From 994a2b10363dab995109d172a8ee772616d2c901 Mon Sep 17 00:00:00 2001
From: Cedric Le Roux <leroux.cedric@gmail.com>
Date: Wed, 14 Feb 2024 08:14:11 -0800
Subject: [PATCH] client: fixed a bug where corrupt client state could panic
 the client (#19972)

---
 .changelog/19972.txt     | 3 +++
 client/client_test.go    | 8 ++++++++
 nomad/structs/structs.go | 3 +++
 3 files changed, 14 insertions(+)
 create mode 100644 .changelog/19972.txt

diff --git a/.changelog/19972.txt b/.changelog/19972.txt
new file mode 100644
index 000000000..92c9a7fd2
--- /dev/null
+++ b/.changelog/19972.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+client: Fixed a bug where corrupt client state could panic the client
+```
diff --git a/client/client_test.go b/client/client_test.go
index 0fcb0c98a..d001dde32 100644
--- a/client/client_test.go
+++ b/client/client_test.go
@@ -1876,6 +1876,14 @@ func TestClient_hasLocalState(t *testing.T) {
 
 	c.stateDB = cstate.NewMemDB(c.logger)
 
+	t.Run("nil Job", func(t *testing.T) {
+		alloc := mock.BatchAlloc()
+		alloc.Job = nil
+		c.stateDB.PutAllocation(alloc)
+
+		must.False(t, c.hasLocalState(alloc))
+	})
+
 	t.Run("plain alloc", func(t *testing.T) {
 		alloc := mock.BatchAlloc()
 		c.stateDB.PutAllocation(alloc)
diff --git a/nomad/structs/structs.go b/nomad/structs/structs.go
index b64961fcb..971356050 100644
--- a/nomad/structs/structs.go
+++ b/nomad/structs/structs.go
@@ -4770,6 +4770,9 @@ func (j *Job) Warnings() error {
 
 // LookupTaskGroup finds a task group by name
 func (j *Job) LookupTaskGroup(name string) *TaskGroup {
+	if j == nil {
+		return nil
+	}
 	for _, tg := range j.TaskGroups {
 		if tg.Name == name {
 			return tg