fix: unable to create partial invoice with auto fetch terms enabled

With 'Automatically Fetch Payment Terms' enabled in Accounts Settings,
partial invoice creation from Orders wasn't possible, as the payment schedule
wasn't recalculated.

erpnext/controllers/accounts_controller.py

@@ -1662,11 +1662,8 @@ def set_payment_schedule(self):
 				)
 				self.append("payment_schedule", data)
 
-		if not (
-			automatically_fetch_payment_terms
-			and self.linked_order_has_payment_terms(po_or_so, fieldname, doctype)
-		):
-			for d in self.get("payment_schedule"):
+		def _set_schedule(doc):
+			for d in doc.get("payment_schedule"):
 				if d.invoice_portion:
 					d.payment_amount = flt(
 						grand_total * flt(d.invoice_portion / 100), d.precision("payment_amount")
@@ -1677,9 +1674,21 @@ def set_payment_schedule(self):
 					d.outstanding = d.payment_amount
 				elif not d.invoice_portion:
 					d.base_payment_amount = flt(
-						d.payment_amount * self.get("conversion_rate"), d.precision("base_payment_amount")
+						d.payment_amount * doc.get("conversion_rate"), d.precision("base_payment_amount")
 					)
 
+		if not (
+			automatically_fetch_payment_terms
+			and self.linked_order_has_payment_terms(po_or_so, fieldname, doctype)
+		):
+			_set_schedule(self)
+		else:
+			# if partial invoice, set schedule
+			if self.doctype in ["Purchase Invoice", "Sales Invoice"]:
+				po_or_so_total_qty = frappe.db.get_value(doctype, po_or_so, "total_qty")
+				if po_or_so_total_qty != self.total_qty:
+					_set_schedule(self)
+
 	def get_order_details(self):
 		if self.doctype == "Sales Invoice":
 			po_or_so = self.get("items")[0].get("sales_order")