Merge pull request #51787 from ljain112/fix-taxes-disc

fix: recalculate taxes when item tax template changes after discount
(cherry picked from commit f00aeec9b4)

erpnext/controllers/taxes_and_totals.py

@@ -39,17 +39,23 @@ class calculate_taxes_and_totals:
 		items = list(filter(lambda item: not item.get("is_alternative"), self.doc.get("items")))
 		return items
 
-	def calculate(self):
+	def calculate(self, ignore_tax_template_validation=False):
 		if not len(self.doc.items):
 			return
 
 		self.discount_amount_applied = False
+		self.need_recomputation = False
+		self.ignore_tax_template_validation = ignore_tax_template_validation
+
 		self._calculate()
 
 		if self.doc.meta.get_field("discount_amount"):
 			self.set_discount_amount()
 			self.apply_discount_amount()
 
+		if not ignore_tax_template_validation and self.need_recomputation:
+			return self.calculate(ignore_tax_template_validation=True)
+
 		# Update grand total as per cash and non trade discount
 		if self.doc.apply_discount_on == "Grand Total" and self.doc.get("is_cash_or_non_trade_discount"):
 			self.doc.grand_total -= self.doc.discount_amount
@@ -79,6 +85,9 @@ class calculate_taxes_and_totals:
 		self.calculate_total_net_weight()
 
 	def validate_item_tax_template(self):
+		if self.ignore_tax_template_validation:
+			return
+
 		if self.doc.get("is_return") and self.doc.get("return_against"):
 			return
 
@@ -122,6 +131,10 @@ class calculate_taxes_and_totals:
 							)
 						)
 
+						# For correct tax_amount calculation re-computation is required
+						if self.discount_amount_applied and self.doc.apply_discount_on == "Grand Total":
+							self.need_recomputation = True
+
 	def update_item_tax_map(self):
 		for item in self.doc.items:
 			item.item_tax_rate = get_item_tax_map(