Uniform unmarshal function

api/internal/target/kusttarget.go

@@ -4,7 +4,6 @@
 package target
 
 import (
-	"bytes"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -60,7 +59,7 @@ func (kt *KustTarget) Load() error {
 		return err
 	}
 	var k types.Kustomization
-	err = unmarshal(content, &k)
+	err = k.Unmarshal(content)
 	if err != nil {
 		return err
 	}
@@ -104,16 +103,6 @@ func loadKustFile(ldr ifc.Loader) ([]byte, error) {
 	}
 }
 
-func unmarshal(y []byte, o interface{}) error {
-	j, err := yaml.YAMLToJSON(y)
-	if err != nil {
-		return err
-	}
-	dec := json.NewDecoder(bytes.NewReader(j))
-	dec.DisallowUnknownFields()
-	return dec.Decode(o)
-}
-
 // MakeCustomizedResMap creates a fully customized ResMap
 // per the instructions contained in its kustomiztion instance.
 func (kt *KustTarget) MakeCustomizedResMap() (resmap.ResMap, error) {

api/types/kustomization.go

@@ -3,6 +3,13 @@
 
 package types
 
+import (
+	"bytes"
+	"encoding/json"
+
+	"sigs.k8s.io/yaml"
+)
+
 const (
 	KustomizationVersion  = "kustomize.config.k8s.io/v1beta1"
 	KustomizationKind     = "Kustomization"
@@ -165,3 +172,20 @@ func (k *Kustomization) EnforceFields() []string {
 	}
 	return errs
 }
+
+// Unmarshal replace k with the content in YAML input y
+func (k *Kustomization) Unmarshal(y []byte) error {
+	j, err := yaml.YAMLToJSON(y)
+	if err != nil {
+		return err
+	}
+	dec := json.NewDecoder(bytes.NewReader(j))
+	dec.DisallowUnknownFields()
+	var nk Kustomization
+	err = dec.Decode(&nk)
+	if err != nil {
+		return err
+	}
+	*k = nk
+	return nil
+}

kustomize/internal/commands/kustfile/kustomizationfile.go

@@ -153,7 +153,7 @@ func (mf *kustomizationFile) Read() (*types.Kustomization, error) {
 		return nil, err
 	}
 	var k types.Kustomization
-	err = yaml.Unmarshal(data, &k)
+	err = k.Unmarshal(data)
 	if err != nil {
 		return nil, err
 	}

kustomize/internal/commands/kustfile/kustomizationfile_test.go

@@ -340,3 +340,21 @@ kind: Kustomization
 			string(expected), string(bytes))
 	}
 }
+
+func TestUnknownFieldInKustomization(t *testing.T) {
+	kContent := []byte(`
+foo:
+  bar
+`)
+	fSys := filesys.MakeFsInMemory()
+	testutils_test.WriteTestKustomizationWith(fSys, kContent)
+	mf, err := NewKustomizationFile(fSys)
+	if err != nil {
+		t.Fatalf("Unexpected Error: %v", err)
+	}
+
+	_, err = mf.Read()
+	if err == nil || err.Error() != "json: unknown field \"foo\"" {
+		t.Fatalf("Expect an unknown field error but got: %v", err)
+	}
+}