From 60c9a5ecbdfee06a7b0c95aede7a3247af4eceb5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arda=20G=C3=BC=C3=A7l=C3=BC?= <aguclu@redhat.com>
Date: Thu, 19 Dec 2024 11:35:29 +0300
Subject: [PATCH] Do not attempt to truncate revision history if
 revisionHistoryLimit is negative

---
 .../statefulset/stateful_set_control.go       |  2 +-
 .../statefulset/stateful_set_control_test.go  | 35 +++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/pkg/controller/statefulset/stateful_set_control.go b/pkg/controller/statefulset/stateful_set_control.go
index e8048ed2d91..c5eef3c8ac9 100644
--- a/pkg/controller/statefulset/stateful_set_control.go
+++ b/pkg/controller/statefulset/stateful_set_control.go
@@ -194,7 +194,7 @@ func (ssc *defaultStatefulSetControl) truncateHistory(
 	}
 	historyLen := len(history)
 	historyLimit := int(*set.Spec.RevisionHistoryLimit)
-	if historyLen <= historyLimit {
+	if historyLimit < 0 || historyLen <= historyLimit {
 		return nil
 	}
 	// delete any non-live history to maintain the revision limit.
diff --git a/pkg/controller/statefulset/stateful_set_control_test.go b/pkg/controller/statefulset/stateful_set_control_test.go
index f5bb2a44b1b..b7ad4094cee 100644
--- a/pkg/controller/statefulset/stateful_set_control_test.go
+++ b/pkg/controller/statefulset/stateful_set_control_test.go
@@ -53,6 +53,7 @@ import (
 	"k8s.io/kubernetes/pkg/controller"
 	"k8s.io/kubernetes/pkg/controller/history"
 	"k8s.io/kubernetes/pkg/features"
+	"k8s.io/utils/ptr"
 )
 
 type invariantFunc func(set *apps.StatefulSet, om *fakeObjectManager) error
@@ -2031,6 +2032,13 @@ func TestStatefulSetControlLimitsHistory(t *testing.T) {
 			if err != nil {
 				t.Fatalf("%s: %s", test.name, err)
 			}
+
+			if *set.Spec.RevisionHistoryLimit < 0 {
+				// If the revisionHistoryLimit is negative value, we don't truncate
+				// the revision history and it is incremental.
+				continue
+			}
+
 			if len(revisions) > int(*set.Spec.RevisionHistoryLimit)+2 {
 				t.Fatalf("%s: %d greater than limit %d", test.name, len(revisions), *set.Spec.RevisionHistoryLimit)
 			}
@@ -2052,6 +2060,33 @@ func TestStatefulSetControlLimitsHistory(t *testing.T) {
 				return burst(newStatefulSet(3))
 			},
 		},
+		{
+			name:       "zero revisionHistoryLimit",
+			invariants: assertMonotonicInvariants,
+			initial: func() *apps.StatefulSet {
+				sts := newStatefulSet(3)
+				sts.Spec.RevisionHistoryLimit = ptr.To(int32(0))
+				return sts
+			},
+		},
+		{
+			name:       "negative revisionHistoryLimit",
+			invariants: assertMonotonicInvariants,
+			initial: func() *apps.StatefulSet {
+				sts := newStatefulSet(3)
+				sts.Spec.RevisionHistoryLimit = ptr.To(int32(-2))
+				return sts
+			},
+		},
+		{
+			name:       "positive revisionHistoryLimit",
+			invariants: assertMonotonicInvariants,
+			initial: func() *apps.StatefulSet {
+				sts := newStatefulSet(3)
+				sts.Spec.RevisionHistoryLimit = ptr.To(int32(5))
+				return sts
+			},
+		},
 	}
 	for i := range tests {
 		testFn(t, &tests[i])