fix(cp): avoid showing empty descriptor in progress bar (#1528)

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
Co-authored-by: Terry Howe <terrylhowe@gmail.com>

cmd/oras/internal/display/status/progress/status.go

@@ -70,7 +70,6 @@ func (s *status) String(width int) (string, string) {
 	}
 	// todo: doesn't support multiline prompt
 	total := uint64(s.descriptor.Size)
-	var percent float64
 
 	name := s.descriptor.Annotations["org.opencontainers.image.title"]
 	if name == "" {
@@ -81,12 +80,18 @@ func (s *status) String(width int) (string, string) {
 	//          mark(1) bar(22) speed(8) action(<=11) name(<=126)        size_per_size(<=13) percent(8) time(>=6)
 	//           └─ digest(72)
 	var offset string
-	switch s.done {
-	case true: // 100%, show exact size
+	var percent float64
+	if s.done {
+		// 100%, show exact size
 		offset = fmt.Sprint(s.total.Size)
 		percent = 1
-	default: // 0% ~ 99%, show 2-digit precision
-		if total != 0 && s.offset >= 0 {
+	} else if total == 0 {
+		// 0 byte, show 100%
+		offset = "0"
+		percent = 1
+	} else {
+		// 0% ~ 99%, show 2-digit precision
+		if s.offset >= 0 {
 			// calculate percentage
 			percent = float64(s.offset) / float64(total)
 		}

cmd/oras/internal/display/status/progress/status_test.go

@@ -89,7 +89,7 @@ func Test_status_String_zeroWidth(t *testing.T) {
 	})
 	// not done
 	statusStr, digestStr := s.String(120)
-	if err := testutils.OrderedMatch(statusStr+digestStr, "\x1b[0m....................]", s.prompt, s.descriptor.MediaType, "0.00/0  B", "0.00%", s.descriptor.Digest.String()); err != nil {
+	if err := testutils.OrderedMatch(statusStr+digestStr, "\x1b[104m                    \x1b[0m", s.prompt, s.descriptor.MediaType, "0/0  B", "100.00%", s.descriptor.Digest.String()); err != nil {
 		t.Error(err)
 	}
 	// done

cmd/oras/internal/display/status/track/target.go

@@ -17,11 +17,13 @@ package track
 
 import (
 	"context"
+	"errors"
 	"io"
 	"os"
 
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"oras.land/oras-go/v2"
+	"oras.land/oras-go/v2/errdef"
 	"oras.land/oras-go/v2/registry"
 	"oras.land/oras/cmd/oras/internal/display/status/progress"
 )
@@ -81,6 +83,10 @@ func (t *graphTarget) Push(ctx context.Context, expected ocispec.Descriptor, con
 	defer r.Close()
 	r.Start()
 	if err := t.GraphTarget.Push(ctx, expected, r); err != nil {
+		if errors.Is(err, errdef.ErrAlreadyExists) {
+			// allowed error types in oras-go oci and memory store
+			r.Done()
+		}
 		return err
 	}
 	r.Done()

cmd/oras/internal/display/status/track/target_test.go

@@ -20,13 +20,15 @@ package track
 import (
 	"bytes"
 	"context"
+	"errors"
 	"io"
 	"testing"
 
 	"github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"oras.land/oras-go/v2"
 	"oras.land/oras-go/v2/content/memory"
+	"oras.land/oras-go/v2/errdef"
 	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras/internal/testutils"
 )
@@ -86,3 +88,44 @@ func Test_referenceGraphTarget_Mount(t *testing.T) {
 	target := graphTarget{GraphTarget: &remote.Repository{}}
 	_ = target.Mount(context.Background(), ocispec.Descriptor{}, "", nil)
 }
+
+func Test_graphTarget_Push_alreadyExists(t *testing.T) {
+	// prepare
+	pty, device, err := testutils.NewPty()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer device.Close()
+	src := memory.New()
+	content := []byte("test")
+	r := bytes.NewReader(content)
+	desc := ocispec.Descriptor{
+		MediaType: "application/octet-stream",
+		Digest:    digest.FromBytes(content),
+		Size:      int64(len(content)),
+	}
+	if err := src.Push(context.Background(), desc, r); err != nil {
+		t.Fatal("Failed to prepare test environment:", err)
+	}
+	// test
+	actionPrompt := "action"
+	donePrompt := "done"
+	target, err := NewTarget(src, actionPrompt, donePrompt, device)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if gt, ok := target.(*graphTarget); ok {
+		if err := gt.Push(context.Background(), desc, r); !errors.Is(err, errdef.ErrAlreadyExists) {
+			t.Fatal("Expected ErrAlreadyExists, got:", err)
+		}
+		if err := gt.manager.Close(); err != nil {
+			t.Fatal(err)
+		}
+	} else {
+		t.Fatal("not testing based on a referenceGraphTarget")
+	}
+	// validate
+	if err = testutils.MatchPty(pty, device, donePrompt, desc.MediaType, "100.00%", desc.Digest.String()); err != nil {
+		t.Fatal(err)
+	}
+}