.lower().find('__') >= 0:
+            if col_name.lower().find(LOOKUP_SEP) >= 0:
                 # Only add the comment if the double underscore was in the original name
                 field_notes.append("Field renamed because it contained more than one '_' in a row.")
 

django/db/models/base.py

@@ -1617,7 +1617,7 @@ class Model(six.with_metaclass(ModelBase)):
 
         # Skip ordering in the format field1__field2 (FIXME: checking
         # this format would be nice, but it's a little fiddly).
-        fields = (f for f in fields if '__' not in f)
+        fields = (f for f in fields if LOOKUP_SEP not in f)
 
         # Skip ordering on pk. This is always a valid order_by field
         # but is an alias and therefore won't be found by opts.get_field.