refactor: allow root deletion by default for nested set

* deprecate allow_root_deletion param in on_trash nestedset hook
* allowed to turn root deletion off by allow_root_deletion class variable
in doctype controller

frappe/core/doctype/doctype/doctype.json

@@ -45,7 +45,6 @@
   "allow_events_in_timeline",
   "allow_auto_repeat",
   "make_attachments_public",
-  "allow_root_deletion",
   "view_settings",
   "title_field",
   "show_title_field_in_link",
@@ -606,13 +605,6 @@
    "fieldname": "make_attachments_public",
    "fieldtype": "Check",
    "label": "Make Attachments Public by Default"
-  },
-  {
-   "default": "0",
-   "depends_on": "is_tree",
-   "fieldname": "allow_root_deletion",
-   "fieldtype": "Check",
-   "label": "Allow Root Deletion"
   }
  ],
  "icon": "fa fa-bolt",

frappe/custom/doctype/customize_form/customize_form.json

@@ -13,14 +13,12 @@
   "search_fields",
   "column_break_5",
   "istable",
-  "is_tree",
   "editable_grid",
   "quick_entry",
   "track_changes",
   "track_views",
   "allow_auto_repeat",
   "allow_import",
-  "allow_root_deletion",
   "fields_section_break",
   "fields",
   "naming_section",
@@ -339,20 +337,6 @@
    "fieldname": "make_attachments_public",
    "fieldtype": "Check",
    "label": "Make Attachments Public by Default"
-  },
-  {
-   "default": "0",
-   "fieldname": "is_tree",
-   "fieldtype": "Check",
-   "label": "Is Tree",
-   "read_only": 1
-  },
-  {
-   "default": "0",
-   "depends_on": "is_tree",
-   "fieldname": "allow_root_deletion",
-   "fieldtype": "Check",
-   "label": "Allow Root Deletion"
   }
  ],
  "hide_toolbar": 1,

frappe/custom/doctype/customize_form/customize_form.py

@@ -570,8 +570,6 @@ doctype_properties = {
 	"default_print_format": "Data",
 	"allow_copy": "Check",
 	"istable": "Check",
-	'is_tree': 'Check',
-	'allow_root_deletion': 'Check',
 	"quick_entry": "Check",
 	"editable_grid": "Check",
 	"max_attachments": "Int",

frappe/utils/nestedset.py

@@ -271,13 +271,18 @@ class NestedSet(Document):
 		update_nsm(self)
 		self.validate_ledger()
 
-	def on_trash(self):
+	def on_trash(self, allow_root_deletion=False):
+		"""
+		Runs on deletion of a document/node
+
+		:param allow_root_deletion: used for allowing root document deletion (DEPRECATED)
+		"""
+
 		if not getattr(self, "nsm_parent_field", None):
 			self.nsm_parent_field = frappe.scrub(self.doctype) + "_parent"
 
 		parent = self.get(self.nsm_parent_field)
-		allow_root_deletion = self.meta.allow_root_deletion
-		if not parent and not allow_root_deletion:
+		if not parent and not getattr(self, "allow_root_deletion", True):
 			frappe.throw(_("Root {0} cannot be deleted").format(_(self.doctype)))
 
 		# cannot delete non-empty group