perf(dx): let developers know that they need to enable index on links (…

…frappe#21745)

* perf: enable indexing for dashboard links

* style: format with black

* fix: nudge index, don't enable

Many edge cases which can't be checked on-the-fly. Best to just notify
developer that they should enable indexing.

---------

Co-authored-by: Ankush Menat <[email protected]>

frappe/core/doctype/doctype/doctype.py

@@ -33,7 +33,7 @@
 from frappe.modules import get_doc_path, make_boilerplate
 from frappe.modules.import_file import get_file_path
 from frappe.query_builder.functions import Concat
-from frappe.utils import cint, flt, random_string
+from frappe.utils import cint, flt, get_table_name, random_string
 from frappe.website.utils import clear_cache
 
 if TYPE_CHECKING:
@@ -198,6 +198,7 @@ def validate(self):
 		self.set("can_change_name_type", validate_autoincrement_autoname(self))
 		self.validate_document_type()
 		validate_fields(self)
+		self.check_indexing_for_dashboard_links()
 
 		if not self.istable:
 			validate_permissions(self)
@@ -298,6 +299,23 @@ def set_default_translatable(self):
 			if d.translatable and not supports_translation(d.fieldtype):
 				d.translatable = 0
 
+	def check_indexing_for_dashboard_links(self):
+		"""Enable indexing for outgoing links used in dashboard"""
+		for d in self.fields:
+			if d.fieldtype == "Link" and not (d.unique or d.search_index):
+				referred_as_link = frappe.db.exists(
+					"DocType Link",
+					{"parent": d.options, "link_doctype": self.name, "link_fieldname": d.fieldname},
+				)
+				if not referred_as_link:
+					continue
+
+				frappe.msgprint(
+					_("{0} should be indexed because it's referred in dashboard connections").format(_(d.label)),
+					alert=True,
+					indicator="orange",
+				)
+
 	def check_developer_mode(self):
 		"""Throw exception if not developer mode or via patch"""
 		if frappe.flags.in_patch or frappe.flags.in_test: