kustomize transformers to create fields if they are null

api/filters/replicacount/replicacount.go

@@ -39,6 +39,7 @@ func (rc Filter) run(node *yaml.RNode) (*yaml.RNode, error) {
 		FsSlice:    rc.FsSlice,
 		SetValue:   rc.set,
 		CreateKind: yaml.ScalarNode, // replicas is a ScalarNode
+		CreateTag:  yaml.IntTag,
 	})
 	return node, err
 }

api/filters/replicacount/replicacount_test.go

@@ -61,6 +61,41 @@ spec:
 			expected: `
 apiVersion: custom/v1
 kind: Custom
+metadata:
+  name: cus
+spec:
+  template:
+    other: something
+    replicas: 42
+`,
+			filter: Filter{
+				Replica: types.Replica{
+					Name:  "cus",
+					Count: 42,
+				},
+			},
+			fsslice: types.FsSlice{
+				{
+					Path:               "spec/template/replicas",
+					CreateIfNotPresent: true,
+				},
+			},
+		},
+
+		"add_field_null": {
+			input: `
+apiVersion: custom/v1
+kind: Custom
+metadata:
+  name: cus
+spec:
+  template:
+    other: something
+    replicas: null
+`,
+			expected: `
+apiVersion: custom/v1
+kind: Custom
 metadata:
   name: cus
 spec: