feat(Appointment): Duplicate appointment against serial no validation

erpnext/fixtures/custom_field.json

@@ -2198,5 +2198,60 @@
   "translatable": 0,
   "unique": 0,
   "width": null
+ },
+ {
+  "allow_in_quick_entry": 0,
+  "allow_on_submit": 0,
+  "bold": 0,
+  "collapsible": 0,
+  "collapsible_depends_on": null,
+  "columns": 0,
+  "creation": "2024-06-12 18:08:40.448672",
+  "default": null,
+  "depends_on": null,
+  "description": null,
+  "docstatus": 0,
+  "doctype": "Custom Field",
+  "dt": "Appointment Type",
+  "fetch_from": null,
+  "fetch_if_empty": 0,
+  "fieldname": "validate_duplicate_appointment",
+  "fieldtype": "Check",
+  "hidden": 0,
+  "hide_border": 0,
+  "hide_days": 0,
+  "hide_seconds": 0,
+  "ignore_user_permissions": 0,
+  "ignore_xss_filter": 0,
+  "in_global_search": 0,
+  "in_list_view": 0,
+  "in_preview": 0,
+  "in_standard_filter": 0,
+  "insert_after": "auto_assign_agent",
+  "is_system_generated": 1,
+  "is_virtual": 0,
+  "label": "Validate Duplicate Appointment against Serial/Vehicle",
+  "length": 0,
+  "mandatory_depends_on": null,
+  "modified": "2024-06-16 21:12:01.448504",
+  "module": null,
+  "name": "Appointment Type-validate_duplicate_appointment",
+  "no_copy": 0,
+  "non_negative": 0,
+  "options": null,
+  "permlevel": 0,
+  "precision": "",
+  "print_hide": 0,
+  "print_hide_if_no_value": 0,
+  "print_width": null,
+  "read_only": 0,
+  "read_only_depends_on": null,
+  "report_hide": 0,
+  "reqd": 0,
+  "search_index": 0,
+  "sort_options": 0,
+  "translatable": 0,
+  "unique": 0,
+  "width": null
  }
 ]

erpnext/hooks.py

@@ -108,6 +108,7 @@
 				"Appointment-applies_to_item_name",
 				"Appointment-project_template",
 				"Appointment-project_template_name",
+				"Appointment Type-validate_duplicate_appointment",
 
 				"Customer Feedback-applies_to_variant_of",
 				"Customer Feedback-applies_to_variant_of_name",

erpnext/overrides/appointment/appointment_hooks.py

@@ -24,6 +24,10 @@ def onload(self):
 				self.get('applies_to_vehicle')
 			))
 
+	def validate(self):
+		self.validate_duplicate_appointment()
+		super().validate()
+
 	@classmethod
 	def get_allowed_party_types(cls):
 		return super().get_allowed_party_types() + ["Customer"]
@@ -36,6 +40,26 @@ def set_missing_values_after_submit(self):
 		super().set_missing_values_after_submit()
 		self.set_applies_to_details()
 
+	def validate_duplicate_appointment(self):
+		if not frappe.get_cached_value("Appointment Type", self.appointment_type, "validate_duplicate_appointment"):
+			return
+
+		existing_appointment = frappe.db.get_value("Appointment", {
+			'scheduled_date': self.scheduled_date,
+			'appointment_type': self.appointment_type,
+			'applies_to_serial_no': self.applies_to_serial_no,
+			'docstatus': ['=', 1],
+			'name': ['!=', self.name]
+		})
+		if existing_appointment:
+			frappe.throw(_("{0} {1} already scheduled for {2} against {3} {4}").format(
+				self.appointment_type,
+				frappe.get_desk_link("Appointment", existing_appointment),
+				self.get_formatted("scheduled_date"),
+				_("Vehicle") if self.applies_to_vehicle else _("Serial No"),
+				self.applies_to_serial_no,
+			))
+
 	def validate_next_document_on_cancel(self):
 		super().validate_next_document_on_cancel()
 		project = self.get_linked_project()