Fixed #15888 -- Made tablename argument of createcachetable optional

Thanks Aymeric Augustin for the report and the documentation and
Tim Graham for the review.

django/contrib/gis/db/backends/spatialite/creation.py

@@ -1,8 +1,6 @@
 import os
 
 from django.conf import settings
-from django.core.cache import get_cache
-from django.core.cache.backends.db import BaseDatabaseCache
 from django.core.exceptions import ImproperlyConfigured
 from django.db.backends.sqlite3.creation import DatabaseCreation
 
@@ -55,10 +53,7 @@ class SpatiaLiteCreation(DatabaseCreation):
             interactive=False,
             database=self.connection.alias)
 
-        for cache_alias in settings.CACHES:
-            cache = get_cache(cache_alias)
-            if isinstance(cache, BaseDatabaseCache):
-                call_command('createcachetable', cache._table, database=self.connection.alias)
+        call_command('createcachetable', database=self.connection.alias)
 
         # Get a cursor (even though we don't need one yet). This has
         # the side effect of initializing the test database.

django/core/management/commands/createcachetable.py

@@ -1,32 +1,50 @@
 from optparse import make_option
 
+from django.conf import settings
+from django.core.cache import get_cache
 from django.core.cache.backends.db import BaseDatabaseCache
-from django.core.management.base import LabelCommand, CommandError
+from django.core.management.base import BaseCommand, CommandError
 from django.db import connections, router, transaction, models, DEFAULT_DB_ALIAS
 from django.db.utils import DatabaseError
 from django.utils.encoding import force_text
 
 
-class Command(LabelCommand):
-    help = "Creates the table needed to use the SQL cache backend."
-    args = "<tablename>"
-    label = 'tablename'
+class Command(BaseCommand):
+    help = "Creates the tables needed to use the SQL cache backend."
 
-    option_list = LabelCommand.option_list + (
+    option_list = BaseCommand.option_list + (
         make_option('--database', action='store', dest='database',
             default=DEFAULT_DB_ALIAS, help='Nominates a database onto '
-                'which the cache table will be installed. '
+                'which the cache tables will be installed. '
                 'Defaults to the "default" database.'),
     )
 
     requires_model_validation = False
 
-    def handle_label(self, tablename, **options):
+    def handle(self, *tablenames, **options):
         db = options.get('database')
+        self.verbosity = int(options.get('verbosity'))
+        if len(tablenames):
+            # Legacy behavior, tablename specified as argument
+            for tablename in tablenames:
+                self.create_table(db, tablename)
+        else:
+            for cache_alias in settings.CACHES:
+                cache = get_cache(cache_alias)
+                if isinstance(cache, BaseDatabaseCache):
+                    self.create_table(db, cache._table)
+
+    def create_table(self, database, tablename):
         cache = BaseDatabaseCache(tablename, {})
-        if not router.allow_migrate(db, cache.cache_model_class):
+        if not router.allow_migrate(database, cache.cache_model_class):
             return
-        connection = connections[db]
+        connection = connections[database]
+
+        if tablename in connection.introspection.table_names():
+            if self.verbosity > 0:
+                self.stdout.write("Cache table '%s' already exists." % tablename)
+            return
+
         fields = (
             # "key" is a reserved word in MySQL, so use "cache_key" instead.
             models.CharField(name='cache_key', max_length=255, unique=True, primary_key=True),
@@ -63,3 +81,5 @@ class Command(LabelCommand):
                         (tablename, force_text(e)))
             for statement in index_output:
                 curs.execute(statement)
+        if self.verbosity > 1:
+            self.stdout.write("Cache table '%s' created." % tablename)

django/db/backends/creation.py

@@ -356,13 +356,7 @@ class BaseDatabaseCreation(object):
             interactive=False,
             database=self.connection.alias)
 
-        from django.core.cache import get_cache
-        from django.core.cache.backends.db import BaseDatabaseCache
-        for cache_alias in settings.CACHES:
-            cache = get_cache(cache_alias)
-            if isinstance(cache, BaseDatabaseCache):
-                call_command('createcachetable', cache._table,
-                             database=self.connection.alias)
+        call_command('createcachetable', database=self.connection.alias)
 
         # Get a cursor (even though we don't need one yet). This has
         # the side effect of initializing the test database.