fix: skip existing batch number during autogen (backport #31140) (#31144)

* fix: skip existing batch number during autogen (#31140)

* test: correctly check for existing item

* test: batch no for test PR generation

Co-authored-by: Ankush Menat <me@ankush.dev>
Co-authored-by: Ankush Menat <ankush@frappe.io>

erpnext/stock/doctype/batch/batch.py

@@ -87,20 +87,29 @@ def get_batch_naming_series():
 class Batch(Document):
 	def autoname(self):
 		"""Generate random ID for batch if not specified"""
-		if not self.batch_id:
-			create_new_batch, batch_number_series = frappe.db.get_value(
-				"Item", self.item, ["create_new_batch", "batch_number_series"]
-			)
 
-			if create_new_batch:
-				if batch_number_series:
-					self.batch_id = make_autoname(batch_number_series, doc=self)
-				elif batch_uses_naming_series():
-					self.batch_id = self.get_name_from_naming_series()
-				else:
-					self.batch_id = get_name_from_hash()
+		if self.batch_id:
+			self.name = self.batch_id
+			return
+
+		create_new_batch, batch_number_series = frappe.db.get_value(
+			"Item", self.item, ["create_new_batch", "batch_number_series"]
+		)
+
+		if not create_new_batch:
+			frappe.throw(_("Batch ID is mandatory"), frappe.MandatoryError)
+
+		while not self.batch_id:
+			if batch_number_series:
+				self.batch_id = make_autoname(batch_number_series, doc=self)
+			elif batch_uses_naming_series():
+				self.batch_id = self.get_name_from_naming_series()
 			else:
-				frappe.throw(_("Batch ID is mandatory"), frappe.MandatoryError)
+				self.batch_id = get_name_from_hash()
+
+			# User might have manually created a batch with next number
+			if frappe.db.exists("Batch", self.batch_id):
+				self.batch_id = None
 
 		self.name = self.batch_id
 

erpnext/stock/doctype/batch/test_batch.py

@@ -8,6 +8,8 @@ from frappe.utils import cint, flt
 
 from erpnext.accounts.doctype.purchase_invoice.test_purchase_invoice import make_purchase_invoice
 from erpnext.stock.doctype.batch.batch import UnableToSelectBatchError, get_batch_no, get_batch_qty
+from erpnext.stock.doctype.item.test_item import make_item
+from erpnext.stock.doctype.purchase_receipt.test_purchase_receipt import make_purchase_receipt
 from erpnext.stock.get_item_details import get_item_details
 
 
@@ -19,11 +21,13 @@ class TestBatch(FrappeTestCase):
 		)
 
 	@classmethod
-	def make_batch_item(cls, item_name):
+	def make_batch_item(cls, item_name=None):
 		from erpnext.stock.doctype.item.test_item import make_item
 
-		if not frappe.db.exists(item_name):
+		if not frappe.db.exists("Item", item_name):
 			return make_item(item_name, dict(has_batch_no=1, create_new_batch=1, is_stock_item=1))
+		else:
+			return frappe.get_doc("Item", item_name)
 
 	def test_purchase_receipt(self, batch_qty=100):
 		"""Test automated batch creation from Purchase Receipt"""
@@ -237,7 +241,7 @@ class TestBatch(FrappeTestCase):
 		if not use_naming_series:
 			frappe.set_value("Stock Settings", "Stock Settings", "use_naming_series", 0)
 
-	def make_new_batch(self, item_name, batch_id=None, do_not_insert=0):
+	def make_new_batch(self, item_name=None, batch_id=None, do_not_insert=0):
 		batch = frappe.new_doc("Batch")
 		item = self.make_batch_item(item_name)
 		batch.item = item.name
@@ -300,6 +304,26 @@ class TestBatch(FrappeTestCase):
 		details = get_item_details(args)
 		self.assertEqual(details.get("price_list_rate"), 400)
 
+	def test_autocreation_of_batches(self):
+		"""
+		Test if auto created batch no excludes existing batch numbers
+		"""
+		item_code = make_item(
+			properties={
+				"has_batch_no": 1,
+				"batch_number_series": "BATCHEXISTING.###",
+				"create_new_batch": 1,
+			}
+		).name
+
+		manually_created_batch = self.make_new_batch(item_code, batch_id="BATCHEXISTING001").name
+
+		pr_1 = make_purchase_receipt(item_code=item_code, qty=1, batch_no=manually_created_batch)
+		pr_2 = make_purchase_receipt(item_code=item_code, qty=1)
+
+		self.assertNotEqual(pr_1.items[0].batch_no, pr_2.items[0].batch_no)
+		self.assertEqual("BATCHEXISTING002", pr_2.items[0].batch_no)
+
 
 def create_batch(item_code, rate, create_item_price_for_batch):
 	pi = make_purchase_invoice(

erpnext/stock/doctype/purchase_receipt/test_purchase_receipt.py

@@ -1507,6 +1507,7 @@ def make_purchase_receipt(**args):
 			"conversion_factor": args.conversion_factor or 1.0,
 			"stock_qty": flt(qty) * (flt(args.conversion_factor) or 1.0),
 			"serial_no": args.serial_no,
+			"batch_no": args.batch_no,
 			"stock_uom": args.stock_uom or "_Test UOM",
 			"uom": uom,
 			"cost_center": args.cost_center