fix: warning message for negative stock (backport #42683) (#42709)

* fix: warning message for negative stock (#42683)

(cherry picked from commit deccb007c1)

# Conflicts:
#	erpnext/stock/stock_ledger.py

* chore: fix conflicts

---------

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

erpnext/stock/stock_ledger.py

@@ -4,10 +4,10 @@
 import json
 
 import frappe
-from frappe import _
+from frappe import _, bold
 from frappe.model.meta import get_field_precision
 from frappe.query_builder.functions import Sum
-from frappe.utils import cint, cstr, flt, get_link_to_form, getdate, now, nowdate
+from frappe.utils import cint, cstr, flt, format_date, get_link_to_form, getdate, now, nowdate
 
 import erpnext
 from erpnext.stock.doctype.bin.bin import update_qty as update_bin_qty
@@ -542,11 +542,31 @@ class update_entries_after:
 
 		return self.distinct_item_warehouses[key].dependent_voucher_detail_nos
 
+	def validate_previous_sle_qty(self, sle):
+		previous_sle = self.data[sle.warehouse].previous_sle
+		if previous_sle and previous_sle.get("qty_after_transaction") < 0 and sle.get("actual_qty") > 0:
+			frappe.msgprint(
+				_(
+					"The stock for the item {0} in the {1} warehouse was negative on the {2}. You should create a positive entry {3} before the date {4} and time {5} to post the correct valuation rate. For more details, please read the <a href='https://docs.erpnext.com/docs/user/manual/en/stock-adjustment-cogs-with-negative-stock'>documentation<a>."
+				).format(
+					bold(sle.item_code),
+					bold(sle.warehouse),
+					bold(format_date(previous_sle.posting_date)),
+					sle.voucher_no,
+					bold(format_date(previous_sle.posting_date)),
+					bold(previous_sle.posting_time),
+				),
+				title=_("Warning on Negative Stock"),
+				indicator="blue",
+			)
+
 	def process_sle(self, sle):
 		from erpnext.stock.doctype.serial_no.serial_no import get_serial_nos
 
 		# previous sle data for this warehouse
 		self.wh_data = self.data[sle.warehouse]
+
+		self.validate_previous_sle_qty(sle)
 		self.affected_transactions.add((sle.voucher_type, sle.voucher_no))
 
 		if (sle.serial_no and not self.via_landed_cost_voucher) or not cint(self.allow_negative_stock):