From 01de80b092778fd35abd9e2371d54ce0953d4613 Mon Sep 17 00:00:00 2001
From: Alvaro Aleman <aaleman@confluent.io>
Date: Fri, 9 Feb 2024 14:00:57 -0500
Subject: [PATCH] :bug: Fakeclient: Do not consider an apply patch to be a
 strategic merge patch

The fakeclient currently considers an apply patch to be a strategic
merge patch. This is completely wrong, those are different things and
apply patches are not supported in the fakeclientl, because in order to
support them it would need the entire SSA logic which isn't implemented
in upstream yet.
---
 pkg/client/fake/client.go      |  6 ++++--
 pkg/client/fake/client_test.go | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/pkg/client/fake/client.go b/pkg/client/fake/client.go
index 790a1faab1..b90a6ebb8d 100644
--- a/pkg/client/fake/client.go
+++ b/pkg/client/fake/client.go
@@ -947,7 +947,7 @@ func dryPatch(action testing.PatchActionImpl, tracker testing.ObjectTracker) (ru
 		if err := json.Unmarshal(modified, obj); err != nil {
 			return nil, err
 		}
-	case types.StrategicMergePatchType, types.ApplyPatchType:
+	case types.StrategicMergePatchType:
 		mergedByte, err := strategicpatch.StrategicMergePatch(old, action.GetPatch(), obj)
 		if err != nil {
 			return nil, err
@@ -955,8 +955,10 @@ func dryPatch(action testing.PatchActionImpl, tracker testing.ObjectTracker) (ru
 		if err = json.Unmarshal(mergedByte, obj); err != nil {
 			return nil, err
 		}
+	case types.ApplyPatchType:
+		return nil, errors.New("apply patches are not supported in the fake client. Follow https://github.com/kubernetes/kubernetes/issues/115598 for the current status")
 	default:
-		return nil, fmt.Errorf("PatchType is not supported")
+		return nil, fmt.Errorf("%s PatchType is not supported", action.GetPatchType())
 	}
 	return obj, nil
 }
diff --git a/pkg/client/fake/client_test.go b/pkg/client/fake/client_test.go
index d299175ba9..e5487de21a 100644
--- a/pkg/client/fake/client_test.go
+++ b/pkg/client/fake/client_test.go
@@ -359,6 +359,26 @@ var _ = Describe("Fake client", func() {
 			Expect(list.Items).To(ConsistOf(*dep2))
 		})
 
+		It("should reject apply patches, they are not supported in the fake client", func() {
+			By("Creating a new configmap")
+			cm := &corev1.ConfigMap{
+				TypeMeta: metav1.TypeMeta{
+					APIVersion: "v1",
+					Kind:       "ConfigMap",
+				},
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "new-test-cm",
+					Namespace: "ns2",
+				},
+			}
+			err := cl.Create(context.Background(), cm)
+			Expect(err).ToNot(HaveOccurred())
+
+			cm.Data = map[string]string{"foo": "bar"}
+			err = cl.Patch(context.Background(), cm, client.Apply, client.ForceOwnership)
+			Expect(err).To(MatchError(ContainSubstring("apply patches are not supported in the fake client")))
+		})
+
 		It("should be able to Create", func() {
 			By("Creating a new configmap")
 			newcm := &corev1.ConfigMap{