import changes from Django 1.11.1

Author: michiya

README.rst

@@ -17,7 +17,7 @@ Microsoft SQL Server and Azure SQL Database.
 Features
 --------
 
--  Supports Django 1.11.0
+-  Supports Django 1.11.1
 -  Supports Microsoft SQL Server 2005, 2008/2008R2, 2012, 2014, 2016 and
    Azure SQL Database
 -  Supports LIMIT+OFFSET and offset w/o LIMIT emulation.
@@ -31,7 +31,7 @@ Features
 Dependencies
 ------------
 
--  Django 1.11.0
+-  Django 1.11.1
 -  pyodbc 3.0 or newer
 
 Installation

setup.py

@@ -19,7 +19,7 @@
 
 setup(
     name='django-pyodbc-azure',
-    version='1.11.0.0',
+    version='1.11.1.0',
     description='Django backend for Microsoft SQL Server and Azure SQL Database using pyodbc',
     long_description=open('README.rst').read(),
     author='Michiya Takahashi',
@@ -28,7 +28,7 @@
     license='BSD',
     packages=['sql_server', 'sql_server.pyodbc'],
     install_requires=[
-        'Django>=1.11,<1.12',
+        'Django>=1.11.1,<1.12',
         'pyodbc>=3.0',
     ],
     classifiers=CLASSIFIERS,

sql_server/pyodbc/base.py

@@ -7,7 +7,7 @@
 
 from django.core.exceptions import ImproperlyConfigured
 from django import VERSION
-if VERSION[:3] < (1,11,0) or VERSION[:2] >= (1,12):
+if VERSION[:3] < (1,11,1) or VERSION[:2] >= (1,12):
     raise ImproperlyConfigured("Django %d.%d.%d is not supported." % VERSION[:3])
 
 try:

sql_server/pyodbc/schema.py

@@ -4,6 +4,7 @@
 from django.db.backends.base.schema import (
     BaseDatabaseSchemaEditor, logger, _related_non_m2m_objects,
 )
+from django.db.models import Index
 from django.db.models.fields import AutoField, BigAutoField
 from django.db.models.fields.related import ManyToManyField
 from django.db.transaction import TransactionManagementError
@@ -111,8 +112,16 @@ def _alter_field(self, model, old_field, new_field, old_type, new_type,
         # True               | False            | True               | True
         if old_field.db_index and not old_field.unique and (not new_field.db_index or new_field.unique):
             # Find the index for this field
-            index_names = self._constraint_names(model, [old_field.column], index=True)
+            meta_index_names = {index.name for index in model._meta.indexes}
+            # Retrieve only BTREE indexes since this is what's created with
+            # db_index=True.
+            index_names = self._constraint_names(model, [old_field.column], index=True, type_=Index.suffix)
             for index_name in index_names:
+                if index_name in meta_index_names:
+                    # The only way to check if an index was created with
+                    # db_index=True or with Index(['field'], name='foo')
+                    # is to look at its name (refs #28053).
+                    continue
                 self.execute(self._delete_constraint_sql(self.sql_delete_index, model, index_name))
         # Change check constraints?
         if old_db_params['check'] != new_db_params['check'] and old_db_params['check']: