Merge pull request #53164 from enisoc/rc-rs-conversion

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Fix RC/RS conversion

This fixes some round-trip information loss when representing an RC as an RS. I want to use these conversions in #49429 to eliminate the maintenance burden of duplicated RC code.

@kubernetes/sig-apps-pr-reviews

staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/BUILD

@@ -93,3 +93,13 @@ filegroup(
     srcs = ["generated.proto"],
     visibility = ["//visibility:public"],
 )
+
+go_test(
+    name = "go_default_xtest",
+    srcs = ["conversion_test.go"],
+    importpath = "k8s.io/apimachinery/pkg/apis/meta/v1_test",
+    deps = [
+        "//vendor/k8s.io/apimachinery/pkg/api/equality:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+    ],
+)

staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/conversion.go

@@ -252,7 +252,6 @@ func Convert_map_to_unversioned_LabelSelector(in *map[string]string, out *LabelS
 	if in == nil {
 		return nil
 	}
-	out = new(LabelSelector)
 	for labelKey, labelValue := range *in {
 		AddLabelToSelector(out, labelKey, labelValue)
 	}

staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/conversion_test.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1_test
+
+import (
+	"testing"
+
+	apiequality "k8s.io/apimachinery/pkg/api/equality"
+	"k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestMapToLabelSelectorRoundTrip(t *testing.T) {
+	// We should be able to round-trip a map-only selector through LabelSelector.
+	inputs := []map[string]string{
+		nil,
+		{},
+		{"one": "foo"},
+		{"one": "foo", "two": "bar"},
+	}
+	for _, in := range inputs {
+		ls := &v1.LabelSelector{}
+		if err := v1.Convert_map_to_unversioned_LabelSelector(&in, ls, nil); err != nil {
+			t.Errorf("Convert_map_to_unversioned_LabelSelector(%#v): %v", in, err)
+			continue
+		}
+		out := map[string]string{}
+		if err := v1.Convert_unversioned_LabelSelector_to_map(ls, &out, nil); err != nil {
+			t.Errorf("Convert_unversioned_LabelSelector_to_map(%#v): %v", ls, err)
+			continue
+		}
+		if !apiequality.Semantic.DeepEqual(in, out) {
+			t.Errorf("map-selector conversion round-trip failed: got %v; want %v", out, in)
+		}
+	}
+}