Item Wise TDS Calculation

erpnext/accounts/doctype/tax_withholding_category/tax_withholding_category.py

@@ -61,6 +61,9 @@ def get_party_details(inv):
 
 
 def get_party_tax_withholding_details(inv, tax_withholding_category=None):
+	if inv.doctype == "Payment Entry":
+		inv.tax_withholding_net_total = inv.net_total
+
 	pan_no = ""
 	parties = []
 	party_type, party = get_party_details(inv)
@@ -428,11 +431,11 @@ def get_tds_amount(ldc, parties, inv, tax_details, tax_deducted, vouchers):
 		):
 			# Get net total again as TDS is calculated on net total
 			# Grand is used to just check for threshold breach
-			net_total = 0
-			if vouchers:
-				net_total = frappe.db.get_value("Purchase Invoice", invoice_filters, "sum(net_total)")
-
-			net_total += inv.net_total
+			net_total = (
+				frappe.db.get_value("Purchase Invoice", invoice_filters, "sum(tax_withholding_net_total)")
+				or 0.0
+			)
+			net_total += inv.tax_withholding_net_total
 			supp_credit_amt = net_total - cumulative_threshold
 
 		if ldc and is_valid_certificate(

erpnext/accounts/doctype/tax_withholding_category/test_tax_withholding_category.py

@@ -186,6 +186,46 @@ class TestTaxWithholdingCategory(unittest.TestCase):
 		for d in reversed(invoices):
 			d.cancel()
 
+	def test_tds_calculation_on_net_total_partial_tds(self):
+		frappe.db.set_value(
+			"Supplier", "Test TDS Supplier4", "tax_withholding_category", "Cumulative Threshold TDS"
+		)
+		invoices = []
+
+		pi = create_purchase_invoice(supplier="Test TDS Supplier4", rate=20000, do_not_save=True)
+		pi.extend(
+			"items",
+			[
+				{
+					"doctype": "Purchase Invoice Item",
+					"item_code": frappe.db.get_value("Item", {"item_name": "TDS Item"}, "name"),
+					"qty": 1,
+					"rate": 20000,
+					"cost_center": "Main - _TC",
+					"expense_account": "Stock Received But Not Billed - _TC",
+					"apply_tds": 0,
+				},
+				{
+					"doctype": "Purchase Invoice Item",
+					"item_code": frappe.db.get_value("Item", {"item_name": "TDS Item"}, "name"),
+					"qty": 1,
+					"rate": 35000,
+					"cost_center": "Main - _TC",
+					"expense_account": "Stock Received But Not Billed - _TC",
+					"apply_tds": 1,
+				},
+			],
+		)
+		pi.save()
+		pi.submit()
+		invoices.append(pi)
+
+		self.assertEqual(pi.taxes[0].tax_amount, 5500)
+
+		# cancel invoices to avoid clashing
+		for d in reversed(invoices):
+			d.cancel()
+
 	def test_multi_category_single_supplier(self):
 		frappe.db.set_value(
 			"Supplier", "Test TDS Supplier5", "tax_withholding_category", "Test Service Category"

erpnext/controllers/taxes_and_totals.py

@@ -64,6 +64,18 @@ class calculate_taxes_and_totals(object):
 		self._cleanup()
 		self.calculate_total_net_weight()
 
+	def calculate_tax_withholding_net_total(self):
+		if hasattr(self.doc, "tax_withholding_net_total"):
+			sum_net_amount = 0
+			sum_base_net_amount = 0
+			for item in self.doc.get("items"):
+				if hasattr(item, "apply_tds") and item.apply_tds:
+					sum_net_amount += item.net_amount
+					sum_base_net_amount += item.base_net_amount
+
+			self.doc.tax_withholding_net_total = sum_net_amount
+			self.doc.base_tax_withholding_net_total = sum_base_net_amount
+
 	def validate_item_tax_template(self):
 		for item in self.doc.get("items"):
 			if item.item_code and item.get("item_tax_template"):

erpnext/patches.txt

@@ -316,3 +316,4 @@ erpnext.patches.v14_0.create_accounting_dimensions_in_subcontracting_doctypes
 erpnext.patches.v14_0.fix_subcontracting_receipt_gl_entries
 erpnext.patches.v14_0.migrate_remarks_from_gl_to_payment_ledger
 erpnext.patches.v14_0.create_accounting_dimensions_for_asset_capitalization
+erpnext.patches.v14_0.update_tds_fields

erpnext/patches/v14_0/update_tds_fields.py

@@ -0,0 +1,22 @@
+import frappe
+
+def execute():
+	frappe.db.sql("""
+			UPDATE 
+					`tabPurchase Invoice Item`
+			INNER JOIN 
+					`tabPurchase Invoice`
+			ON 
+					`tabPurchase Invoice`.name = `tabPurchase Invoice Item`.parent
+			SET 
+					`tabPurchase Invoice Item`.apply_tds = 1
+			WHERE 
+					`tabPurchase Invoice`.apply_tds = 1 
+					and `tabPurchase Invoice`.docstatus = 1
+			""")
+
+	frappe.db.sql("""
+			UPDATE `tabPurchase Invoice`
+			SET tax_withholding_net_total = net_total,
+			base_tax_withholding_net_total = base_net_total
+			WHERE apply_tds = 1 and docstatus = 1""")