fix(asset): incorrect date difference calculation (#26805)

erpnext/assets/doctype/asset/test_asset.py

@@ -639,7 +639,7 @@ class TestAsset(unittest.TestCase):
 		asset_name = frappe.db.get_value("Asset", {"purchase_receipt": pr.name}, 'name')
 		asset = frappe.get_doc('Asset', asset_name)
 		asset.calculate_depreciation = 1
-		asset.available_for_use_date = '2030-06-12'
+		asset.available_for_use_date = '2030-07-12'
 		asset.purchase_date = '2030-01-01'
 		asset.append("finance_books", {
 			"expected_value_after_useful_life": 1000,
@@ -653,10 +653,10 @@ class TestAsset(unittest.TestCase):
 		self.assertEqual(asset.finance_books[0].rate_of_depreciation, 50.0)
 
 		expected_schedules = [
-			["2030-12-31", 1106.85, 1106.85],
-			["2031-12-31", 3446.58, 4553.43],
-			["2032-12-31", 1723.29, 6276.72],
-			["2033-06-12", 723.28, 7000.00]
+			["2030-12-31", 942.47, 942.47],
+			["2031-12-31", 3528.77, 4471.24],
+			["2032-12-31", 1764.38, 6235.62],
+			["2033-07-12", 764.38, 7000.00]
 		]
 
 		schedules = [[cstr(d.schedule_date), flt(d.depreciation_amount, 2), flt(d.accumulated_depreciation_amount, 2)]

erpnext/regional/india/utils.py

@@ -851,7 +851,7 @@ def get_depreciation_amount(asset, depreciable_value, row):
 		# if its the first depreciation
 		if depreciable_value == asset.gross_purchase_amount:
 			# as per IT act, if the asset is purchased in the 2nd half of fiscal year, then rate is divided by 2
-			diff = date_diff(asset.available_for_use_date, row.depreciation_start_date)
+			diff = date_diff(row.depreciation_start_date, asset.available_for_use_date)
 			if diff <= 180:
 				rate_of_depreciation = rate_of_depreciation / 2
 				frappe.msgprint(