From 5e62c14c6cf78f1573ac0c878132bfc7c99e8d58 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Wed, 8 Nov 2023 03:16:57 +0000
Subject: [PATCH] fix: avoid overflow in progress bar percentage (#1178)

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/display/progress/status.go  | 13 ++++---
 .../internal/display/progress/status_test.go  | 36 ++++++++++++++++++-
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/cmd/oras/internal/display/progress/status.go b/cmd/oras/internal/display/progress/status.go
index ee2a54501..5c67c2053 100644
--- a/cmd/oras/internal/display/progress/status.go
+++ b/cmd/oras/internal/display/progress/status.go
@@ -55,6 +55,7 @@ type status struct {
 func newStatus() *status {
 	return &status{
 		offset:         -1,
+		total:          humanize.ToBytes(0),
 		lastRenderTime: time.Now(),
 	}
 }
@@ -99,9 +100,6 @@ func (s *status) String(width int) (string, string) {
 	// todo: doesn't support multiline prompt
 	total := uint64(s.descriptor.Size)
 	var percent float64
-	if s.offset >= 0 {
-		percent = float64(s.offset) / float64(total)
-	}
 
 	name := s.descriptor.Annotations["org.opencontainers.image.title"]
 	if name == "" {
@@ -112,10 +110,15 @@ 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 percent {
-	case 1: // 100%, show exact size
+	switch s.done {
+	case true: // 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 {
+			// percentage calculatable
+			percent = float64(s.offset) / float64(total)
+		}
 		offset = fmt.Sprintf("%.2f", humanize.RoundTo(s.total.Size*percent))
 	}
 	right := fmt.Sprintf(" %s/%s %6.2f%% %6s", offset, s.total, percent*100, s.durationString())
diff --git a/cmd/oras/internal/display/progress/status_test.go b/cmd/oras/internal/display/progress/status_test.go
index 38d351872..4ce98bace 100644
--- a/cmd/oras/internal/display/progress/status_test.go
+++ b/cmd/oras/internal/display/progress/status_test.go
@@ -54,7 +54,6 @@ func Test_status_String(t *testing.T) {
 	if err := testutils.OrderedMatch(statusStr+digestStr, " [\x1b[7m\x1b[0m....................]", s.prompt, "application/v.", "0.00/2  B", "0.00%", s.descriptor.Digest.String()); err != nil {
 		t.Error(err)
 	}
-
 	// done
 	s.Update(&status{
 		endTime:    time.Now(),
@@ -67,6 +66,41 @@ func Test_status_String(t *testing.T) {
 	}
 }
 
+func Test_status_String_zeroWitdth(t *testing.T) {
+	// zero status and progress
+	s := newStatus()
+	if status, digest := s.String(console.MinWidth); status != zeroStatus || digest != zeroDigest {
+		t.Errorf("status.String() = %v, %v, want %v, %v", status, digest, zeroStatus, zeroDigest)
+	}
+
+	// not done
+	s.Update(&status{
+		prompt: "test",
+		descriptor: ocispec.Descriptor{
+			MediaType: "application/vnd.oci.empty.oras.test.v1+json",
+			Size:      0,
+			Digest:    "sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+		},
+		startTime: time.Now().Add(-time.Minute),
+		offset:    0,
+		total:     humanize.ToBytes(0),
+	})
+	// not done
+	statusStr, digestStr := s.String(120)
+	if err := testutils.OrderedMatch(statusStr+digestStr, " [\x1b[7m\x1b[0m....................]", s.prompt, s.descriptor.MediaType, "0.00/0  B", "0.00%", s.descriptor.Digest.String()); err != nil {
+		t.Error(err)
+	}
+	// done
+	s.Update(&status{
+		endTime:    time.Now(),
+		offset:     s.descriptor.Size,
+		descriptor: s.descriptor,
+	})
+	statusStr, digestStr = s.String(120)
+	if err := testutils.OrderedMatch(statusStr+digestStr, "✓", s.prompt, s.descriptor.MediaType, "0/0  B", "100.00%", s.descriptor.Digest.String()); err != nil {
+		t.Error(err)
+	}
+}
 func Test_status_durationString(t *testing.T) {
 	// zero duration
 	s := newStatus()