fix(UX): Improve search relevance for link field (backport #22729) (#…

…22966)

* fix: Improve search relevance for search_link

When `locate` returns 0 it's shown on top instead it should be shown
last or not shown at all.

This is math hack to avoid using any complex SQL functionality which
isn't allowed in DB query.

(cherry picked from commit 3144422)

* fix: Give idx higher preference than meta order

Meta order in most cases is default "modified" which doesn't quite help.

idx is # of times a document is referred to somewhere else, which is
more likely to be relevant.

(cherry picked from commit fec7759)

* fix: Make search_link query postgres compatible

(cherry picked from commit 55a4449)

---------

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

frappe/desk/search.py

@@ -188,16 +188,18 @@ def search_widget(
 
 			order_by_based_on_meta = get_order_by(doctype, meta)
 			# 2 is the index of _relevance column
-			order_by = f"{order_by_based_on_meta}, `tab{doctype}`.idx desc"
+			order_by = f"`tab{doctype}`.idx desc, {order_by_based_on_meta}"
 
 			if not meta.translated_doctype:
-				formatted_fields.append(
-					"""locate({_txt}, `tab{doctype}`.`name`) as `_relevance`""".format(
-						_txt=frappe.db.escape((txt or "").replace("%", "").replace("@", "")),
-						doctype=doctype,
-					)
-				)
-				order_by = f"_relevance, {order_by}"
+				_txt = frappe.db.escape((txt or "").replace("%", "").replace("@", ""))
+				_relevance = f"(1 / nullif(locate({_txt}, `tab{doctype}`.`name`), 0))"
+				formatted_fields.append(f"""{_relevance} as `_relevance`""")
+				# Since we are sorting by alias postgres needs to know number of column we are sorting
+				if frappe.db.db_type == "mariadb":
+					order_by = f"ifnull(_relevance, -9999) desc, {order_by}"
+				elif frappe.db.db_type == "postgres":
+					# Since we are sorting by alias postgres needs to know number of column we are sorting
+					order_by = f"{len(formatted_fields)} desc nulls last, {order_by}"
 
 			ignore_permissions = (
 				True

frappe/tests/test_search.py

@@ -2,6 +2,7 @@
 # License: MIT. See LICENSE
 
 import re
+from functools import partial
 
 import frappe
 from frappe.app import make_form_dict
@@ -132,15 +133,32 @@ def test_validate_and_sanitize_search_inputs(self):
 
 	def test_reference_doctype(self):
 		"""search query methods should get reference_doctype if they want"""
-		search_link(
+		results = test_search(
 			doctype="User",
 			txt="",
 			filters=None,
 			page_length=20,
 			reference_doctype="ToDo",
 			query="frappe.tests.test_search.query_with_reference_doctype",
 		)
-		self.assertListEqual(frappe.response["results"], [])
+		self.assertListEqual(results, [])
+
+	def test_search_relevance(self):
+		search = partial(test_search, doctype="Language", filters=None, page_length=10)
+		for row in search(txt="e"):
+			self.assertTrue(row["value"].startswith("e"))
+
+		for row in search(txt="es"):
+			self.assertIn("es", row["value"])
+
+		# Assume that "es" is used at least 10 times, it should now be first
+		frappe.db.set_value("Language", "es", "idx", 10)
+		self.assertEqual("es", search(txt="es")[0]["value"])
+
+
+def test_search(*args, **kwargs):
+	search_link(*args, **kwargs)
+	return frappe.response["results"]
 
 
 @frappe.validate_and_sanitize_search_inputs