fix draft deletion bug on Django CMS 4.0.x (#233)

* fix djangocms-versioning draft deletion bug (#214) (#215)

* fix djangocms-versioning draft deletion bug (#214)

Previously, `djangocms_alias.models.AliasContent.delete` deleted all plugins
related to `AliasContent.alias`, with the same language. Drafts and previously
published versions included.
This meant that the deletion of a draft resulted in plugins disappearing from
published pages.

This patch removes the mechanism entirely and instead adds a warning, notifying
the user that the last version or translation of a language got deleted.

Signed-off-by: Florian Scherf <[email protected]>

* ci: auto fixes from pre-commit hooks

for more information, see https://pre-commit.ci

---------

Signed-off-by: Florian Scherf <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

* tests: requirements: django42: fix broken djangocms-versioning URL

Signed-off-by: Florian Scherf <[email protected]>

---------

Signed-off-by: Florian Scherf <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

djangocms_alias/admin.py

@@ -1,6 +1,6 @@
 from cms.utils.permissions import get_model_permission_codename
 from cms.utils.urlutils import admin_reverse
-from django.contrib import admin
+from django.contrib import admin, messages
 from django.db.models.functions import Lower
 from django.template.loader import render_to_string
 from django.utils.translation import gettext_lazy as _
@@ -168,6 +168,17 @@ def delete_model(self, request, obj):
         if not is_versioning_enabled():
             emit_content_delete([obj], sender=self.model)
 
+        if obj.alias._default_manager.filter(language=obj.language).count() == 1:
+            message = _(
+                "Alias content for language {} deleted. A new empty alias content will be created if needed."
+            ).format(obj.language)
+            self.message_user(request, message, level=messages.WARNING)
+
+        return super().delete_model(
+            request=request,
+            obj=obj,
+        )
+
     def get_list_actions(self):
         """
         Collect rendered actions from implemented methods and return as list

djangocms_alias/models.py

@@ -305,11 +305,6 @@ def get_absolute_url(self):
     def get_template(self):
         return "djangocms_alias/alias_content.html"
 
-    @transaction.atomic
-    def delete(self, *args, **kwargs):
-        super().delete(*args, **kwargs)
-        self.alias.cms_plugins.filter(language=self.language).delete()
-
     @transaction.atomic
     def populate(self, replaced_placeholder=None, replaced_plugin=None, plugins=None):
         if not replaced_placeholder and not replaced_plugin:

tests/requirements/django_42.txt

@@ -7,4 +7,4 @@ django-sekizai
 django-parler
 
 https://github.com/django-cms/django-cms/tarball/release/4.0.1.x#egg=django-cms
-https://github.com/joshyu/djangocms-versioning/tarball/feat/django-42-compatible#egg=djangocms-versioning
+https://github.com/django-cms/djangocms-versioning/tarball/support/django-cms-4.0.x#egg=djangocms-versioning