Fixed #24560 -- Added a --dry-run mode to the createcachetable command.

1 files changed, 16 insertions, 4 deletions

diff --git a/django/core/management/commands/createcachetable.py b/django/core/management/commands/createcachetable.py
index 4c014c88fd..c1ec4539b6 100644
--- a/django/core/management/commands/createcachetable.py
+++ b/django/core/management/commands/createcachetable.py
@@ -22,21 +22,25 @@ class Command(BaseCommand):
             default=DEFAULT_DB_ALIAS,
             help='Nominates a database onto which the cache tables will be '
             'installed. Defaults to the "default" database.')
+        parser.add_argument('--dry-run', action='store_true', dest='dry_run',
+            help='Does not create the table, just prints the SQL that would '
+            'be run.')
 
     def handle(self, *tablenames, **options):
         db = options.get('database')
         self.verbosity = int(options.get('verbosity'))
+        dry_run = options.get('dry_run')
         if len(tablenames):
             # Legacy behavior, tablename specified as argument
             for tablename in tablenames:
-                self.create_table(db, tablename)
+                self.create_table(db, tablename, dry_run)
         else:
             for cache_alias in settings.CACHES:
                 cache = caches[cache_alias]
                 if isinstance(cache, BaseDatabaseCache):
-                    self.create_table(db, cache._table)
+                    self.create_table(db, cache._table, dry_run)
 
-    def create_table(self, database, tablename):
+    def create_table(self, database, tablename, dry_run):
         cache = BaseDatabaseCache(tablename, {})
         if not router.allow_migrate_model(database, cache.cache_model_class):
             return
@@ -74,11 +78,19 @@ class Command(BaseCommand):
             full_statement.append('    %s%s' % (line, ',' if i < len(table_output) - 1 else ''))
         full_statement.append(');')
 
+        full_statement = "\n".join(full_statement)
+
+        if dry_run:
+            self.stdout.write(full_statement)
+            for statement in index_output:
+                self.stdout.write(statement)
+            return
+
         with transaction.atomic(using=database,
                                 savepoint=connection.features.can_rollback_ddl):
             with connection.cursor() as curs:
                 try:
-                    curs.execute("\n".join(full_statement))
+                    curs.execute(full_statement)
                 except DatabaseError as e:
                     raise CommandError(
                         "Cache table '%s' could not be created.\nThe error was: %s." %