Add manage.py delete_stale_comments command

HISTORY.rst

@@ -9,6 +9,7 @@ History
 
 * Forked and rebranded into ``django-commentary``.
 * Dropped support for Python<3.6 and Django<3.0.
+* Added the ``delete_stale_comments`` management command.
 
 1.9.1 (2019-02-20)
 ------------------

commentary/management/commands/delete_stale_comments.py

@@ -0,0 +1,42 @@
+from django.core.management.base import BaseCommand
+
+from django_comments.models import Comment
+
+
+class Command(BaseCommand):
+    help = ("Remove comments for which the related objects "
+            "don't exist anymore!")
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            '-y', '--yes', default='x', action='store_const', const='y',
+            dest='answer', help='Automatically confirm deletion',
+        )
+
+    def handle(self, *args, **kwargs):
+        verbose = kwargs['verbosity'] >= 1
+        answer = kwargs['answer']
+
+        # -v0 sets --yes
+        if not verbose:
+            answer = 'y'
+
+        for comment in Comment.objects.all():
+            if comment.content_object is None:
+                if verbose:
+                    self.stdout.write(
+                        "Comment `%s' to non-existing `%s' with PK `%s'" %
+                        (comment, comment.content_type.model, comment.object_pk))
+
+                while answer not in 'yn':
+                    answer = input("Do you wish to delete? [yN] ")
+                    if not answer:
+                        answer = 'x'
+                        continue
+                    answer = answer[0].lower()
+
+                if answer == 'y' :
+                    comment.delete()
+
+                    if verbose:
+                        self.stdout.write("Deleted comment `%s'" % comment)

docs/index.txt

@@ -20,6 +20,7 @@ Contents
    quickstart
    models
    signals
+   management_commands
    custom
    forms
    moderation

docs/management_commands.txt

@@ -0,0 +1,19 @@
+===================
+Management commands
+===================
+
+delete_stale_comments
+=====================
+
+Remove comments for which the related objects don't exist anymore!
+This is a handy house-keeping command because the comment model
+doesn't enforce cascade delete on the database level! Run:
+
+    .. code-block:: shell
+
+        manage.py delete_stale_comments
+
+This command supports the ``--yes`` flag to automatically confirm
+suggested deletions, suitable for running via cron.
+
+.. vim:ft=rst:

tests/testapp/tests/test_delete_stale_comments.py

@@ -0,0 +1,32 @@
+from django.core.management import call_command
+
+from django_comments.models import Comment
+
+from . import CommentTestCase
+from testapp.models import Article
+
+
+class CommentManagerTests(CommentTestCase):
+
+    def testDoesNotRemoveWhenNoStaleComments(self):
+        self.createSomeComments()
+        initial_count = Comment.objects.count()
+
+        call_command("delete_stale_comments", "--yes", verbosity=0)
+
+        self.assertEqual(initial_count, Comment.objects.count())
+
+    def testRemovesWhenParentObjectsAreMissing(self):
+        self.createSomeComments()
+        initial_count = Comment.objects.count()
+        article_comments_count = Comment.objects.for_model(Article).count()
+        self.assertGreater(article_comments_count, 0)
+
+        # removing articles will not remove associated comments
+        Article.objects.all().delete()
+        self.assertEqual(initial_count, Comment.objects.count())
+
+        call_command("delete_stale_comments", "--yes", verbosity=0)
+
+        self.assertEqual(0, Comment.objects.for_model(Article).count())
+        self.assertEqual(initial_count - article_comments_count, Comment.objects.count())