fix: incorrect cost center in the purchase invoice (backport #37591) (#37609)

* fix: incorrect cost center in the purchase invoice (#37591)

(cherry picked from commit 14b009b093)

# Conflicts:
#	erpnext/accounts/doctype/purchase_invoice/test_purchase_invoice.py

* chore: fix conflicts

---------

Co-authored-by: rohitwaghchaure <rohitw1991@gmail.com>

erpnext/accounts/doctype/purchase_invoice/test_purchase_invoice.py

@@ -1858,6 +1858,30 @@ class TestPurchaseInvoice(FrappeTestCase, StockTestMixin):
 		pi.load_from_db()
 		self.assertFalse(pi.repost_required)
 
+	def test_default_cost_center_for_purchase(self):
+		from erpnext.accounts.doctype.cost_center.test_cost_center import create_cost_center
+
+		for c_center in ["_Test Cost Center Selling", "_Test Cost Center Buying"]:
+			create_cost_center(cost_center_name=c_center)
+
+		item = create_item(
+			"_Test Cost Center Item For Purchase",
+			is_stock_item=1,
+			buying_cost_center="_Test Cost Center Buying - _TC",
+			selling_cost_center="_Test Cost Center Selling - _TC",
+		)
+
+		pi = make_purchase_invoice(
+			item=item.name, qty=1, rate=1000, update_stock=True, do_not_submit=True, cost_center=""
+		)
+
+		pi.items[0].cost_center = ""
+		pi.set_missing_values()
+		pi.calculate_taxes_and_totals()
+		pi.save()
+
+		self.assertEqual(pi.items[0].cost_center, "_Test Cost Center Buying - _TC")
+
 
 def check_gl_entries(
 	doc,

erpnext/stock/doctype/item/test_item.py

@@ -893,6 +893,8 @@ def create_item(
 	opening_stock=0,
 	is_fixed_asset=0,
 	asset_category=None,
+	buying_cost_center=None,
+	selling_cost_center=None,
 	company="_Test Company",
 ):
 	if not frappe.db.exists("Item", item_code):
@@ -910,7 +912,15 @@ def create_item(
 		item.is_purchase_item = is_purchase_item
 		item.is_customer_provided_item = is_customer_provided_item
 		item.customer = customer or ""
-		item.append("item_defaults", {"default_warehouse": warehouse, "company": company})
+		item.append(
+			"item_defaults",
+			{
+				"default_warehouse": warehouse,
+				"company": company,
+				"selling_cost_center": selling_cost_center,
+				"buying_cost_center": buying_cost_center,
+			},
+		)
 		item.save()
 	else:
 		item = frappe.get_doc("Item", item_code)

erpnext/stock/get_item_details.py

@@ -771,6 +771,12 @@ def get_default_cost_center(args, item=None, item_group=None, brand=None, compan
 			data = frappe.get_attr(path)(args.get("item_code"), company)
 
 			if data and (data.selling_cost_center or data.buying_cost_center):
+				if args.get("customer") and data.selling_cost_center:
+					return data.selling_cost_center
+
+				elif args.get("supplier") and data.buying_cost_center:
+					return data.buying_cost_center
+
 				return data.selling_cost_center or data.buying_cost_center
 
 	if not cost_center and args.get("cost_center"):