fix analyzer warnings (#412)

* remove unused codes (structcheck)(varcheck)

* add error handling (errcheck)

* add error handling (ineffassign)

* fix lint errors (golint)

pkg/kn/commands/service/update_test.go

@@ -143,7 +143,10 @@ func TestServiceUpdateImageSync(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	err = servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	action, updated, output, err := fakeServiceUpdate(orig, []string{
 		"service", "update", "foo", "--image", "gcr.io/foo/quux:xyzzy", "--namespace", "bar"}, true)
@@ -166,7 +169,10 @@ func TestServiceUpdateImage(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+		err = servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+		if err != nil {
+			t.Fatal(err)
+		}
 
 		action, updated, output, err := fakeServiceUpdate(orig, []string{
 			"service", "update", "foo", "--image", "gcr.io/foo/quux:xyzzy", "--namespace", "bar", "--async"}, false)
@@ -371,7 +377,10 @@ func TestServiceUpdatePinsToDigestWhenAsked(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	err = servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	action, updated, _, err := fakeServiceUpdate(orig, []string{
 		"service", "update", "foo", "-e", "TARGET=Awesome", "--lock-to-digest", "--async"}, false)
@@ -396,7 +405,10 @@ func TestServiceUpdatePinsToDigestWhenPreviouslyDidSo(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	err = servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	action, updated, _, err := fakeServiceUpdate(orig, []string{
 		"service", "update", "foo", "-e", "TARGET=Awesome", "--async"}, false)
@@ -421,7 +433,10 @@ func TestServiceUpdateDoesntPinToDigestWhenUnAsked(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	err = servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	action, updated, _, err := fakeServiceUpdate(orig, []string{
 		"service", "update", "foo", "-e", "TARGET=Awesome", "--no-lock-to-digest", "--async"}, false)
@@ -443,12 +458,15 @@ func TestServiceUpdateDoesntPinToDigestWhenPreviouslyDidnt(t *testing.T) {
 	orig := newEmptyService()
 
 	template, err := servinglib.RevisionTemplateOfService(orig)
-	delete(template.Annotations, servinglib.UserImageAnnotationKey)
 	if err != nil {
 		t.Fatal(err)
 	}
+	delete(template.Annotations, servinglib.UserImageAnnotationKey)
 
-	servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	err = servinglib.UpdateImage(template, "gcr.io/foo/bar:baz")
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	action, updated, _, err := fakeServiceUpdate(orig, []string{
 		"service", "update", "foo", "-e", "TARGET=Awesome", "--async"}, false)

pkg/kn/commands/testing_helper.go

@@ -39,8 +39,6 @@ var (
 	output    string
 
 	readFile, writeFile *os.File
-
-	origArgs []string
 )
 
 // CreateTestKnCommand helper for creating test commands

pkg/kn/commands/types_test.go

@@ -106,8 +106,6 @@ type typeTestCase struct {
 
 func TestGetClientConfig(t *testing.T) {
 	multiConfigs := fmt.Sprintf("%s%s%s", "/testing/assets/kube-config-01.yml", string(os.PathListSeparator), "/testing/assets/kube-config-02.yml")
-
-	multiConfigs = multiConfigs
 	for _, tc := range []typeTestCase{
 		{
 			"",

pkg/printers/tablegenerator.go

@@ -38,7 +38,6 @@ type PrintHandler interface {
 type handlerEntry struct {
 	columnDefinitions []metav1beta1.TableColumnDefinition
 	printFunc         reflect.Value
-	args              []reflect.Value
 }
 
 // HumanReadablePrinter is an implementation of ResourcePrinter which attempts to provide

pkg/serving/config_changes.go

@@ -165,11 +165,15 @@ func SetUserImageAnnot(template *servingv1alpha1.RevisionTemplateSpec) {
 
 // FreezeImageToDigest sets the image on the template to the image digest of the base revision.
 func FreezeImageToDigest(template *servingv1alpha1.RevisionTemplateSpec, baseRevision *servingv1alpha1.Revision) error {
-	currentContainer, err := ContainerOfRevisionTemplate(template)
-
 	if baseRevision == nil {
 		return nil
 	}
+
+	currentContainer, err := ContainerOfRevisionTemplate(template)
+	if err != nil {
+		return err
+	}
+
 	baseContainer, err := ContainerOfRevisionSpec(&baseRevision.Spec)
 	if err != nil {
 		return err

pkg/serving/v1alpha1/client_test.go

@@ -422,9 +422,8 @@ func TestGetBaseRevision(t *testing.T) {
 		if c.foundRevisionImage != "" {
 			revision.Spec.Containers[0].Image = c.foundRevisionImage
 			return true, revision, nil
-		} else {
-			return true, nil, errors.NewNotFound(v1alpha1.Resource("revision"), name)
 		}
+		return true, nil, errors.NewNotFound(v1alpha1.Resource("revision"), name)
 	})
 	for _, c = range cases {
 		service := v1alpha1.Service{}