Patch invalid invoice admin registration

mandelstudio/admin_fixes.py

@@ -0,0 +1,26 @@
+from django.contrib import admin
+from django.contrib.admin.sites import NotRegistered
+
+
+def patch_invoice_admin():
+    """
+    Load the invoice admin stack in a safe order and remove the invalid
+    date_hierarchy setting injected by the communications plugin.
+    """
+    try:
+        import oscar_invoices.admin  # noqa: F401
+        from oscar.core.loading import get_model
+        from ocyan.plugin.oscar_communications.oscar_invoices_extension.admin import (
+            InvoiceAdmin,
+        )
+    except ImportError:
+        return
+
+    Invoice = get_model("oscar_invoices", "Invoice")
+    InvoiceAdmin.date_hierarchy = None
+
+    try:
+        admin.site.unregister(Invoice)
+    except NotRegistered:
+        pass
+    admin.site.register(Invoice, InvoiceAdmin)

mandelstudio/apps.py

@@ -5,3 +5,8 @@ class MandelstudioConfig(AppConfig):
     default_auto_field = "django.db.models.BigAutoField"
     name = "mandelstudio"
     verbose_name = "Mandelstudio"
+
+    def ready(self):
+        from .admin_fixes import patch_invoice_admin
+
+        patch_invoice_admin()