fix: incorrect link when std field has problem (backport #19744) (#19763

)

* fix: clear cache on every update in notifications

This feels like duplicate but ensures that it gets cleared in every
case. E.g. Some class might have overridden validate or ignore_validate
might be set in which case cache doesn't get cleared.

(cherry picked from commit 479e0c1)

* fix: point to custom field link instead

(cherry picked from commit be7fd7a)

Co-authored-by: Ankush Menat <ankush@frappe.io>

frappe/desk/form/meta.py

@@ -11,6 +11,7 @@
 from frappe.modules import get_module_path, load_doctype_module, scrub
 from frappe.translate import extract_messages_from_code, make_dict_from_messages
 from frappe.utils import get_html_format
+from frappe.utils.data import get_link_to_form
 
 ASSET_KEYS = (
 	"__js",
@@ -200,14 +201,19 @@ def _show_missing_doctype_msg(self, df):
 		# customizations are removed or some custom app is removed but hasn't cleaned
 		# up after itself.
 		frappe.clear_last_message()
-		customize_form_link = f'<a href="/app/customize-form/?doc_type={self.name}">Customize Form</a>'
-		frappe.throw(
-			_(
-				"Field {0} is referring to non-existing doctype {1}, please remove the field from {2} or add the required doctype."
-			).format(frappe.bold(df.fieldname), frappe.bold(df.options), customize_form_link),
-			title=_("Missing DocType"),
+
+		msg = _("Field {0} is referring to non-existing doctype {1}.").format(
+			frappe.bold(df.fieldname), frappe.bold(df.options)
 		)
 
+		if df.get("is_custom_field"):
+			custom_field_link = get_link_to_form("Custom Field", df.name)
+			msg += " " + _("Please delete the field from {2} or add the required doctype.").format(
+				custom_field_link
+			)
+
+		frappe.throw(msg, title=_("Missing DocType"))
+
 	def add_linked_document_type(self):
 		for df in self.get("fields", {"fieldtype": "Link"}):
 			if df.options:

frappe/email/doctype/notification/notification.py

@@ -45,6 +45,7 @@ def validate(self):
 		frappe.cache().hdel("notifications", self.document_type)
 
 	def on_update(self):
+		frappe.cache().hdel("notifications", self.document_type)
 		path = export_module_json(self, self.is_standard, self.module)
 		if path:
 			# js