fix: filter Implementation is set operator (#25182) (#25195)

* Implementation is set operator. fix issue #25180

* Refactored filtrer operator `is`,
Add tests

* fix: Correct implementation for `is set`

---------

Co-authored-by: Ankush Menat <ankush@frappe.io>
(cherry picked from commit eff50e1)

# Conflicts:
#	frappe/tests/test_utils.py

Co-authored-by: Maxim Sysoev <maks4a@gmail.com>

frappe/tests/test_utils.py

@@ -175,8 +175,15 @@ def test_date_time(self):
 			)
 		)
 
-	def test_like_not_like(self):
-		doc = {"doctype": "User", "username": "test_abc", "prefix": "startswith", "suffix": "endswith"}
+	def test_filter_evaluation(self):
+		doc = {
+			"doctype": "User",
+			"username": "test_abc",
+			"prefix": "startswith",
+			"suffix": "endswith",
+			"empty": None,
+			"number": 0,
+		}
 
 		test_cases = [
 			([["username", "like", "test"]], True),
@@ -187,10 +194,15 @@ def test_like_not_like(self):
 			([["prefix", "not like", "end%"]], True),
 			([["suffix", "like", "%with"]], True),
 			([["suffix", "not like", "%end"]], True),
+			([["suffix", "is", "set"]], True),
+			([["suffix", "is", "not set"]], False),
+			([["empty", "is", "set"]], False),
+			([["empty", "is", "not set"]], True),
+			([["number", "is", "set"]], True),
 		]
 
 		for filter, expected_result in test_cases:
-			self.assertEqual(evaluate_filters(doc, filter), expected_result)
+			self.assertEqual(evaluate_filters(doc, filter), expected_result, msg=f"{filter}")
 
 
 class TestMoney(FrappeTestCase):

frappe/utils/data.py

@@ -1693,6 +1693,25 @@ def sql_like(value: str, pattern: str) -> bool:
 		return pattern in value
 
 
+def filter_operator_is(value: str, pattern: str) -> bool:
+	"""Operator `is` can have two values: 'set' or 'not set'."""
+	pattern = pattern.lower()
+
+	def is_set():
+		if value is None:
+			return False
+		elif isinstance(value, str) and not value:
+			return False
+		return True
+
+	if pattern == "set":
+		return is_set()
+	elif pattern == "not set":
+		return not is_set()
+	else:
+		frappe.throw(frappe._(f"Invalid argument for operator 'IS': {pattern}"))
+
+
 operator_map = {
 	# startswith
 	"^": lambda a, b: (a or "").startswith(b),
@@ -1710,6 +1729,7 @@ def sql_like(value: str, pattern: str) -> bool:
 	"None": lambda a, b: a is None,
 	"like": sql_like,
 	"not like": lambda a, b: not sql_like(a, b),
+	"is": filter_operator_is,
 }