From 2eb4896858f8b08dc86cd31a75e312f6b9a92b05 Mon Sep 17 00:00:00 2001
From: Mike Danese <mikedanese@google.com>
Date: Sat, 26 Mar 2016 22:14:02 -0700
Subject: [PATCH] validate that daemonsets don't have empty selectors on
 creation

---
 pkg/apis/extensions/validation/validation.go      | 3 +++
 pkg/apis/extensions/validation/validation_test.go | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/pkg/apis/extensions/validation/validation.go b/pkg/apis/extensions/validation/validation.go
index b87bff219f2..4981f96c35d 100644
--- a/pkg/apis/extensions/validation/validation.go
+++ b/pkg/apis/extensions/validation/validation.go
@@ -201,6 +201,9 @@ func ValidateDaemonSetSpec(spec *extensions.DaemonSetSpec, fldPath *field.Path)
 	if err == nil && !selector.Matches(labels.Set(spec.Template.Labels)) {
 		allErrs = append(allErrs, field.Invalid(fldPath.Child("template", "metadata", "labels"), spec.Template.Labels, "`selector` does not match template `labels`"))
 	}
+	if spec.Selector != nil && len(spec.Selector.MatchLabels)+len(spec.Selector.MatchExpressions) == 0 {
+		allErrs = append(allErrs, field.Invalid(fldPath.Child("selector"), spec.Selector, "empty selector is not valid for daemonset."))
+	}
 
 	allErrs = append(allErrs, apivalidation.ValidatePodTemplateSpec(&spec.Template, fldPath.Child("template"))...)
 	// Daemons typically run on more than one node, so mark Read-Write persistent disks as invalid.
diff --git a/pkg/apis/extensions/validation/validation_test.go b/pkg/apis/extensions/validation/validation_test.go
index d7e8ebc0bda..5944cc40781 100644
--- a/pkg/apis/extensions/validation/validation_test.go
+++ b/pkg/apis/extensions/validation/validation_test.go
@@ -700,9 +700,16 @@ func TestValidateDaemonSet(t *testing.T) {
 				Template: validPodTemplate.Template,
 			},
 		},
+		"nil selector": {
+			ObjectMeta: api.ObjectMeta{Name: "abc", Namespace: api.NamespaceDefault},
+			Spec: extensions.DaemonSetSpec{
+				Template: validPodTemplate.Template,
+			},
+		},
 		"empty selector": {
 			ObjectMeta: api.ObjectMeta{Name: "abc", Namespace: api.NamespaceDefault},
 			Spec: extensions.DaemonSetSpec{
+				Selector: &unversioned.LabelSelector{},
 				Template: validPodTemplate.Template,
 			},
 		},