SetLabel panics if a local image has no labels about imgutil

[joaopapereira]

@ekcasey I tried to replicate this using the test:

when("image exists and as no labels", func() {
	var (
		img    imgutil.Image
		origID string
	)
	it.Before(func() {
		var err error
		h.CreateImageOnLocal(t, dockerClient, repoName, fmt.Sprintf(`
					FROM scratch
					LABEL repo_name_for_randomisation=%s
				`, repoName), nil)
		img, err = imgutil.NewLocalImage(repoName, dockerClient)
		h.AssertNil(t, err)
		origID = h.ImageID(t, repoName)
	})

	it.After(func() {
		h.AssertNil(t, h.DockerRmi(dockerClient, repoName, origID))
	})

	it("sets label and saves label to docker daemon", func() {
		h.AssertNil(t, img.SetLabel("somekey", "new-val"))
		t.Log("set label")
		label, err := img.Label("somekey")
		h.AssertNil(t, err)
		h.AssertEq(t, label, "new-val")
		t.Log("save label")
		_, err = img.Save()
		h.AssertNil(t, err)

		inspect, _, err := dockerClient.ImageInspectWithRaw(context.TODO(), repoName)
		h.AssertNil(t, err)
		label = inspect.Config.Labels["somekey"]
		h.AssertEq(t, strings.TrimSpace(label), "new-val")
	})
})

and it did not panic, do you think this issue is solved already?

[ekcasey]

@joaopapereira It looks like there is a label on that test image?

[joaopapereira]

These tests pass

when.Focus("image exists without labels", func() {
	it.Before(func() {
		h.CreateImageOnRemote(t, dockerClient, repoName, fmt.Sprintf(`
					FROM scratch
					CMD ["/bin/sh"]
				`), nil)

		var err error
		img, err = imgutil.NewRemoteImage(repoName, authn.DefaultKeychain)
		h.AssertNil(t, err)
	})

	it("sets label on img object", func() {
		h.AssertNil(t, img.SetLabel("mykey", "new-val"))
		label, err := img.Label("mykey")
		h.AssertNil(t, err)
		h.AssertEq(t, label, "new-val")
	})

	it("saves label", func() {
		h.AssertNil(t, img.SetLabel("mykey", "new-val"))
		_, err := img.Save()
		h.AssertNil(t, err)

		// After Pull
		label := remoteLabel(t, dockerClient, repoName, "mykey")
		h.AssertEq(t, "new-val", label)
	})
})

[ekcasey]

@joaopapereira I think it only panics when it is a local image