fix: add tax_id handling in Tax Withholding Entry (backport #53598) (#54081)

Co-authored-by: Lakshit Jain <ljain112@gmail.com>
fix: add tax_id handling in Tax Withholding Entry (#53598)

erpnext/accounts/doctype/tax_withholding_category/tax_withholding_category.py

@@ -128,6 +128,7 @@ class TaxWithholdingDetails:
 		self.party_type = party_type
 		self.party = party
 		self.company = company
+		self.tax_id = get_tax_id_for_party(self.party_type, self.party)
 
 	def get(self) -> list:
 		"""
@@ -161,6 +162,7 @@ class TaxWithholdingDetails:
 				disable_cumulative_threshold=doc.disable_cumulative_threshold,
 				disable_transaction_threshold=doc.disable_transaction_threshold,
 				taxable_amount=0,
+				tax_id=self.tax_id,
 			)
 
 			# ldc (only if valid based on posting date)
@@ -181,17 +183,13 @@ class TaxWithholdingDetails:
 		if self.party_type != "Supplier":
 			return ldc_details
 
-		# NOTE: This can be a configurable option
-		# To check if filter by tax_id is needed
-		tax_id = get_tax_id_for_party(self.party_type, self.party)
-
 		# ldc details
-		ldc_records = self.get_valid_ldc_records(tax_id)
+		ldc_records = self.get_valid_ldc_records(self.tax_id)
 		if not ldc_records:
 			return ldc_details
 
 		ldc_names = [ldc.name for ldc in ldc_records]
-		ldc_utilization_map = self.get_ldc_utilization_by_category(ldc_names, tax_id)
+		ldc_utilization_map = self.get_ldc_utilization_by_category(ldc_names, self.tax_id)
 
 		# map
 		for ldc in ldc_records:
@@ -254,4 +252,5 @@ class TaxWithholdingDetails:
 
 @allow_regional
 def get_tax_id_for_party(party_type, party):
-	return None
+	# cannot use tax_id from doc because payment and journal entry do not have tax_id field.\
+	return frappe.db.get_value(party_type, party, "tax_id")

erpnext/accounts/doctype/tax_withholding_category/test_tax_withholding_category.py

@@ -2,6 +2,7 @@
 # See license.txt
 
 import datetime
+from unittest.mock import patch
 
 import frappe
 from frappe.custom.doctype.custom_field.custom_field import create_custom_fields
@@ -3541,6 +3542,47 @@ class TestTaxWithholdingCategory(ERPNextTestSuite):
 		entry.withholding_amount = 5001  # Should be 5000 (10% of 50000)
 		self.assertRaisesRegex(frappe.ValidationError, "Withholding Amount.*does not match", pi.save)
 
+	def test_tax_id_is_set_in_all_generated_entries_from_party_doctype(self):
+		self.setup_party_with_category("Supplier", "Test TDS Supplier3", "New TDS Category")
+		frappe.db.set_value("Supplier", "Test TDS Supplier3", "tax_id", "ABCTY1234D")
+
+		pi = create_purchase_invoice(supplier="Test TDS Supplier3", rate=40000)
+		pi.submit()
+
+		entries = frappe.get_all(
+			"Tax Withholding Entry",
+			filters={"parenttype": "Purchase Invoice", "parent": pi.name},
+			fields=["name", "tax_id"],
+		)
+
+		self.assertTrue(entries)
+		self.assertTrue(all(entry.tax_id == "ABCTY1234D" for entry in entries))
+
+	def test_threshold_considers_two_parties_with_same_tax_id_with_overrided_hook(self):
+		self.setup_party_with_category("Supplier", "Test TDS Supplier1", "Cumulative Threshold TDS")
+		self.setup_party_with_category("Supplier", "Test TDS Supplier2", "Cumulative Threshold TDS")
+
+		with patch(
+			"erpnext.accounts.doctype.tax_withholding_category.tax_withholding_category.get_tax_id_for_party",
+			return_value="AAAPL1234C",
+		):
+			pi1 = create_purchase_invoice(supplier="Test TDS Supplier1", rate=20000)
+			pi1.submit()
+
+			pi2 = create_purchase_invoice(supplier="Test TDS Supplier2", rate=20000)
+
+			pi2.submit()
+
+		entries = frappe.get_all(
+			"Tax Withholding Entry",
+			filters={"parenttype": "Purchase Invoice", "parent": pi2.name},
+			fields=["status", "withholding_amount"],
+		)
+
+		self.assertEqual(len(entries), 1)
+		self.assertEqual(entries[0].status, "Settled")
+		self.assertEqual(entries[0].withholding_amount, 2000.0)
+
 
 def create_purchase_invoice(**args):
 	# return sales invoice doc object

erpnext/accounts/doctype/tax_withholding_entry/tax_withholding_entry.py

@@ -344,7 +344,6 @@ class TaxWithholdingEntry(Document):
 
 from erpnext.accounts.doctype.tax_withholding_category.tax_withholding_category import (
 	TaxWithholdingDetails,
-	get_tax_id_for_party,
 )
 
 
@@ -646,8 +645,11 @@ class TaxWithholdingController:
 
 		# NOTE: This can be a configurable option
 		# To check if filter by tax_id is needed
-		tax_id = get_tax_id_for_party(self.party_type, self.party)
-		query = query.where(entry.tax_id == tax_id) if tax_id else query.where(entry.party == self.party)
+		query = (
+			query.where(entry.tax_id == category.tax_id)
+			if category.tax_id
+			else query.where(entry.party == self.party)
+		)
 
 		return query
 
@@ -686,6 +688,7 @@ class TaxWithholdingController:
 				"company": self.doc.company,
 				"party_type": self.party_type,
 				"party": self.party,
+				"tax_id": category.tax_id,
 				"tax_withholding_category": category.name,
 				"tax_withholding_group": category.tax_withholding_group,
 				"tax_rate": category.tax_rate,
@@ -1052,6 +1055,7 @@ class TaxWithholdingController:
 				"party_type": self.party_type,
 				"party": self.party,
 				"company": self.doc.company,
+				"tax_id": category.tax_id,
 			}
 		)
 		return entry