Made table_names() output sorted.

Fixed #18218 -- previously Django's introspection table_names() and
get_table_list() methods did not sort the output consistently. This
resulted in random order of inspected models.

This commit also removed all external usages of get_table_list().
table_names() should be used instead.

Thanks to claudep for patch and report.

django/core/management/commands/inspectdb.py

@@ -42,7 +42,7 @@ def handle_inspection(self, options):
         yield 'from %s import models' % self.db_module
         yield ''
         known_models = []
-        for table_name in connection.introspection.get_table_list(cursor):
+        for table_name in connection.introspection.table_names(cursor):
             yield 'class %s(models.Model):' % table2model(table_name)
             known_models.append(table2model(table_name))
             try:

django/core/management/sql.py

@@ -63,7 +63,7 @@ def sql_delete(app, style, connection):
 
     # Figure out which tables already exist
     if cursor:
-        table_names = connection.introspection.get_table_list(cursor)
+        table_names = connection.introspection.table_names(cursor)
     else:
         table_names = []
 

django/db/backends/__init__.py

@@ -898,10 +898,23 @@ def table_name_converter(self, name):
         """
         return name
 
-    def table_names(self):
-        "Returns a list of names of all tables that exist in the database."
-        cursor = self.connection.cursor()
-        return self.get_table_list(cursor)
+    def table_names(self, cursor=None):
+        """
+        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.
+        """
+        if cursor is None:
+            cursor = self.connection.cursor()
+        return sorted(self.get_table_list(cursor))
+
+    def get_table_list(self, cursor):
+        """
+        Returns an unsorted list of names of all tables that exist in the
+        database.
+        """
+        raise NotImplementedError
 
     def django_table_names(self, only_existing=False):
         """

django/db/backends/mysql/base.py

@@ -454,7 +454,7 @@ def check_constraints(self, table_names=None):
         """
         cursor = self.cursor()
         if table_names is None:
-            table_names = self.introspection.get_table_list(cursor)
+            table_names = self.introspection.table_names(cursor)
         for table_name in table_names:
             primary_key_column_name = self.introspection.get_primary_key_column(cursor, table_name)
             if not primary_key_column_name:

django/db/backends/sqlite3/base.py

@@ -295,7 +295,7 @@ def check_constraints(self, table_names=None):
         """
         cursor = self.cursor()
         if table_names is None:
-            table_names = self.introspection.get_table_list(cursor)
+            table_names = self.introspection.table_names(cursor)
         for table_name in table_names:
             primary_key_column_name = self.introspection.get_primary_key_column(cursor, table_name)
             if not primary_key_column_name:

tests/regressiontests/introspection/tests.py

@@ -40,6 +40,7 @@ class IntrospectionTests(TestCase):
 
     def test_table_names(self):
         tl = connection.introspection.table_names()
+        self.assertEqual(tl, sorted(tl))
         self.assertTrue(Reporter._meta.db_table in tl,
                      "'%s' isn't in table_list()." % Reporter._meta.db_table)
         self.assertTrue(Article._meta.db_table in tl,