Fixed #18782 -- Prevented sql_flush to flush views

Thanks rodolfo_3 for the report and the initial patch, and
Josh Smeaton, Shai Berger and Tim Graham for the reviews.

django/core/management/sql.py

@@ -129,9 +129,9 @@ def sql_flush(style, connection, only_django=False, reset_sequences=True, allow_
     models and are in INSTALLED_APPS will be included.
     """
     if only_django:
-        tables = connection.introspection.django_table_names(only_existing=True)
+        tables = connection.introspection.django_table_names(only_existing=True, include_views=False)
     else:
-        tables = connection.introspection.table_names()
+        tables = connection.introspection.table_names(include_views=False)
     seqs = connection.introspection.sequence_list() if reset_sequences else ()
     statements = connection.ops.sql_flush(style, tables, seqs, allow_cascade)
     return statements

django/db/backends/__init__.py

@@ -1274,17 +1274,20 @@ class BaseDatabaseIntrospection(object):
         """
         return self.table_name_converter(name)
 
-    def table_names(self, cursor=None):
+    def table_names(self, cursor=None, include_views=False):
         """
         Returns a list of names of all tables that exist in the database.
         The returned table list is sorted by Python's default sorting. We
         do NOT use database's ORDER BY here to avoid subtle differences
         in sorting order between databases.
         """
+        def get_names(cursor):
+            return sorted([ti.name for ti in self.get_table_list(cursor)
+                           if include_views or ti.type == 't'])
         if cursor is None:
             with self.connection.cursor() as cursor:
-                return sorted([ti.name for ti in self.get_table_list(cursor) if ti.type == 't'])
-        return sorted([ti.name for ti in self.get_table_list(cursor) if ti.type == 't'])
+                return get_names(cursor)
+        return get_names(cursor)
 
     def get_table_list(self, cursor):
         """
@@ -1293,7 +1296,7 @@ class BaseDatabaseIntrospection(object):
         """
         raise NotImplementedError('subclasses of BaseDatabaseIntrospection may require a get_table_list() method')
 
-    def django_table_names(self, only_existing=False):
+    def django_table_names(self, only_existing=False, include_views=True):
         """
         Returns a list of all table names that have associated Django models and
         are in INSTALLED_APPS.
@@ -1312,7 +1315,7 @@ class BaseDatabaseIntrospection(object):
                 tables.update(f.m2m_db_table() for f in model._meta.local_many_to_many)
         tables = list(tables)
         if only_existing:
-            existing_tables = self.table_names()
+            existing_tables = self.table_names(include_views=include_views)
             tables = [
                 t
                 for t in tables

tests/introspection/tests.py

@@ -1,6 +1,7 @@
 from __future__ import unicode_literals
 
 from django.db import connection
+from django.db.utils import DatabaseError
 from django.test import TestCase, skipUnlessDBFeature
 
 from .models import Reporter, Article
@@ -34,6 +35,23 @@ class IntrospectionTests(TestCase):
         tl = connection.introspection.django_table_names(only_existing=False)
         self.assertIs(type(tl), list)
 
+    def test_table_names_with_views(self):
+        with connection.cursor() as cursor:
+            try:
+                cursor.execute(
+                    'CREATE VIEW introspection_article_view AS SELECT headline '
+                    'from introspection_article;')
+            except DatabaseError as e:
+                if 'insufficient privileges' in str(e):
+                    self.skipTest("The test user has no CREATE VIEW privileges")
+                else:
+                    raise
+
+        self.assertIn('introspection_article_view',
+                      connection.introspection.table_names(include_views=True))
+        self.assertNotIn('introspection_article_view',
+                         connection.introspection.table_names())
+
     def test_installed_models(self):
         tables = [Article._meta.db_table, Reporter._meta.db_table]
         models = connection.introspection.installed_models(tables)