From bab77cd33848aafe1e3bd4655c98c962c7a8ee88 Mon Sep 17 00:00:00 2001
From: Ismail Alidzhikov <9372594+ialidzhikov@users.noreply.github.com>
Date: Tue, 11 Feb 2025 17:22:11 +0200
Subject: [PATCH] Address review feedback from plkokanov

---
 vertical-pod-autoscaler/pkg/utils/vpa/capping.go      | 4 +++-
 vertical-pod-autoscaler/pkg/utils/vpa/capping_test.go | 5 +++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/vertical-pod-autoscaler/pkg/utils/vpa/capping.go b/vertical-pod-autoscaler/pkg/utils/vpa/capping.go
index 080dc8de68c7..815caa37048c 100644
--- a/vertical-pod-autoscaler/pkg/utils/vpa/capping.go
+++ b/vertical-pod-autoscaler/pkg/utils/vpa/capping.go
@@ -200,7 +200,9 @@ func applyVPAPolicyForContainer(containerName string,
 
 	var maxAllowed apiv1.ResourceList
 	if containerPolicy != nil {
-		maxAllowed = containerPolicy.MaxAllowed
+		// Deep copy containerPolicy.MaxAllowed as maxAllowed can later on be merged with globalMaxAllowed.
+		// Deep copy is needed to prevent unwanted modifications to containerPolicy.MaxAllowed.
+		maxAllowed = containerPolicy.MaxAllowed.DeepCopy()
 	}
 	if maxAllowed == nil {
 		maxAllowed = globalMaxAllowed
diff --git a/vertical-pod-autoscaler/pkg/utils/vpa/capping_test.go b/vertical-pod-autoscaler/pkg/utils/vpa/capping_test.go
index 825f31356b95..9fd890cb4e5e 100644
--- a/vertical-pod-autoscaler/pkg/utils/vpa/capping_test.go
+++ b/vertical-pod-autoscaler/pkg/utils/vpa/capping_test.go
@@ -569,9 +569,14 @@ func TestApplyVPAPolicy(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.Name, func(t *testing.T) {
+			resourcePolicyCopy := tt.ResourcePolicy.DeepCopy()
+
 			actual, err := ApplyVPAPolicy(tt.PodRecommendation, tt.ResourcePolicy, tt.GlobalMaxAllowed)
 			assert.Nil(t, err)
 			assert.Equal(t, tt.Expected, actual)
+
+			// Make sure that the func does not have a side affect and does not modify the passed resource policy.
+			assert.Equal(t, resourcePolicyCopy, tt.ResourcePolicy)
 		})
 	}
 }