refactor: Consider singles for dynamic set_value usage (#21367)

Found all usage using this semgrep rule:

```yaml
    - pattern: frappe.db.set_value($DOCTYPE, ...)
    - pattern-not: frappe.db.set_value("$STR", ...)
```

frappe/core/doctype/doctype/doctype.json

@@ -755,4 +755,4 @@
  "states": [],
  "track_changes": 1,
  "translated_doctype": 1
-}
+}

frappe/core/doctype/file/file.py

@@ -236,12 +236,19 @@ class File(Document):
 		):
 			return
 
-		frappe.db.set_value(
-			self.attached_to_doctype,
-			self.attached_to_name,
-			self.attached_to_field,
-			self.file_url,
-		)
+		if frappe.get_meta(self.attached_to_doctype).issingle:
+			frappe.db.set_single_value(
+				self.attached_to_doctype,
+				self.attached_to_field,
+				self.file_url,
+			)
+		else:
+			frappe.db.set_value(
+				self.attached_to_doctype,
+				self.attached_to_name,
+				self.attached_to_field,
+				self.file_url,
+			)
 
 	def fetch_attached_to_field(self, old_file_url):
 		if self.attached_to_field:

frappe/desk/doctype/todo/todo.py

@@ -81,13 +81,21 @@ class ToDo(Document):
 			)
 			assignments.reverse()
 
-			frappe.db.set_value(
-				self.reference_type,
-				self.reference_name,
-				"_assign",
-				json.dumps(assignments),
-				update_modified=False,
-			)
+			if frappe.get_meta(self.reference_type).issingle:
+				frappe.db.set_single_value(
+					self.reference_type,
+					"_assign",
+					json.dumps(assignments),
+					update_modified=False,
+				)
+			else:
+				frappe.db.set_value(
+					self.reference_type,
+					self.reference_name,
+					"_assign",
+					json.dumps(assignments),
+					update_modified=False,
+				)
 
 		except Exception as e:
 			if frappe.db.is_table_missing(e) and frappe.flags.in_install:

frappe/desk/like.py

@@ -52,7 +52,10 @@ def _toggle_like(doctype, name, add, user=None):
 				liked_by.remove(user)
 				remove_like(doctype, name)
 
-		frappe.db.set_value(doctype, name, "_liked_by", json.dumps(liked_by), update_modified=False)
+		if frappe.get_meta(doctype).issingle:
+			frappe.db.set_single_value(doctype, "_liked_by", json.dumps(liked_by), update_modified=False)
+		else:
+			frappe.db.set_value(doctype, name, "_liked_by", json.dumps(liked_by), update_modified=False)
 
 	except frappe.db.ProgrammingError as e:
 		if frappe.db.is_column_missing(e):

frappe/model/base_document.py

@@ -646,7 +646,10 @@ class BaseDocument:
 	def update_modified(self):
 		"""Update modified timestamp"""
 		self.set("modified", now())
-		frappe.db.set_value(self.doctype, self.name, "modified", self.modified, update_modified=False)
+		if getattr(self.meta, "issingle", False):
+			frappe.db.set_single_value(self.doctype, "modified", self.modified, update_modified=False)
+		else:
+			frappe.db.set_value(self.doctype, self.name, "modified", self.modified, update_modified=False)
 
 	def _fix_numeric_types(self):
 		for df in self.meta.get("fields"):

frappe/model/document.py

@@ -1123,7 +1123,7 @@ class Document(BaseDocument):
 
 	def reset_seen(self):
 		"""Clear _seen property and set current user as seen"""
-		if getattr(self.meta, "track_seen", False):
+		if getattr(self.meta, "track_seen", False) and not getattr(self.meta, "issingle", False):
 			frappe.db.set_value(
 				self.doctype, self.name, "_seen", json.dumps([frappe.session.user]), update_modified=False
 			)
@@ -1182,15 +1182,25 @@ class Document(BaseDocument):
 		if self.name is None:
 			return
 
-		frappe.db.set_value(
-			self.doctype,
-			self.name,
-			fieldname,
-			value,
-			self.modified,
-			self.modified_by,
-			update_modified=update_modified,
-		)
+		if self.meta.issingle:
+			frappe.db.set_single_value(
+				self.doctype,
+				fieldname,
+				value,
+				modified=self.modified,
+				modified_by=self.modified_by,
+				update_modified=update_modified,
+			)
+		else:
+			frappe.db.set_value(
+				self.doctype,
+				self.name,
+				fieldname,
+				value,
+				self.modified,
+				self.modified_by,
+				update_modified=update_modified,
+			)
 
 		self.run_method("on_change")
 
@@ -1375,7 +1385,7 @@ class Document(BaseDocument):
 		if not user:
 			user = frappe.session.user
 
-		if self.meta.track_seen and not frappe.flags.read_only:
+		if self.meta.track_seen and not frappe.flags.read_only and not self.meta.issingle:
 			_seen = self.get("_seen") or []
 			_seen = frappe.parse_json(_seen)
 

frappe/tests/test_assign.py

@@ -23,16 +23,23 @@ class TestAssign(FrappeTestCase):
 		if not frappe.db.exists("User", "test@example.com"):
 			frappe.get_doc({"doctype": "User", "email": "test@example.com", "first_name": "Test"}).insert()
 
-		added = assign(todo, "test@example.com")
+		self._test_basic_assign_on_document(todo)
+
+	def _test_basic_assign_on_document(self, doc):
+		added = assign(doc, "test@example.com")
 
 		self.assertTrue("test@example.com" in [d.owner for d in added])
 
-		frappe.desk.form.assign_to.remove(todo.doctype, todo.name, "test@example.com")
+		frappe.desk.form.assign_to.remove(doc.doctype, doc.name, "test@example.com")
 
 		# assignment is cleared
-		assignments = frappe.desk.form.assign_to.get(dict(doctype=todo.doctype, name=todo.name))
+		assignments = frappe.desk.form.assign_to.get(dict(doctype=doc.doctype, name=doc.name))
 		self.assertEqual(len(assignments), 0)
 
+	def test_assign_single(self):
+		c = frappe.get_doc("Contact Us Settings")
+		self._test_basic_assign_on_document(c)
+
 	def test_assignment_count(self):
 		frappe.db.delete("ToDo")
 

frappe/tests/test_document.py

@@ -452,6 +452,13 @@ class TestDocument(FrappeTestCase):
 			frappe.exceptions.InvalidDates, doc.validate_from_to_dates, "start_date", "end_date"
 		)
 
+	def test_db_set_singles(self):
+		c = frappe.get_doc("Contact Us Settings")
+		key, val = "email_id", "admin1@example.com"
+		c.db_set(key, val)
+		changed_val = frappe.db.get_single_value(c.doctype, key)
+		self.assertEqual(val, changed_val)
+
 
 class TestDocumentWebView(FrappeTestCase):
 	def get(self, path, user="Guest"):