From 553336fa6fdb22176433c9ff22f4ba53f92babc6 Mon Sep 17 00:00:00 2001
From: Mihir Kandoi <kandoimihir@gmail.com>
Date: Thu, 23 Jul 2026 13:07:51 +0530
Subject: [PATCH] fix: resolve or require operation_id server-side

---
 .../doctype/job_card/job_card.py              | 20 ++++++++++++++
 .../doctype/job_card/test_job_card.py         | 27 +++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/erpnext/manufacturing/doctype/job_card/job_card.py b/erpnext/manufacturing/doctype/job_card/job_card.py
index d69d8346f1d..4437a0d89e7 100644
--- a/erpnext/manufacturing/doctype/job_card/job_card.py
+++ b/erpnext/manufacturing/doctype/job_card/job_card.py
@@ -163,6 +163,7 @@ class JobCard(Document):
 		self.validate_time_logs()
 		self.validate_on_hold()
 		self.set_status()
+		self.set_operation_id()
 		self.validate_sequence_id()
 		self.set_sub_operations()
 		self.update_sub_operation_status()
@@ -1338,6 +1339,25 @@ class JobCard(Document):
 		if not self.wip_warehouse:
 			self.wip_warehouse = frappe.get_cached_value("Company", self.company, "default_wip_warehouse")
 
+	def set_operation_id(self):
+		if self.operation_id or not (self.work_order and self.operation):
+			return
+
+		operation_rows = frappe.get_all(
+			"Work Order Operation",
+			filters={"parent": self.work_order, "operation": self.operation},
+			pluck="name",
+		)
+
+		if len(operation_rows) == 1:
+			self.operation_id = operation_rows[0]
+		elif operation_rows and self.docstatus == 0:
+			frappe.throw(
+				_(
+					"Operation {0} is added multiple times in the work order {1}. Please select the operation row."
+				).format(bold(self.operation), get_link_to_form("Work Order", self.work_order))
+			)
+
 	@frappe.whitelist()
 	def pause_job(self, **kwargs):
 		frappe.has_permission("Job Card", "write", doc=self, throw=True)
diff --git a/erpnext/manufacturing/doctype/job_card/test_job_card.py b/erpnext/manufacturing/doctype/job_card/test_job_card.py
index 9acbe89c34e..32f84c9943a 100644
--- a/erpnext/manufacturing/doctype/job_card/test_job_card.py
+++ b/erpnext/manufacturing/doctype/job_card/test_job_card.py
@@ -148,6 +148,33 @@ class TestJobCard(ERPNextTestSuite):
 		)
 		self.assertRaises(frappe.ValidationError, job_card_doc.submit)
 
+	def test_set_operation_id(self):
+		work_order = make_wo_order_test_record(item="_Test FG Item 2", qty=2, do_not_submit=1)
+		operation_row = work_order.operations[0]
+
+		job_card = frappe.new_doc("Job Card")
+		job_card.work_order = work_order.name
+		job_card.operation = operation_row.operation
+		job_card.set_operation_id()
+		self.assertEqual(job_card.operation_id, operation_row.name)
+
+		work_order.append(
+			"operations",
+			{
+				"operation": operation_row.operation,
+				"workstation": operation_row.workstation,
+				"time_in_mins": operation_row.time_in_mins,
+				"hour_rate": operation_row.hour_rate,
+				"sequence_id": work_order.operations[-1].sequence_id,
+			},
+		)
+		work_order.save()
+
+		job_card = frappe.new_doc("Job Card")
+		job_card.work_order = work_order.name
+		job_card.operation = operation_row.operation
+		self.assertRaises(frappe.ValidationError, job_card.set_operation_id)
+
 	def test_job_card_with_different_work_station(self):
 		job_cards = frappe.get_all(
 			"Job Card",