fix: clear payment schedule in purchase invoice for is_paid

(cherry picked from commit e1fc239)

Author: Sanket322

erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js

@@ -399,6 +399,8 @@ erpnext.accounts.PurchaseInvoice = class PurchaseInvoice extends erpnext.buying.
 		hide_fields(this.frm.doc);
 		if (cint(this.frm.doc.is_paid)) {
 			this.frm.set_value("allocate_advances_automatically", 0);
+			this.frm.set_value("payment_terms_template", "");
+			this.frm.set_value("payment_schedule", []);
 			if (!this.frm.doc.company) {
 				this.frm.set_value("is_paid", 0);
 				frappe.msgprint(__("Please specify Company to proceed"));

erpnext/controllers/accounts_controller.py

@@ -464,10 +464,14 @@ def validate_deferred_start_and_end_date(self):
 					)
 
 	def validate_invoice_documents_schedule(self):
-		if self.is_return:
+		if (
+			self.is_return
+			or (self.doctype == "Purchase Invoice" and self.is_paid)
+			or (self.doctype == "Sales Invoice" and self.is_pos)
+			or self.get("is_opening") == "Yes"
+		):
 			self.payment_terms_template = ""
 			self.payment_schedule = []
-			return
 
 		self.validate_payment_schedule_dates()
 		self.set_due_date()
@@ -2342,9 +2346,6 @@ def validate_payment_schedule_dates(self):
 		dates = []
 		li = []
 
-		if self.doctype == "Sales Invoice" and self.is_pos:
-			return
-
 		for d in self.get("payment_schedule"):
 			if self.doctype == "Sales Order" and getdate(d.due_date) < getdate(self.transaction_date):
 				frappe.throw(
@@ -2361,9 +2362,6 @@ def validate_payment_schedule_dates(self):
 			frappe.throw(_("Rows with duplicate due dates in other rows were found: {0}").format(duplicates))
 
 	def validate_payment_schedule_amount(self):
-		if (self.doctype == "Sales Invoice" and self.is_pos) or self.get("is_opening") == "Yes":
-			return
-
 		party_account_currency = self.get("party_account_currency")
 		if not party_account_currency:
 			party_type, party = self.get_party()