Fixed #27096 -- Fixed primary key introspection for sqlite3 backend

django/db/backends/sqlite3/introspection.py

@@ -214,7 +214,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         results = results[results.index('(') + 1:results.rindex(')')]
         for field_desc in results.split(','):
             field_desc = field_desc.strip()
-            m = re.search('"(.*)".*PRIMARY KEY( AUTOINCREMENT)?$', field_desc)
+            m = re.search('"(.*)".*PRIMARY KEY( AUTOINCREMENT)?', field_desc)
             if m:
                 return m.groups()[0]
         return None

tests/introspection/models.py

@@ -15,7 +15,7 @@ class City(models.Model):
 
 @python_2_unicode_compatible
 class District(models.Model):
-    city = models.ForeignKey(City, models.CASCADE)
+    city = models.ForeignKey(City, models.CASCADE, primary_key=True)
     name = models.CharField(max_length=50)
 
     def __str__(self):

tests/introspection/tests.py

@@ -6,7 +6,7 @@ from django.db import connection
 from django.db.utils import DatabaseError
 from django.test import TransactionTestCase, mock, skipUnlessDBFeature
 
-from .models import Article, ArticleReporter, City, Reporter
+from .models import Article, ArticleReporter, City, District, Reporter
 
 
 class IntrospectionTests(TransactionTestCase):
@@ -165,7 +165,9 @@ class IntrospectionTests(TransactionTestCase):
     def test_get_primary_key_column(self):
         with connection.cursor() as cursor:
             primary_key_column = connection.introspection.get_primary_key_column(cursor, Article._meta.db_table)
+            pk_fk_column = connection.introspection.get_primary_key_column(cursor, District._meta.db_table)
         self.assertEqual(primary_key_column, 'id')
+        self.assertEqual(pk_fk_column, 'city_id')
 
     def test_get_indexes(self):
         with connection.cursor() as cursor: