fix: Tax withholding against order via Payment Entry (#36493)

* fix: Tax withholding against order via Payment Entry (#36493)

* fix: Tax withholding against order via Payment Entry

* test: Add test case

* fix: Nonetype exceptions

(cherry picked from commit 93767eb)

# Conflicts:
#	erpnext/accounts/doctype/tax_withholding_category/test_tax_withholding_category.py

* chore: resolve conflicts

---------

Co-authored-by: Deepesh Garg <deepeshgarg6@gmail.com>

erpnext/accounts/doctype/payment_entry/payment_entry.py

@@ -616,7 +616,9 @@ def set_tax_withholding(self):
 		if not self.apply_tax_withholding_amount:
 			return
 
-		net_total = self.paid_amount
+		order_amount = self.get_order_net_total()
+
+		net_total = flt(order_amount) + flt(self.unallocated_amount)
 
 		# Adding args as purchase invoice to get TDS amount
 		args = frappe._dict(
@@ -661,6 +663,20 @@ def set_tax_withholding(self):
 		for d in to_remove:
 			self.remove(d)
 
+	def get_order_net_total(self):
+		if self.party_type == "Supplier":
+			doctype = "Purchase Order"
+		else:
+			doctype = "Sales Order"
+
+		docnames = [d.reference_name for d in self.references if d.reference_doctype == doctype]
+
+		tax_withholding_net_total = frappe.db.get_value(
+			doctype, {"name": ["in", docnames]}, ["sum(base_net_total)"]
+		)
+
+		return tax_withholding_net_total
+
 	def apply_taxes(self):
 		self.initialize_taxes()
 		self.determine_exclusive_rate()

erpnext/accounts/doctype/tax_withholding_category/test_tax_withholding_category.py

@@ -186,6 +186,42 @@ def test_tds_calculation_on_net_total(self):
 		for d in reversed(invoices):
 			d.cancel()
 
+	def test_tds_deduction_for_po_via_payment_entry(self):
+		from erpnext.accounts.doctype.payment_entry.payment_entry import get_payment_entry
+
+		frappe.db.set_value(
+			"Supplier", "Test TDS Supplier8", "tax_withholding_category", "Cumulative Threshold TDS"
+		)
+		order = create_purchase_order(supplier="Test TDS Supplier8", rate=40000, do_not_save=True)
+
+		# Add some tax on the order
+		order.append(
+			"taxes",
+			{
+				"category": "Total",
+				"charge_type": "Actual",
+				"account_head": "_Test Account VAT - _TC",
+				"cost_center": "Main - _TC",
+				"tax_amount": 8000,
+				"description": "Test",
+				"add_deduct_tax": "Add",
+			},
+		)
+
+		order.save()
+
+		order.apply_tds = 1
+		order.tax_withholding_category = "Cumulative Threshold TDS"
+		order.submit()
+
+		self.assertEqual(order.taxes[0].tax_amount, 4000)
+
+		payment = get_payment_entry(order.doctype, order.name)
+		payment.apply_tax_withholding_amount = 1
+		payment.tax_withholding_category = "Cumulative Threshold TDS"
+		payment.submit()
+		self.assertEqual(payment.taxes[0].tax_amount, 4000)
+
 	def test_multi_category_single_supplier(self):
 		frappe.db.set_value(
 			"Supplier", "Test TDS Supplier5", "tax_withholding_category", "Test Service Category"
@@ -275,6 +311,37 @@ def cancel_invoices():
 		frappe.get_doc("Sales Invoice", d).cancel()
 
 
+def create_purchase_order(**args):
+	# return purchase order doc object
+	item = frappe.db.get_value("Item", {"item_name": "TDS Item"}, "name")
+	args = frappe._dict(args)
+	po = frappe.get_doc(
+		{
+			"doctype": "Purchase Order",
+			"transaction_date": today(),
+			"schedule_date": today(),
+			"apply_tds": 0 if args.do_not_apply_tds else 1,
+			"supplier": args.supplier,
+			"company": "_Test Company",
+			"taxes_and_charges": "",
+			"currency": "INR",
+			"taxes": [],
+			"items": [
+				{
+					"doctype": "Purchase Order Item",
+					"item_code": item,
+					"qty": args.qty or 1,
+					"rate": args.rate or 10000,
+					"cost_center": "Main - _TC",
+					"expense_account": "Stock Received But Not Billed - _TC",
+				}
+			],
+		}
+	)
+	po.save()
+	return po
+
+
 def create_purchase_invoice(**args):
 	# return sales invoice doc object
 	item = frappe.db.get_value("Item", {"item_name": "TDS Item"}, "name")
@@ -351,6 +418,8 @@ def create_records():
 		"Test TDS Supplier4",
 		"Test TDS Supplier5",
 		"Test TDS Supplier6",
+		"Test TDS Supplier7",
+		"Test TDS Supplier8",
 	]:
 		if frappe.db.exists("Supplier", name):
 			continue