Fixed #22194 -- Added --list-tags option to check command.

Thanks Elvard for the patch.

2 files changed, 11 insertions, 2 deletions

diff --git a/django/core/checks/registry.py b/django/core/checks/registry.py
index e88e0b8c37..8217d534c6 100644
--- a/django/core/checks/registry.py
+++ b/django/core/checks/registry.py
@@ -64,8 +64,10 @@ class CheckRegistry(object):
         return errors
 
     def tag_exists(self, tag):
-        tags = chain(*[check.tags for check in self.registered_checks if hasattr(check, 'tags')])
-        return tag in tags
+        return tag in self.tags_available()
+
+    def tags_available(self):
+        return set(chain(*[check.tags for check in self.registered_checks if hasattr(check, 'tags')]))
 
 
 registry = CheckRegistry()
diff --git a/django/core/management/commands/check.py b/django/core/management/commands/check.py
index b6d2571ab0..3532ab4fa9 100644
--- a/django/core/management/commands/check.py
+++ b/django/core/management/commands/check.py
@@ -5,6 +5,7 @@ from optparse import make_option
 
 from django.apps import apps
 from django.core import checks
+from django.core.checks.registry import registry
 from django.core.management.base import BaseCommand, CommandError
 
 
@@ -16,9 +17,15 @@ class Command(BaseCommand):
     option_list = BaseCommand.option_list + (
         make_option('--tag', '-t', action='append', dest='tags',
             help='Run only checks labeled with given tag.'),
+        make_option('--list-tags', action='store_true', dest='list_tags',
+            help='List available tags.'),
     )
 
     def handle(self, *app_labels, **options):
+        if options.get('list_tags'):
+            self.stdout.write('\n'.join(sorted(registry.tags_available())))
+            return
+
         if app_labels:
             app_configs = [apps.get_app_config(app_label) for app_label in app_labels]
         else: