clone cms with menus, make menus standalone app

cms/models/aliaspluginmodel.py

@@ -0,0 +1,64 @@
+from django.db import models
+from django.db.models import Q
+from django.utils.encoding import force_str
+
+from cms.models import CMSPlugin, Placeholder
+
+
+class AliasPluginModel(CMSPlugin):
+    """
+    AliasPlugin is deprecated,
+    and it will be removed;
+    please use the package djangocms-alias instead
+    """
+    cmsplugin_ptr = models.OneToOneField(
+        CMSPlugin,
+        on_delete=models.CASCADE,
+        related_name='cms_aliasplugin',
+        parent_link=True,
+    )
+    plugin = models.ForeignKey(
+        CMSPlugin,
+        on_delete=models.CASCADE,
+        editable=False,
+        related_name='alias_reference',
+        null=True,
+    )
+    alias_placeholder = models.ForeignKey(
+        Placeholder,
+        on_delete=models.CASCADE,
+        editable=False,
+        related_name='alias_placeholder',
+        null=True,
+    )
+
+    class Meta:
+        app_label = 'cms'
+
+    def __str__(self):
+        if self.plugin_id:
+            return f"({force_str(self.plugin.get_plugin_name())}) {self.plugin.get_plugin_instance()[0]}"
+        else:
+            return force_str(self.alias_placeholder.get_label())
+
+    def get_aliased_placeholder_id(self):
+        if self.plugin_id:
+            placeholder_id = self.plugin.placeholder_id
+        else:
+            placeholder_id = self.alias_placeholder_id
+        return placeholder_id
+
+    def is_recursive(self):
+        placeholder_id = self.get_aliased_placeholder_id()
+
+        if not placeholder_id:
+            return False
+
+        plugins = AliasPluginModel.objects.filter(
+            plugin_type='AliasPlugin',
+            placeholder_id=placeholder_id,
+        )
+        plugins = plugins.filter(
+            Q(plugin=self) | Q(plugin__placeholder=self.placeholder_id) | Q(alias_placeholder=self.placeholder_id)
+        )
+        return plugins.exists()