refactor!: Prefix all custom fieldnames created from Desk (frappe#21355)

* fix: actualy remove special characterso

`or "_"` is always truthy, this code didn't do anything

* refactor!: Prefix all custom fieldnames created from Desk

 Why?
 - Custom and standard field clashes are frequent. This will prevent it
   from happening. E.g. recent `incoterm` field addition in ERPNext.
 - Apps/fixtures can still specify exact fieldnames

* test: custom field naming

frappe/custom/doctype/custom_field/custom_field.py

@@ -40,8 +40,9 @@ def set_fieldname(self):
 
 			# remove special characters from fieldname
 			self.fieldname = "".join(
-				filter(lambda x: x.isdigit() or x.isalpha() or "_", cstr(label).replace(" ", "_"))
+				[c for c in cstr(label).replace(" ", "_") if c.isdigit() or c.isalpha() or c == "_"]
 			)
+			self.fieldname = f"custom_{self.fieldname}"
 
 		# fieldnames should be lowercase
 		self.fieldname = self.fieldname.lower()

frappe/custom/doctype/customize_form/test_customize_form.py

@@ -14,10 +14,11 @@
 
 class TestCustomizeForm(FrappeTestCase):
 	def insert_custom_field(self):
-		frappe.delete_doc_if_exists("Custom Field", "Event-test_custom_field")
-		frappe.get_doc(
+		frappe.delete_doc_if_exists("Custom Field", "Event-custom_test_field")
+		self.field = frappe.get_doc(
 			{
 				"doctype": "Custom Field",
+				"fieldname": "custom_test_field",
 				"dt": "Event",
 				"label": "Test Custom Field",
 				"description": "A Custom Field for Testing",
@@ -36,7 +37,7 @@ def setUp(self):
 		frappe.clear_cache(doctype="Event")
 
 	def tearDown(self):
-		frappe.delete_doc("Custom Field", "Event-test_custom_field")
+		frappe.delete_doc("Custom Field", self.field.name)
 		frappe.db.commit()
 		frappe.clear_cache(doctype="Event")
 
@@ -60,7 +61,7 @@ def test_fetch_to_customize(self):
 		self.assertEqual(d.doc_type, "Event")
 
 		self.assertEqual(len(d.get("fields")), len(frappe.get_doc("DocType", d.doc_type).fields) + 1)
-		self.assertEqual(d.get("fields")[-1].fieldname, "test_custom_field")
+		self.assertEqual(d.get("fields")[-1].fieldname, self.field.fieldname)
 		self.assertEqual(d.get("fields", {"fieldname": "event_type"})[0].in_list_view, 1)
 
 		return d
@@ -129,21 +130,21 @@ def test_save_customization_field_property(self):
 
 	def test_save_customization_custom_field_property(self):
 		d = self.get_customize_form("Event")
-		self.assertEqual(frappe.db.get_value("Custom Field", "Event-test_custom_field", "reqd"), 0)
+		self.assertEqual(frappe.db.get_value("Custom Field", self.field.name, "reqd"), 0)
 
-		custom_field = d.get("fields", {"fieldname": "test_custom_field"})[0]
+		custom_field = d.get("fields", {"fieldname": self.field.fieldname})[0]
 		custom_field.reqd = 1
 		custom_field.no_copy = 1
 		d.run_method("save_customization")
-		self.assertEqual(frappe.db.get_value("Custom Field", "Event-test_custom_field", "reqd"), 1)
-		self.assertEqual(frappe.db.get_value("Custom Field", "Event-test_custom_field", "no_copy"), 1)
+		self.assertEqual(frappe.db.get_value("Custom Field", self.field.name, "reqd"), 1)
+		self.assertEqual(frappe.db.get_value("Custom Field", self.field.name, "no_copy"), 1)
 
 		custom_field = d.get("fields", {"is_custom_field": True})[0]
 		custom_field.reqd = 0
 		custom_field.no_copy = 0
 		d.run_method("save_customization")
-		self.assertEqual(frappe.db.get_value("Custom Field", "Event-test_custom_field", "reqd"), 0)
-		self.assertEqual(frappe.db.get_value("Custom Field", "Event-test_custom_field", "no_copy"), 0)
+		self.assertEqual(frappe.db.get_value("Custom Field", self.field.name, "reqd"), 0)
+		self.assertEqual(frappe.db.get_value("Custom Field", self.field.name, "no_copy"), 0)
 
 	def test_save_customization_new_field(self):
 		d = self.get_customize_form("Event")
@@ -157,28 +158,24 @@ def test_save_customization_new_field(self):
 			},
 		)
 		d.run_method("save_customization")
+
+		custom_field_name = "Event-custom_test_add_custom_field_via_customize_form"
 		self.assertEqual(
-			frappe.db.get_value(
-				"Custom Field", "Event-test_add_custom_field_via_customize_form", "fieldtype"
-			),
+			frappe.db.get_value("Custom Field", custom_field_name, "fieldtype"),
 			"Data",
 		)
 
 		self.assertEqual(
-			frappe.db.get_value(
-				"Custom Field", "Event-test_add_custom_field_via_customize_form", "insert_after"
-			),
+			frappe.db.get_value("Custom Field", custom_field_name, "insert_after"),
 			last_fieldname,
 		)
 
-		frappe.delete_doc("Custom Field", "Event-test_add_custom_field_via_customize_form")
-		self.assertEqual(
-			frappe.db.get_value("Custom Field", "Event-test_add_custom_field_via_customize_form"), None
-		)
+		frappe.delete_doc("Custom Field", custom_field_name)
+		self.assertEqual(frappe.db.get_value("Custom Field", custom_field_name), None)
 
 	def test_save_customization_remove_field(self):
 		d = self.get_customize_form("Event")
-		custom_field = d.get("fields", {"fieldname": "test_custom_field"})[0]
+		custom_field = d.get("fields", {"fieldname": self.field.fieldname})[0]
 		d.get("fields").remove(custom_field)
 		d.run_method("save_customization")
 
@@ -200,7 +197,7 @@ def test_reset_to_defaults(self):
 	def test_set_allow_on_submit(self):
 		d = self.get_customize_form("Event")
 		d.get("fields", {"fieldname": "subject"})[0].allow_on_submit = 1
-		d.get("fields", {"fieldname": "test_custom_field"})[0].allow_on_submit = 1
+		d.get("fields", {"fieldname": "custom_test_field"})[0].allow_on_submit = 1
 		d.run_method("save_customization")
 
 		d = self.get_customize_form("Event")
@@ -209,7 +206,7 @@ def test_set_allow_on_submit(self):
 		self.assertEqual(d.get("fields", {"fieldname": "subject"})[0].allow_on_submit or 0, 0)
 
 		# allow for custom field
-		self.assertEqual(d.get("fields", {"fieldname": "test_custom_field"})[0].allow_on_submit, 1)
+		self.assertEqual(d.get("fields", {"fieldname": "custom_test_field"})[0].allow_on_submit, 1)
 
 	def test_title_field_pattern(self):
 		d = self.get_customize_form("Web Form")
@@ -406,7 +403,7 @@ def test_change_to_autoincrement_autoname(self):
 
 	def test_system_generated_fields(self):
 		doctype = "Event"
-		custom_field_name = "test_custom_field"
+		custom_field_name = "custom_test_field"
 
 		custom_field = frappe.get_doc("Custom Field", {"dt": doctype, "fieldname": custom_field_name})
 		custom_field.is_system_generated = 1