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.

6 files changed, 22 insertions, 8 deletions

diff --git a/django/core/management/commands/inspectdb.py b/django/core/management/commands/inspectdb.py
index af2da45154..10fd9bd463 100644
--- a/django/core/management/commands/inspectdb.py
+++ b/django/core/management/commands/inspectdb.py
@@ -42,7 +42,7 @@ class Command(NoArgsCommand):
         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:
diff --git a/django/core/management/sql.py b/django/core/management/sql.py
index 454a3427aa..68c72b3487 100644
--- a/django/core/management/sql.py
+++ b/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 = []
 
diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index 0d664d452a..a85e7b984c 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -898,10 +898,23 @@ class BaseDatabaseIntrospection(object):
         """
         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):
         """
diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index 6397a0972c..1be7998c49 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -454,7 +454,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         """
         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:
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index 0b19442e78..8f883e2dc3 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -295,7 +295,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         """
         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:
diff --git a/tests/regressiontests/introspection/tests.py b/tests/regressiontests/introspection/tests.py
index 3bd9d60fa2..b425b6401d 100644
--- a/tests/regressiontests/introspection/tests.py
+++ b/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,