Fixes #2

README.md

@@ -21,7 +21,7 @@ Requirements:
 
 * Django 1.11 or later.
 * PostgreSQL or SQLite database backend. (Partial indexes are not supported on MySQL, and require major hackery on Oracle.)
-* Python 2.7, 3.4, 3.5, or 3.6. Other versions will probably work as well, but have not been tested yet.
+* Python 2.7 and 3.4 - 3.6. (All Python versions supported by Django 1.11.)
 
 ## Usage
 
@@ -70,10 +70,13 @@ But the constraints are part of the business logic, and best kept close to the m
 
 ## Version History
 
-### 0.2.0 (latest)
+## 0.2.1 (latest)
+* Ensure that automatically generated index names depend on the "unique" and "where" parameters. Otherwise two indexes with the same fields would be considered identical by Django.
+
+### 0.2.0
 * Fully tested SQLite and PostgreSQL support.
 * Tests for generated SQL statements, adding and removing indexes, and that unique constraints work when inserting rows into the db tables.
-* Python 2.7, 3.4, 3.5, 3.6 support.
+* Python 2.7, 3.4-3.6 support.
 
 ### 0.1.1
 * Experimental SQLite support.

partial_index/__init__.py

@@ -1,6 +1,6 @@
 # Provide a nicer error message than failing to import models.Index.
 
-VERSION = (0, 2, 0)
+VERSION = (0, 2, 1)
 __version__ = '.'.join(str(v) for v in VERSION)
 
 
@@ -71,3 +71,31 @@ def create_sql(self, model, schema_editor, using=''):
         sql_template = self.sql_create_index[vendor]
         sql_parameters = self.get_sql_create_template_values(model, schema_editor, using)
         return sql_template % sql_parameters
+
+    def name_hash_extra_data(self):
+        return [str(self.unique), self.where]
+
+    def set_name_with_model(self, model):
+        """Sets an unique generated name for the index.
+
+        PartialIndex would like to only override "hash_data = ...", but the entire method must be duplicated for that.
+        """
+        table_name = model._meta.db_table
+        column_names = [model._meta.get_field(field_name).column for field_name, order in self.fields_orders]
+        column_names_with_order = [
+            (('-%s' if order else '%s') % column_name)
+            for column_name, (field_name, order) in zip(column_names, self.fields_orders)
+        ]
+        # The length of the parts of the name is based on the default max
+        # length of 30 characters.
+        hash_data = [table_name] + column_names_with_order + [self.suffix] + self.name_hash_extra_data()
+        self.name = '%s_%s_%s' % (
+            table_name[:11],
+            column_names[0][:7],
+            '%s_%s' % (self._hash_generator(*hash_data), self.suffix),
+        )
+        assert len(self.name) <= self.max_name_length, (
+            'Index too long for multiple database support. Is self.suffix '
+            'longer than 3 characters?'
+        )
+        self.check_name()

setup.py

@@ -6,13 +6,13 @@
 setup(
     name='django-partial-index',
     packages=['partial_index'],
-    version='0.2.0',
+    version='0.2.1',
     description='PostgreSQL and SQLite partial indexes for Django models',
     long_description=open('README.md').read(),
     author='Mattias Linnap',
     author_email='[email protected]',
     url='https://github.com/mattiaslinnap/django-partial-index',
-    download_url='https://github.com/mattiaslinnap/django-partial-index/archive/0.2.0.tar.gz',
+    download_url='https://github.com/mattiaslinnap/django-partial-index/archive/0.2.1.tar.gz',
     license='BSD',
     install_requires=[],
     classifiers=[
@@ -27,9 +27,9 @@
         'Programming Language :: Python :: 2',
         'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.3',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
         'Topic :: Database',
         'Topic :: Internet :: WWW/HTTP',
     ]

tests/test_partial_index.py

@@ -5,6 +5,7 @@
 """
 from django.test import SimpleTestCase
 from partial_index import PartialIndex
+from testapp.models import AB
 
 
 class PartialIndexTest(SimpleTestCase):
@@ -40,3 +41,35 @@ def test_deconstruct(self):
     def test_suffix(self):
         self.assertEqual(self.idx.suffix, 'partial')
 
+    def test_generated_name_ends_with_partial(self):
+        idx = PartialIndex(fields=['a', 'b'], unique=False, where='a IS NULL')
+        idx.set_name_with_model(AB)
+        self.assertEqual(idx.name[-8:], '_partial')
+
+    def test_field_sort_changes_generated_name(self):
+        idx1 = PartialIndex(fields=['a', 'b'], unique=False, where='a IS NULL')
+        idx1.set_name_with_model(AB)
+        idx2 = PartialIndex(fields=['a', '-b'], unique=False, where='a IS NULL')
+        idx2.set_name_with_model(AB)
+        self.assertNotEqual(idx1.name, idx2.name)
+
+    def test_field_order_changes_generated_name(self):
+        idx1 = PartialIndex(fields=['a', 'b'], unique=False, where='a IS NULL')
+        idx1.set_name_with_model(AB)
+        idx2 = PartialIndex(fields=['b', 'a'], unique=False, where='a IS NULL')
+        idx2.set_name_with_model(AB)
+        self.assertNotEqual(idx1.name, idx2.name)
+
+    def test_unique_changes_generated_name(self):
+        idx1 = PartialIndex(fields=['a', 'b'], unique=False, where='a IS NULL')
+        idx1.set_name_with_model(AB)
+        idx2 = PartialIndex(fields=['a', 'b'], unique=True, where='a IS NULL')
+        idx2.set_name_with_model(AB)
+        self.assertNotEqual(idx1.name, idx2.name)
+
+    def test_where_changes_generated_name(self):
+        idx1 = PartialIndex(fields=['a', 'b'], unique=False, where='a IS NULL')
+        idx1.set_name_with_model(AB)
+        idx2 = PartialIndex(fields=['a', 'b'], unique=False, where='a IS NOT NULL')
+        idx2.set_name_with_model(AB)
+        self.assertNotEqual(idx1.name, idx2.name)

tests/testapp/models.py

@@ -3,6 +3,11 @@
 from partial_index import PartialIndex
 
 
+class AB(models.Model):
+    a = models.CharField(max_length=50)
+    b = models.CharField(max_length=50)
+
+
 class User(models.Model):
     name = models.CharField(max_length=50)