put namespace objects first in the output

pkg/resmap/idslice.go

@@ -20,6 +20,7 @@ import (
 	"sort"
 
 	"github.com/kubernetes-sigs/kustomize/pkg/resource"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 )
 
 // IdSlice implements the sort interface.
@@ -31,7 +32,17 @@ func (a IdSlice) Len() int      { return len(a) }
 func (a IdSlice) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
 func (a IdSlice) Less(i, j int) bool {
 	if a[i].Gvk().String() != a[j].Gvk().String() {
-		return a[i].Gvk().String() < a[j].Gvk().String()
+		return gvkLess(a[i].Gvk(), a[j].Gvk())
 	}
 	return a[i].Name() < a[j].Name()
 }
+
+func gvkLess(i, j schema.GroupVersionKind) bool {
+	if i.Kind == "Namespace" {
+		return true
+	} else if j.Kind == "Namespace" {
+		return false
+	} else {
+		return i.String() < j.String()
+	}
+}

pkg/resmap/idslice_test.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2018 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 resmap
+
+import (
+	"reflect"
+	"sort"
+	"testing"
+
+	"github.com/kubernetes-sigs/kustomize/pkg/resource"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+func TestLess(t *testing.T) {
+	ids := IdSlice{
+		resource.NewResId(schema.GroupVersionKind{Kind: "ConfigMap"}, "cm"),
+		resource.NewResId(schema.GroupVersionKind{Kind: "Pod"}, "pod"),
+		resource.NewResId(schema.GroupVersionKind{Kind: "Namespace"}, "ns1"),
+		resource.NewResId(schema.GroupVersionKind{Kind: "Namespace"}, "ns2"),
+	}
+	expected := IdSlice{
+		resource.NewResId(schema.GroupVersionKind{Kind: "Namespace"}, "ns1"),
+		resource.NewResId(schema.GroupVersionKind{Kind: "Namespace"}, "ns2"),
+		resource.NewResId(schema.GroupVersionKind{Kind: "ConfigMap"}, "cm"),
+		resource.NewResId(schema.GroupVersionKind{Kind: "Pod"}, "pod"),
+	}
+	sort.Sort(ids)
+	if !reflect.DeepEqual(ids, expected) {
+		t.Fatalf("expected %+v but got %+v", expected, ids)
+	}
+}