From 5dd63fdb713a2b0869a8257705775d45d86639e7 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 28 Dec 2023 08:09:12 +0000
Subject: [PATCH 01/42] chore(ux): show registry error and hint for dockehub

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 34 ++++++++++++++++++++++++++++++
 cmd/oras/internal/option/target.go | 33 +++++++++++++++++++++++++++++
 cmd/oras/root/pull.go              |  8 +++----
 3 files changed, 71 insertions(+), 4 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index b93144428..cd0507dcc 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -16,10 +16,12 @@ limitations under the License.
 package errors
 
 import (
+	"errors"
 	"fmt"
 
 	"github.com/spf13/cobra"
 	"oras.land/oras-go/v2/registry"
+	"oras.land/oras-go/v2/registry/remote/errcode"
 )
 
 // Error is the error type for CLI error messaging.
@@ -60,6 +62,38 @@ func CheckArgs(checker func(args []string) (bool, string), Usage string) cobra.P
 	}
 }
 
+func handleRegistryErr(err error, cmd *cobra.Command) *errcode.ErrorResponse {
+	var errResp *errcode.ErrorResponse
+	if errors.As(err, &errResp) {
+		cmd.SetErrPrefix("Error response from registry:")
+	}
+	return errResp
+}
+
+// Handle handles error during cmd execution.
+func Handle(cmd *cobra.Command, recommend func(err error, callPath string) string) *cobra.Command {
+	runE := cmd.RunE
+	cmd.RunE = func(cmd *cobra.Command, args []string) error {
+		err := runE(cmd, args)
+		if err == nil {
+			return nil
+		}
+
+		errResp := handleRegistryErr(err, cmd)
+		if errResp == nil {
+			return nil
+		}
+
+		// 2. return scrubbed error
+		return &Error{
+			Err:            errResp.Errors,
+			Recommendation: recommend(errResp, cmd.CommandPath()),
+		}
+	}
+
+	return cmd
+}
+
 // NewErrEmptyTagOrDigest creates a new error based on the reference string.
 func NewErrEmptyTagOrDigest(ref registry.Reference) error {
 	return NewErrEmptyTagOrDigestStr(ref.String())
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index a2f0e6995..25cb0cd93 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -32,6 +32,7 @@ import (
 	"oras.land/oras-go/v2/content/oci"
 	"oras.land/oras-go/v2/registry"
 	"oras.land/oras-go/v2/registry/remote"
+	"oras.land/oras-go/v2/registry/remote/errcode"
 	oerrors "oras.land/oras/cmd/oras/internal/errors"
 	"oras.land/oras/cmd/oras/internal/fileref"
 )
@@ -239,6 +240,30 @@ func (opts *Target) EnsureReferenceNotEmpty() error {
 	return nil
 }
 
+// Recommend returns a recommendation for known errors.
+func (opts *Target) Recommend(err error, callPath string) string {
+	if opts.IsOCILayout {
+		return ""
+	}
+	ref, parseErr := registry.ParseReference(opts.Path)
+	if parseErr != nil {
+		// this should not happen
+		return ""
+	}
+
+	// docker.io/xxx -> docker.io/library/xxx
+	if respErr, ok := err.(*errcode.ErrorResponse); ok {
+		if ref.Registry == "docker.io" && respErr.URL.Host == ref.Host() {
+			if !strings.Contains(ref.Repository, "/") {
+				ref.Repository = "library/" + ref.Repository
+				return fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", callPath, ref)
+			}
+		}
+	}
+
+	return ""
+}
+
 // BinaryTarget struct contains flags and arguments specifying two registries or
 // image layouts.
 type BinaryTarget struct {
@@ -269,3 +294,11 @@ func (opts *BinaryTarget) Parse() error {
 	opts.To.resolveFlag = append(opts.resolveFlag, opts.To.resolveFlag...)
 	return Parse(opts)
 }
+
+// Recommend returns a recommendation for known errors.
+func (opts *BinaryTarget) Recommend(err error, callPath string) string {
+	if recommendation := opts.From.Recommend(err, callPath); recommendation != "" {
+		return recommendation
+	}
+	return opts.To.Recommend(err, callPath)
+}
diff --git a/cmd/oras/root/pull.go b/cmd/oras/root/pull.go
index bf39e05e6..b85d2f8f6 100644
--- a/cmd/oras/root/pull.go
+++ b/cmd/oras/root/pull.go
@@ -92,7 +92,7 @@ Example - Pull artifact files from an OCI layout archive 'layout.tar':
 			return option.Parse(&opts)
 		},
 		RunE: func(cmd *cobra.Command, args []string) error {
-			return runPull(cmd.Context(), opts)
+			return runPull(cmd.Context(), &opts)
 		},
 	}
 
@@ -103,10 +103,10 @@ Example - Pull artifact files from an OCI layout archive 'layout.tar':
 	cmd.Flags().StringVarP(&opts.ManifestConfigRef, "config", "", "", "output manifest config file")
 	cmd.Flags().IntVarP(&opts.concurrency, "concurrency", "", 3, "concurrency level")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Handle(cmd, opts.Target.Recommend)
 }
 
-func runPull(ctx context.Context, opts pullOptions) error {
+func runPull(ctx context.Context, opts *pullOptions) error {
 	ctx, logger := opts.WithContext(ctx)
 	// Copy Options
 	copyOptions := oras.DefaultCopyOptions
@@ -133,7 +133,7 @@ func runPull(ctx context.Context, opts pullOptions) error {
 	dst.AllowPathTraversalOnWrite = opts.PathTraversal
 	dst.DisableOverwrite = opts.KeepOldFiles
 
-	desc, layerSkipped, err := doPull(ctx, src, dst, copyOptions, &opts)
+	desc, layerSkipped, err := doPull(ctx, src, dst, copyOptions, opts)
 	if err != nil {
 		if errors.Is(err, file.ErrPathTraversalDisallowed) {
 			err = fmt.Errorf("%s: %w", "use flag --allow-path-traversal to allow insecurely pulling files outside of working directory", err)

From 69941672ddd80335ef8ef24ab556c1f0085a1561 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 28 Dec 2023 08:11:14 +0000
Subject: [PATCH 02/42] code clean

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index cd0507dcc..72dc68f37 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -79,12 +79,13 @@ func Handle(cmd *cobra.Command, recommend func(err error, callPath string) strin
 			return nil
 		}
 
+		// 1. try extract registry error
 		errResp := handleRegistryErr(err, cmd)
 		if errResp == nil {
 			return nil
 		}
 
-		// 2. return scrubbed error
+		// 2.recommend & return scrubbed error
 		return &Error{
 			Err:            errResp.Errors,
 			Recommendation: recommend(errResp, cmd.CommandPath()),

From 3c10c7dd6102fb48f56487e2776df0220af193cf Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 29 Dec 2023 07:12:55 +0000
Subject: [PATCH 03/42] support not found error

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 41 ++++++++++----------
 cmd/oras/internal/option/target.go | 61 +++++++++++++++++++++++-------
 cmd/oras/root/pull.go              |  2 +-
 3 files changed, 69 insertions(+), 35 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index 72dc68f37..ceb28d0fa 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -16,14 +16,15 @@ limitations under the License.
 package errors
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/spf13/cobra"
 	"oras.land/oras-go/v2/registry"
-	"oras.land/oras-go/v2/registry/remote/errcode"
 )
 
+// RegistryErrorPrefix is the commandline prefix for errors from registry.
+const RegistryErrorPrefix = "Error response from registry:"
+
 // Error is the error type for CLI error messaging.
 type Error struct {
 	Err            error
@@ -62,36 +63,36 @@ func CheckArgs(checker func(args []string) (bool, string), Usage string) cobra.P
 	}
 }
 
-func handleRegistryErr(err error, cmd *cobra.Command) *errcode.ErrorResponse {
-	var errResp *errcode.ErrorResponse
-	if errors.As(err, &errResp) {
-		cmd.SetErrPrefix("Error response from registry:")
-	}
-	return errResp
+// Handler handles error during cmd execution.
+type Handler interface {
+	// Handle handles error during cmd execution.
+	// If returned processor is nil, error requires no further processing.
+	Handle(err error, cmd *cobra.Command) (Processor, error)
+}
+
+// Processor processes error.
+type Processor interface {
+	Process(error) error
+	Recommend(err error, callPath string) string
 }
 
-// Handle handles error during cmd execution.
-func Handle(cmd *cobra.Command, recommend func(err error, callPath string) string) *cobra.Command {
+// Command returns an error-handled for cobra command.
+func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
 	runE := cmd.RunE
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
 		err := runE(cmd, args)
 		if err == nil {
 			return nil
 		}
-
-		// 1. try extract registry error
-		errResp := handleRegistryErr(err, cmd)
-		if errResp == nil {
-			return nil
+		processor, err := handler.Handle(err, cmd)
+		if processor == nil {
+			return err
 		}
-
-		// 2.recommend & return scrubbed error
 		return &Error{
-			Err:            errResp.Errors,
-			Recommendation: recommend(errResp, cmd.CommandPath()),
+			Err:            processor.Process(err),
+			Recommendation: processor.Recommend(err, cmd.CommandPath()),
 		}
 	}
-
 	return cmd
 }
 
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index 25cb0cd93..cfa5b0bf5 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -21,15 +21,18 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
+	"net/http"
 	"os"
 	"strings"
 	"sync"
 
 	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"oras.land/oras-go/v2"
 	"oras.land/oras-go/v2/content"
 	"oras.land/oras-go/v2/content/oci"
+	"oras.land/oras-go/v2/errdef"
 	"oras.land/oras-go/v2/registry"
 	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras-go/v2/registry/remote/errcode"
@@ -44,6 +47,7 @@ const (
 
 // Target struct contains flags and arguments specifying one registry or image
 // layout.
+// Target implements errors.Handler and errors.Processor interface.
 type Target struct {
 	Remote
 	RawReference string
@@ -240,32 +244,61 @@ func (opts *Target) EnsureReferenceNotEmpty() error {
 	return nil
 }
 
+// Handle handles error during cmd execution.
+func (opts *Target) Handle(err error, cmd *cobra.Command) (oerrors.Processor, error) {
+	// handle registry error
+	if opts.IsOCILayout {
+		return nil, err
+	}
+
+	// handle not found error from registry
+	if errors.Is(err, errdef.ErrNotFound) {
+		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
+		return opts, err
+	}
+
+	// handle error response
+	var errResp *errcode.ErrorResponse
+	if errors.As(err, &errResp) {
+		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
+		return opts, errResp
+	}
+	return opts, err
+}
+
+// Process returns a scrubbed error.
+func (opts *Target) Process(err error) error {
+	if errResp, ok := err.(*errcode.ErrorResponse); ok {
+		// remove HTTP related info
+		return errResp.Errors
+	}
+	return err
+}
+
 // Recommend returns a recommendation for known errors.
 func (opts *Target) Recommend(err error, callPath string) string {
 	if opts.IsOCILayout {
 		return ""
 	}
-	ref, parseErr := registry.ParseReference(opts.Path)
+	ref, parseErr := registry.ParseReference(opts.RawReference)
 	if parseErr != nil {
 		// this should not happen
 		return ""
 	}
 
-	// docker.io/xxx -> docker.io/library/xxx
-	if respErr, ok := err.(*errcode.ErrorResponse); ok {
-		if ref.Registry == "docker.io" && respErr.URL.Host == ref.Host() {
-			if !strings.Contains(ref.Repository, "/") {
-				ref.Repository = "library/" + ref.Repository
-				return fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", callPath, ref)
-			}
+	if respErr, ok := err.(*errcode.ErrorResponse); ok && ref.Registry == "docker.io" && respErr.URL.Host == ref.Host() && respErr.StatusCode == http.StatusUnauthorized {
+		if !strings.Contains(ref.Repository, "/") {
+			// docker.io/xxx -> docker.io/library/xxx
+			ref.Repository = "library/" + ref.Repository
+			return fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", callPath, ref)
 		}
 	}
-
 	return ""
 }
 
 // BinaryTarget struct contains flags and arguments specifying two registries or
 // image layouts.
+// BinaryTarget implements errors.Handler interface.
 type BinaryTarget struct {
 	From        Target
 	To          Target
@@ -295,10 +328,10 @@ func (opts *BinaryTarget) Parse() error {
 	return Parse(opts)
 }
 
-// Recommend returns a recommendation for known errors.
-func (opts *BinaryTarget) Recommend(err error, callPath string) string {
-	if recommendation := opts.From.Recommend(err, callPath); recommendation != "" {
-		return recommendation
+// Handle handles error during cmd execution.
+func (opts *BinaryTarget) Handle(err error, cmd *cobra.Command) (oerrors.Processor, error) {
+	if processor, err := opts.From.Handle(err, cmd); processor != nil {
+		return processor, err
 	}
-	return opts.To.Recommend(err, callPath)
+	return opts.To.Handle(err, cmd)
 }
diff --git a/cmd/oras/root/pull.go b/cmd/oras/root/pull.go
index b85d2f8f6..d59343002 100644
--- a/cmd/oras/root/pull.go
+++ b/cmd/oras/root/pull.go
@@ -103,7 +103,7 @@ Example - Pull artifact files from an OCI layout archive 'layout.tar':
 	cmd.Flags().StringVarP(&opts.ManifestConfigRef, "config", "", "", "output manifest config file")
 	cmd.Flags().IntVarP(&opts.concurrency, "concurrency", "", 3, "concurrency level")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return oerrors.Handle(cmd, opts.Target.Recommend)
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func runPull(ctx context.Context, opts *pullOptions) error {

From 0925a45625cda2fde1f3967199ec8b7c3544e6ba Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 29 Dec 2023 09:09:01 +0000
Subject: [PATCH 04/42] support `oras ls` and `oras pull`

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go |  8 +---
 cmd/oras/internal/option/remote.go | 35 ++++++++++++++++-
 cmd/oras/internal/option/target.go | 62 +++++++++++++-----------------
 cmd/oras/root/login.go             |  2 +-
 cmd/oras/root/repo/ls.go           |  2 +-
 5 files changed, 64 insertions(+), 45 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index ceb28d0fa..fe0f2164d 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -72,8 +72,7 @@ type Handler interface {
 
 // Processor processes error.
 type Processor interface {
-	Process(error) error
-	Recommend(err error, callPath string) string
+	Process(err error, callPath string) *Error
 }
 
 // Command returns an error-handled for cobra command.
@@ -88,10 +87,7 @@ func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
 		if processor == nil {
 			return err
 		}
-		return &Error{
-			Err:            processor.Process(err),
-			Recommendation: processor.Recommend(err, cmd.CommandPath()),
-		}
+		return processor.Process(err, cmd.CommandPath())
 	}
 	return cmd
 }
diff --git a/cmd/oras/internal/option/remote.go b/cmd/oras/internal/option/remote.go
index 5547569e5..e3a02f647 100644
--- a/cmd/oras/internal/option/remote.go
+++ b/cmd/oras/internal/option/remote.go
@@ -30,11 +30,14 @@ import (
 
 	credentials "github.com/oras-project/oras-credentials-go"
 	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"oras.land/oras-go/v2/errdef"
 	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras-go/v2/registry/remote/auth"
+	"oras.land/oras-go/v2/registry/remote/errcode"
 	"oras.land/oras-go/v2/registry/remote/retry"
+	oerrors "oras.land/oras/cmd/oras/internal/errors"
 	"oras.land/oras/internal/credential"
 	"oras.land/oras/internal/crypto"
 	onet "oras.land/oras/internal/net"
@@ -42,7 +45,8 @@ import (
 	"oras.land/oras/internal/version"
 )
 
-// Remote options struct.
+// Remote options struct contains flags and arguments specifying one registry.
+// Remote implements oerrors.Handler and oerrors.Processor interface.
 type Remote struct {
 	DistributionSpec
 	CACertFilePath    string
@@ -322,3 +326,32 @@ func (opts *Remote) isPlainHttp(registry string) bool {
 	}
 	return plainHTTP
 }
+
+// Handle handles error during cmd execution.
+func (opts *Remote) Handle(err error, cmd *cobra.Command) (oerrors.Processor, error) {
+	// handle not found error from registry
+	if errors.Is(err, errdef.ErrNotFound) {
+		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
+		return opts, err
+	}
+
+	// handle error response
+	var errResp *errcode.ErrorResponse
+	if errors.As(err, &errResp) {
+		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
+		return opts, errResp
+	}
+	return nil, err
+}
+
+// Process processes error into oerrors.Error.
+func (opts *Remote) Process(err error, _ string) *oerrors.Error {
+	ret := oerrors.Error{
+		Err: err,
+	}
+	if errResp, ok := err.(*errcode.ErrorResponse); ok {
+		// remove HTTP related info
+		ret.Err = errResp.Errors
+	}
+	return &ret
+}
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index cfa5b0bf5..2d66af5b7 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -32,7 +32,6 @@ import (
 	"oras.land/oras-go/v2"
 	"oras.land/oras-go/v2/content"
 	"oras.land/oras-go/v2/content/oci"
-	"oras.land/oras-go/v2/errdef"
 	"oras.land/oras-go/v2/registry"
 	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras-go/v2/registry/remote/errcode"
@@ -47,7 +46,7 @@ const (
 
 // Target struct contains flags and arguments specifying one registry or image
 // layout.
-// Target implements errors.Handler and errors.Processor interface.
+// Target implements oerrors.Handler and oerrors.Processor interface.
 type Target struct {
 	Remote
 	RawReference string
@@ -251,49 +250,40 @@ func (opts *Target) Handle(err error, cmd *cobra.Command) (oerrors.Processor, er
 		return nil, err
 	}
 
-	// handle not found error from registry
-	if errors.Is(err, errdef.ErrNotFound) {
-		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		return opts, err
+	processor, err := opts.Remote.Handle(err, cmd)
+	if processor != nil {
+		processor = opts
 	}
-
-	// handle error response
-	var errResp *errcode.ErrorResponse
-	if errors.As(err, &errResp) {
-		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		return opts, errResp
-	}
-	return opts, err
+	return processor, err
 }
 
-// Process returns a scrubbed error.
-func (opts *Target) Process(err error) error {
-	if errResp, ok := err.(*errcode.ErrorResponse); ok {
-		// remove HTTP related info
-		return errResp.Errors
+// Process processes error into oerrors.Error.
+func (opts *Target) Process(err error, callPath string) *oerrors.Error {
+	ret := oerrors.Error{
+		Err: err,
 	}
-	return err
-}
-
-// Recommend returns a recommendation for known errors.
-func (opts *Target) Recommend(err error, callPath string) string {
 	if opts.IsOCILayout {
-		return ""
-	}
-	ref, parseErr := registry.ParseReference(opts.RawReference)
-	if parseErr != nil {
-		// this should not happen
-		return ""
+		return &ret
 	}
+	if errResp, ok := err.(*errcode.ErrorResponse); ok {
+		// remove HTTP related info
+		ret.Err = errResp.Errors
 
-	if respErr, ok := err.(*errcode.ErrorResponse); ok && ref.Registry == "docker.io" && respErr.URL.Host == ref.Host() && respErr.StatusCode == http.StatusUnauthorized {
-		if !strings.Contains(ref.Repository, "/") {
-			// docker.io/xxx -> docker.io/library/xxx
-			ref.Repository = "library/" + ref.Repository
-			return fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", callPath, ref)
+		ref, parseErr := registry.ParseReference(opts.RawReference)
+		if parseErr != nil {
+			// this should not happen
+			return &ret
+		}
+
+		if ref.Registry == "docker.io" && errResp.URL.Host == ref.Host() && errResp.StatusCode == http.StatusUnauthorized {
+			if !strings.Contains(ref.Repository, "/") {
+				// docker.io/xxx -> docker.io/library/xxx
+				ref.Repository = "library/" + ref.Repository
+				ret.Recommendation = fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", callPath, ref)
+			}
 		}
 	}
-	return ""
+	return &ret
 }
 
 // BinaryTarget struct contains flags and arguments specifying two registries or
diff --git a/cmd/oras/root/login.go b/cmd/oras/root/login.go
index 4eca66986..07e3f43e0 100644
--- a/cmd/oras/root/login.go
+++ b/cmd/oras/root/login.go
@@ -73,7 +73,7 @@ Example - Log in with username and password in an interactive terminal and no TL
 		},
 	}
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Remote)
 }
 
 func runLogin(ctx context.Context, opts loginOptions) (err error) {
diff --git a/cmd/oras/root/repo/ls.go b/cmd/oras/root/repo/ls.go
index ea64b1968..84ffe2e06 100644
--- a/cmd/oras/root/repo/ls.go
+++ b/cmd/oras/root/repo/ls.go
@@ -68,7 +68,7 @@ Example - List the repositories under the registry that include values lexically
 
 	cmd.Flags().StringVar(&opts.last, "last", "", "start after the repository specified by `last`")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Remote)
 }
 
 func listRepository(ctx context.Context, opts repositoryOptions) error {

From 11cb9cfa722ac952c0c63fceed1a831dc0d1c84d Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 29 Dec 2023 09:24:29 +0000
Subject: [PATCH 05/42] add e2e test

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/auth/auth.go    | 8 ++++++++
 test/e2e/suite/command/repo.go | 5 +++++
 2 files changed, 13 insertions(+)

diff --git a/test/e2e/suite/auth/auth.go b/test/e2e/suite/auth/auth.go
index ada87713f..8ef13e1a8 100644
--- a/test/e2e/suite/auth/auth.go
+++ b/test/e2e/suite/auth/auth.go
@@ -90,6 +90,14 @@ var _ = Describe("Common registry user", func() {
 				WithInput(strings.NewReader(fmt.Sprintf("%s\n\n", Username))).ExpectFailure().Exec()
 		})
 
+		It("should fail if password is wrong with registry error prefix", func() {
+			ORAS("login", ZOTHost, "--registry-config", filepath.Join(GinkgoT().TempDir(), tmpConfigName)).
+				WithTimeOut(20*time.Second).
+				MatchKeyWords("Username: ", "Password: ").
+				MatchErrKeyWords("Error response from registry: ").
+				WithInput(strings.NewReader(fmt.Sprintf("%s\n???\n", Username))).ExpectFailure().Exec()
+		})
+
 		It("should fail if no token input", func() {
 			ORAS("login", ZOTHost, "--registry-config", filepath.Join(GinkgoT().TempDir(), tmpConfigName)).
 				WithTimeOut(20*time.Second).
diff --git a/test/e2e/suite/command/repo.go b/test/e2e/suite/command/repo.go
index 0aab9b2bc..ea263f9ff 100644
--- a/test/e2e/suite/command/repo.go
+++ b/test/e2e/suite/command/repo.go
@@ -52,6 +52,11 @@ var _ = Describe("ORAS beginners:", func() {
 				gomega.Expect(err).Should(gbytes.Say("\n"))
 				gomega.Expect(err).Should(gbytes.Say(`Run "oras repo ls -h"`))
 			})
+
+			It("should fail if password is wrong with registry error prefix", func() {
+				ORAS("repo", "ls", ZOTHost, "-u", Username, "-p", "???").
+					MatchErrKeyWords("Error response from registry: ").ExpectFailure().Exec()
+			})
 		})
 		When("running `repo tags`", func() {
 			It("should show help description with feature flags", func() {

From dbdaa590efb264f252de02a119a8fd2cd4eff57b Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 29 Dec 2023 09:25:33 +0000
Subject: [PATCH 06/42] code clean

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index fe0f2164d..b9d743508 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -75,7 +75,7 @@ type Processor interface {
 	Process(err error, callPath string) *Error
 }
 
-// Command returns an error-handled for cobra command.
+// Command returns an error-handled cobra command.
 func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
 	runE := cmd.RunE
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {

From c19a844d9d8366dae860719154d3222dffda4df1 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 29 Dec 2023 09:41:46 +0000
Subject: [PATCH 07/42] add error test for pull

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/pull.go | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/test/e2e/suite/command/pull.go b/test/e2e/suite/command/pull.go
index c841820a9..e8936838a 100644
--- a/test/e2e/suite/command/pull.go
+++ b/test/e2e/suite/command/pull.go
@@ -74,6 +74,22 @@ var _ = Describe("ORAS beginners:", func() {
 			gomega.Expect(err).Should(gbytes.Say("\n"))
 			gomega.Expect(err).Should(gbytes.Say(`Run "oras pull -h"`))
 		})
+
+		It("should fail if password is wrong with registry error prefix", func() {
+			ORAS("pull", RegistryRef(ZOTHost, ArtifactRepo, empty.Tag), "-u", Username, "-p", "???").
+				MatchErrKeyWords("Error response from registry: ").ExpectFailure().Exec()
+		})
+
+		It("should fail if artifact is not found with registry error prefix", func() {
+			ORAS("pull", RegistryRef(ZOTHost, ArtifactRepo, "i-dont-think-this-tag-exists")).
+				MatchErrKeyWords("Error response from registry: ").ExpectFailure().Exec()
+		})
+
+		It("should fail if artifact is not found from OCI layout", func() {
+			root := PrepareTempOCI(ArtifactRepo)
+			ORAS("pull", Flags.Layout, LayoutRef(root, "i-dont-think-this-tag-exists")).
+				MatchErrKeyWords("Error: ").ExpectFailure().Exec()
+		})
 	})
 })
 

From 354df3e5e0cf3064b8bd24542f1adb3651ace2f7 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Tue, 2 Jan 2024 03:00:47 +0000
Subject: [PATCH 08/42] add unit test

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target.go      |   2 +-
 cmd/oras/internal/option/target_test.go | 117 ++++++++++++++++++++++++
 2 files changed, 118 insertions(+), 1 deletion(-)

diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index 2d66af5b7..9677ed5c6 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -276,7 +276,7 @@ func (opts *Target) Process(err error, callPath string) *oerrors.Error {
 		}
 
 		if ref.Registry == "docker.io" && errResp.URL.Host == ref.Host() && errResp.StatusCode == http.StatusUnauthorized {
-			if !strings.Contains(ref.Repository, "/") {
+			if ref.Repository != "" && !strings.Contains(ref.Repository, "/") {
 				// docker.io/xxx -> docker.io/library/xxx
 				ref.Repository = "library/" + ref.Repository
 				ret.Recommendation = fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", callPath, ref)
diff --git a/cmd/oras/internal/option/target_test.go b/cmd/oras/internal/option/target_test.go
index fd13221ae..f8271c64e 100644
--- a/cmd/oras/internal/option/target_test.go
+++ b/cmd/oras/internal/option/target_test.go
@@ -16,7 +16,14 @@ limitations under the License.
 package option
 
 import (
+	"errors"
+	"net/http"
+	"net/url"
+	"reflect"
 	"testing"
+
+	"oras.land/oras-go/v2/registry/remote/errcode"
+	oerrors "oras.land/oras/cmd/oras/internal/errors"
 )
 
 func TestTarget_Parse_oci(t *testing.T) {
@@ -75,3 +82,113 @@ func Test_parseOCILayoutReference(t *testing.T) {
 		})
 	}
 }
+
+func TestTarget_Process_ociLayout(t *testing.T) {
+	errClient := errors.New("client error")
+	opts := &Target{
+		IsOCILayout: true,
+	}
+	if got := opts.Process(errClient, ""); got.Err != errClient || got.Recommendation != "" {
+		t.Errorf("unexpected output from Target.Process() = %v", got)
+	}
+}
+
+func TestTarget_Process_hint(t *testing.T) {
+	type fields struct {
+		Remote       Remote
+		RawReference string
+		Type         string
+		Reference    string
+		Path         string
+		IsOCILayout  bool
+	}
+	type args struct {
+		err      error
+		callPath string
+	}
+	errs := errcode.Errors{
+		errcode.Error{
+			Code:    "000",
+			Message: "mocked message",
+			Detail:  map[string]string{"mocked key": "mocked value"},
+		},
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   *oerrors.Error
+	}{
+		{
+			"namespace already exists",
+			fields{RawReference: "docker.io/library/alpine:latest"},
+			args{
+				err: &errcode.ErrorResponse{
+					URL:        &url.URL{Host: "registry-1.docker.io"},
+					StatusCode: http.StatusUnauthorized,
+					Errors:     errs,
+				},
+			},
+			&oerrors.Error{Err: errs},
+		},
+		{
+			"no namespace",
+			fields{RawReference: "docker.io"},
+			args{
+				err: &errcode.ErrorResponse{
+					URL:        &url.URL{Host: "registry-1.docker.io"},
+					StatusCode: http.StatusUnauthorized,
+					Errors:     errs,
+				},
+			},
+			&oerrors.Error{Err: errs},
+		},
+		{
+			"not 401",
+			fields{RawReference: "docker.io"},
+			args{
+				err: &errcode.ErrorResponse{
+					URL:        &url.URL{Host: "registry-1.docker.io"},
+					StatusCode: http.StatusConflict,
+					Errors:     errs,
+				},
+			},
+			&oerrors.Error{Err: errs},
+		},
+		{
+			"should hint",
+			fields{
+				RawReference: "docker.io/alpine",
+				Path:         "oras test",
+			},
+			args{
+				err: &errcode.ErrorResponse{
+					URL:        &url.URL{Host: "registry-1.docker.io"},
+					StatusCode: http.StatusUnauthorized,
+					Errors:     errs,
+				},
+				callPath: "oras test",
+			},
+			&oerrors.Error{
+				Err:            errs,
+				Recommendation: "Namespace is missing, do you mean `oras test docker.io/library/alpine`?",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			opts := &Target{
+				Remote:       tt.fields.Remote,
+				RawReference: tt.fields.RawReference,
+				Type:         tt.fields.Type,
+				Reference:    tt.fields.Reference,
+				Path:         tt.fields.Path,
+				IsOCILayout:  tt.fields.IsOCILayout,
+			}
+			got := opts.Process(tt.args.err, tt.args.callPath)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Target.Process() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

From 20e23e3c9d20c05455539a341b86b41551967531 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Tue, 2 Jan 2024 07:04:05 +0000
Subject: [PATCH 09/42] support error prefix in cp and resolve

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target.go            |  6 +++-
 cmd/oras/root/cp.go                           |  2 +-
 cmd/oras/root/resolve.go                      |  2 +-
 .../e2e/internal/utils/{flags.go => const.go} | 30 +++++++++++--------
 test/e2e/suite/auth/auth.go                   |  2 +-
 test/e2e/suite/command/cp.go                  | 15 +++++++++-
 test/e2e/suite/command/pull.go                |  8 ++---
 test/e2e/suite/command/repo.go                |  2 +-
 test/e2e/suite/command/resolve.go             |  2 +-
 test/e2e/suite/command/tag.go                 |  2 +-
 10 files changed, 46 insertions(+), 25 deletions(-)
 rename test/e2e/internal/utils/{flags.go => const.go} (60%)

diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index 9677ed5c6..d3e6a2f71 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -321,7 +321,11 @@ func (opts *BinaryTarget) Parse() error {
 // Handle handles error during cmd execution.
 func (opts *BinaryTarget) Handle(err error, cmd *cobra.Command) (oerrors.Processor, error) {
 	if processor, err := opts.From.Handle(err, cmd); processor != nil {
-		return processor, err
+		if errResp, ok := err.(*errcode.ErrorResponse); ok {
+			if ref, _ := registry.ParseReference(opts.From.RawReference); errResp.URL.Host == ref.Host() {
+				return processor, err
+			}
+		}
 	}
 	return opts.To.Handle(err, cmd)
 }
diff --git a/cmd/oras/root/cp.go b/cmd/oras/root/cp.go
index 28d61f275..94eb52044 100644
--- a/cmd/oras/root/cp.go
+++ b/cmd/oras/root/cp.go
@@ -102,7 +102,7 @@ Example - Copy an artifact with multiple tags with concurrency tuned:
 	cmd.Flags().IntVarP(&opts.concurrency, "concurrency", "", 3, "concurrency level")
 	opts.EnableDistributionSpecFlag()
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.BinaryTarget)
 }
 
 func runCopy(ctx context.Context, opts copyOptions) error {
diff --git a/cmd/oras/root/resolve.go b/cmd/oras/root/resolve.go
index 976fac3cc..c1d533d34 100644
--- a/cmd/oras/root/resolve.go
+++ b/cmd/oras/root/resolve.go
@@ -58,7 +58,7 @@ Example - Resolve digest of the target artifact:
 
 	cmd.Flags().BoolVarP(&opts.fullRef, "full-reference", "l", false, "print the full artifact reference with digest")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func runResolve(ctx context.Context, opts resolveOptions) error {
diff --git a/test/e2e/internal/utils/flags.go b/test/e2e/internal/utils/const.go
similarity index 60%
rename from test/e2e/internal/utils/flags.go
rename to test/e2e/internal/utils/const.go
index 893fa575d..63b0fadea 100644
--- a/test/e2e/internal/utils/flags.go
+++ b/test/e2e/internal/utils/const.go
@@ -15,16 +15,20 @@ limitations under the License.
 
 package utils
 
-var Flags = struct {
-	Layout           string
-	FromLayout       string
-	ToLayout         string
-	DistributionSpec string
-	ImageSpec        string
-}{
-	"--oci-layout",
-	"--from-oci-layout",
-	"--to-oci-layout",
-	"--distribution-spec",
-	"--image-spec",
-}
+var (
+	Flags = struct {
+		Layout           string
+		FromLayout       string
+		ToLayout         string
+		DistributionSpec string
+		ImageSpec        string
+	}{
+		"--oci-layout",
+		"--from-oci-layout",
+		"--to-oci-layout",
+		"--distribution-spec",
+		"--image-spec",
+	}
+	RegistryErrorPrefix = "Error response from registry: "
+	InvalidTag          = "i-dont-think-this-tag-exists"
+)
diff --git a/test/e2e/suite/auth/auth.go b/test/e2e/suite/auth/auth.go
index 8ef13e1a8..9c0988c2a 100644
--- a/test/e2e/suite/auth/auth.go
+++ b/test/e2e/suite/auth/auth.go
@@ -94,7 +94,7 @@ var _ = Describe("Common registry user", func() {
 			ORAS("login", ZOTHost, "--registry-config", filepath.Join(GinkgoT().TempDir(), tmpConfigName)).
 				WithTimeOut(20*time.Second).
 				MatchKeyWords("Username: ", "Password: ").
-				MatchErrKeyWords("Error response from registry: ").
+				MatchErrKeyWords(RegistryErrorPrefix).
 				WithInput(strings.NewReader(fmt.Sprintf("%s\n???\n", Username))).ExpectFailure().Exec()
 		})
 
diff --git a/test/e2e/suite/command/cp.go b/test/e2e/suite/command/cp.go
index 45718fa29..85420360c 100644
--- a/test/e2e/suite/command/cp.go
+++ b/test/e2e/suite/command/cp.go
@@ -57,7 +57,7 @@ var _ = Describe("ORAS beginners:", func() {
 		})
 
 		It("should fail when source doesn't exist", func() {
-			ORAS("cp", RegistryRef(ZOTHost, ImageRepo, "i-dont-think-this-tag-exists"), RegistryRef(ZOTHost, cpTestRepo("nonexistent-source"), "")).ExpectFailure().MatchErrKeyWords("Error:").Exec()
+			ORAS("cp", RegistryRef(ZOTHost, ImageRepo, InvalidTag), RegistryRef(ZOTHost, cpTestRepo("nonexistent-source"), "")).ExpectFailure().MatchErrKeyWords("Error:").Exec()
 		})
 
 		It("should fail and show detailed error description if no argument provided", func() {
@@ -75,6 +75,19 @@ var _ = Describe("ORAS beginners:", func() {
 			Expect(err).Should(gbytes.Say("\n"))
 			Expect(err).Should(gbytes.Say(`Run "oras cp -h"`))
 		})
+
+		It("should fail and show registry error prefix if source not found", func() {
+			src := RegistryRef(ZOTHost, ArtifactRepo, InvalidTag)
+			dst := GinkgoT().TempDir()
+			ORAS("cp", src, Flags.ToLayout, dst).MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
+		})
+
+		It("should fail and show registry error prefix if target registry is not logged in", Focus, func() {
+			src := RegistryRef(ZOTHost, ArtifactRepo, foobar.Tag)
+			dst := RegistryRef(ZOTHost, cpTestRepo("dest-not-logged-in"), "")
+			ORAS("cp", src, dst, "--to-username", Username, "--to-password", Password+"?").
+				MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
+		})
 	})
 })
 
diff --git a/test/e2e/suite/command/pull.go b/test/e2e/suite/command/pull.go
index e8936838a..ebd5cf61b 100644
--- a/test/e2e/suite/command/pull.go
+++ b/test/e2e/suite/command/pull.go
@@ -77,17 +77,17 @@ var _ = Describe("ORAS beginners:", func() {
 
 		It("should fail if password is wrong with registry error prefix", func() {
 			ORAS("pull", RegistryRef(ZOTHost, ArtifactRepo, empty.Tag), "-u", Username, "-p", "???").
-				MatchErrKeyWords("Error response from registry: ").ExpectFailure().Exec()
+				MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
 		})
 
 		It("should fail if artifact is not found with registry error prefix", func() {
-			ORAS("pull", RegistryRef(ZOTHost, ArtifactRepo, "i-dont-think-this-tag-exists")).
-				MatchErrKeyWords("Error response from registry: ").ExpectFailure().Exec()
+			ORAS("pull", RegistryRef(ZOTHost, ArtifactRepo, InvalidTag)).
+				MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
 		})
 
 		It("should fail if artifact is not found from OCI layout", func() {
 			root := PrepareTempOCI(ArtifactRepo)
-			ORAS("pull", Flags.Layout, LayoutRef(root, "i-dont-think-this-tag-exists")).
+			ORAS("pull", Flags.Layout, LayoutRef(root, InvalidTag)).
 				MatchErrKeyWords("Error: ").ExpectFailure().Exec()
 		})
 	})
diff --git a/test/e2e/suite/command/repo.go b/test/e2e/suite/command/repo.go
index ea263f9ff..525884ca3 100644
--- a/test/e2e/suite/command/repo.go
+++ b/test/e2e/suite/command/repo.go
@@ -55,7 +55,7 @@ var _ = Describe("ORAS beginners:", func() {
 
 			It("should fail if password is wrong with registry error prefix", func() {
 				ORAS("repo", "ls", ZOTHost, "-u", Username, "-p", "???").
-					MatchErrKeyWords("Error response from registry: ").ExpectFailure().Exec()
+					MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
 			})
 		})
 		When("running `repo tags`", func() {
diff --git a/test/e2e/suite/command/resolve.go b/test/e2e/suite/command/resolve.go
index fac8266b4..1344cf48f 100644
--- a/test/e2e/suite/command/resolve.go
+++ b/test/e2e/suite/command/resolve.go
@@ -47,7 +47,7 @@ var _ = Describe("ORAS beginners:", func() {
 			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, "")).ExpectFailure().MatchErrKeyWords("Error:", "no tag or digest when expecting <name:tag|name@digest>").Exec()
 		})
 		It("should fail when provided manifest reference is not found", func() {
-			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, "i-dont-think-this-tag-exists")).ExpectFailure().MatchErrKeyWords("Error: failed to resolve digest:", "not found").Exec()
+			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, InvalidTag)).ExpectFailure().MatchErrKeyWords("Error: failed to resolve digest:", "not found").Exec()
 		})
 
 		It("should fail and show detailed error description if no argument provided", func() {
diff --git a/test/e2e/suite/command/tag.go b/test/e2e/suite/command/tag.go
index 3c98dcea3..2fd556b9e 100644
--- a/test/e2e/suite/command/tag.go
+++ b/test/e2e/suite/command/tag.go
@@ -33,7 +33,7 @@ var _ = Describe("ORAS beginners:", func() {
 		})
 
 		It("should fail when provided manifest reference is not found", func() {
-			ORAS("tag", RegistryRef(ZOTHost, ImageRepo, "i-dont-think-this-tag-exists"), "tagged").ExpectFailure().MatchErrKeyWords("Error:").Exec()
+			ORAS("tag", RegistryRef(ZOTHost, ImageRepo, InvalidTag), "tagged").ExpectFailure().MatchErrKeyWords("Error:").Exec()
 		})
 
 		It("should fail and show detailed error description if no argument provided", func() {

From 859441182626409fc2bb88594e32494e1b74ca2b Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Tue, 2 Jan 2024 07:05:17 +0000
Subject: [PATCH 10/42] support push

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/root/push.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/oras/root/push.go b/cmd/oras/root/push.go
index 0ee581a5f..c4825de09 100644
--- a/cmd/oras/root/push.go
+++ b/cmd/oras/root/push.go
@@ -132,7 +132,7 @@ Example - Push file "hi.txt" into an OCI image layout folder 'layout-dir' with t
 	cmd.Flags().IntVarP(&opts.concurrency, "concurrency", "", 5, "concurrency level")
 
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func runPush(ctx context.Context, opts pushOptions) error {

From 6d0a53341e90f980850b51fba895444dc0292246 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 5 Jan 2024 09:04:44 +0000
Subject: [PATCH 11/42] fix e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/cp.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/e2e/suite/command/cp.go b/test/e2e/suite/command/cp.go
index 85420360c..4640281b0 100644
--- a/test/e2e/suite/command/cp.go
+++ b/test/e2e/suite/command/cp.go
@@ -82,7 +82,7 @@ var _ = Describe("ORAS beginners:", func() {
 			ORAS("cp", src, Flags.ToLayout, dst).MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
 		})
 
-		It("should fail and show registry error prefix if target registry is not logged in", Focus, func() {
+		It("should fail and show registry error prefix if target registry is not logged in", func() {
 			src := RegistryRef(ZOTHost, ArtifactRepo, foobar.Tag)
 			dst := RegistryRef(ZOTHost, cpTestRepo("dest-not-logged-in"), "")
 			ORAS("cp", src, dst, "--to-username", Username, "--to-password", Password+"?").

From 317556b47df853bdbec4c0e964e362329c2c0672 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 5 Jan 2024 11:46:20 +0000
Subject: [PATCH 12/42] scrub debug info & handle empty response body

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 19 +++++++++++++++++++
 cmd/oras/internal/option/remote.go | 10 ++++++----
 cmd/oras/internal/option/target.go |  4 +++-
 3 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index b9d743508..cc9b566ce 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -17,9 +17,11 @@ package errors
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/spf13/cobra"
 	"oras.land/oras-go/v2/registry"
+	"oras.land/oras-go/v2/registry/remote/errcode"
 )
 
 // RegistryErrorPrefix is the commandline prefix for errors from registry.
@@ -92,6 +94,23 @@ func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
 	return cmd
 }
 
+// GetInnerError gets the inner error from the error response.
+// nil is returned if no valid inner error is found.
+func GetInnerError(err error, errResp *errcode.ErrorResponse) error {
+	inner := errResp.Errors
+	if len(inner) == 0 {
+		return fmt.Errorf("empty response body: %w", errResp)
+	} else {
+		errContent := err.Error()
+		errRespContent := errResp.Error()
+		if idx := strings.Index(errContent, errRespContent); idx > 0 {
+			// remove HTTP related info
+			return fmt.Errorf("%s: %w", errContent[:idx], errResp)
+		}
+	}
+	return nil
+}
+
 // NewErrEmptyTagOrDigest creates a new error based on the reference string.
 func NewErrEmptyTagOrDigest(ref registry.Reference) error {
 	return NewErrEmptyTagOrDigestStr(ref.String())
diff --git a/cmd/oras/internal/option/remote.go b/cmd/oras/internal/option/remote.go
index e3a02f647..3814b0106 100644
--- a/cmd/oras/internal/option/remote.go
+++ b/cmd/oras/internal/option/remote.go
@@ -339,7 +339,7 @@ func (opts *Remote) Handle(err error, cmd *cobra.Command) (oerrors.Processor, er
 	var errResp *errcode.ErrorResponse
 	if errors.As(err, &errResp) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		return opts, errResp
+		return opts, err
 	}
 	return nil, err
 }
@@ -349,9 +349,11 @@ func (opts *Remote) Process(err error, _ string) *oerrors.Error {
 	ret := oerrors.Error{
 		Err: err,
 	}
-	if errResp, ok := err.(*errcode.ErrorResponse); ok {
-		// remove HTTP related info
-		ret.Err = errResp.Errors
+	var errResp *errcode.ErrorResponse
+	if errors.As(err, &errResp) {
+		if innerErr := oerrors.GetInnerError(err, errResp); innerErr != nil {
+			ret.Err = innerErr
+		}
 	}
 	return &ret
 }
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index d3e6a2f71..7908c064a 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -267,7 +267,9 @@ func (opts *Target) Process(err error, callPath string) *oerrors.Error {
 	}
 	if errResp, ok := err.(*errcode.ErrorResponse); ok {
 		// remove HTTP related info
-		ret.Err = errResp.Errors
+		if innerErr := oerrors.GetInnerError(err, errResp); innerErr != nil {
+			ret.Err = innerErr
+		}
 
 		ref, parseErr := registry.ParseReference(opts.RawReference)
 		if parseErr != nil {

From 40766353f2f42e386e16aeb6c2f5bb69440d370f Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 5 Jan 2024 12:53:40 +0000
Subject: [PATCH 13/42] fix e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/cp.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/e2e/suite/command/cp.go b/test/e2e/suite/command/cp.go
index 4640281b0..ba09d4bef 100644
--- a/test/e2e/suite/command/cp.go
+++ b/test/e2e/suite/command/cp.go
@@ -57,7 +57,7 @@ var _ = Describe("ORAS beginners:", func() {
 		})
 
 		It("should fail when source doesn't exist", func() {
-			ORAS("cp", RegistryRef(ZOTHost, ImageRepo, InvalidTag), RegistryRef(ZOTHost, cpTestRepo("nonexistent-source"), "")).ExpectFailure().MatchErrKeyWords("Error:").Exec()
+			ORAS("cp", RegistryRef(ZOTHost, ImageRepo, InvalidTag), RegistryRef(ZOTHost, cpTestRepo("nonexistent-source"), "")).ExpectFailure().MatchErrKeyWords(InvalidTag).Exec()
 		})
 
 		It("should fail and show detailed error description if no argument provided", func() {

From 1d3fefa213bbb2158adda5fdbf1915468baebd58 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Fri, 5 Jan 2024 13:23:18 +0000
Subject: [PATCH 14/42] fix e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/resolve.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/e2e/suite/command/resolve.go b/test/e2e/suite/command/resolve.go
index 1344cf48f..aa6e009db 100644
--- a/test/e2e/suite/command/resolve.go
+++ b/test/e2e/suite/command/resolve.go
@@ -47,7 +47,7 @@ var _ = Describe("ORAS beginners:", func() {
 			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, "")).ExpectFailure().MatchErrKeyWords("Error:", "no tag or digest when expecting <name:tag|name@digest>").Exec()
 		})
 		It("should fail when provided manifest reference is not found", func() {
-			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, InvalidTag)).ExpectFailure().MatchErrKeyWords("Error: failed to resolve digest:", "not found").Exec()
+			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, InvalidTag)).ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix, "failed to resolve digest:", "not found").Exec()
 		})
 
 		It("should fail and show detailed error description if no argument provided", func() {

From 1c01b0aa2dc6c259c96d83ebe34cbf56d596e9eb Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Sun, 7 Jan 2024 09:47:27 +0000
Subject: [PATCH 15/42] fix e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target.go | 4 +++-
 test/e2e/internal/utils/const.go   | 1 +
 test/e2e/suite/command/resolve.go  | 8 +++++++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index 7908c064a..f39866ef9 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -265,7 +265,9 @@ func (opts *Target) Process(err error, callPath string) *oerrors.Error {
 	if opts.IsOCILayout {
 		return &ret
 	}
-	if errResp, ok := err.(*errcode.ErrorResponse); ok {
+
+	var errResp *errcode.ErrorResponse
+	if errors.As(err, &errResp) {
 		// remove HTTP related info
 		if innerErr := oerrors.GetInnerError(err, errResp); innerErr != nil {
 			ret.Err = innerErr
diff --git a/test/e2e/internal/utils/const.go b/test/e2e/internal/utils/const.go
index 63b0fadea..f13d3a4de 100644
--- a/test/e2e/internal/utils/const.go
+++ b/test/e2e/internal/utils/const.go
@@ -30,5 +30,6 @@ var (
 		"--image-spec",
 	}
 	RegistryErrorPrefix = "Error response from registry: "
+	EmptyBodyPrefix     = "empty response body: "
 	InvalidTag          = "i-dont-think-this-tag-exists"
 )
diff --git a/test/e2e/suite/command/resolve.go b/test/e2e/suite/command/resolve.go
index aa6e009db..52f85c64d 100644
--- a/test/e2e/suite/command/resolve.go
+++ b/test/e2e/suite/command/resolve.go
@@ -47,7 +47,13 @@ var _ = Describe("ORAS beginners:", func() {
 			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, "")).ExpectFailure().MatchErrKeyWords("Error:", "no tag or digest when expecting <name:tag|name@digest>").Exec()
 		})
 		It("should fail when provided manifest reference is not found", func() {
-			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, InvalidTag)).ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix, "failed to resolve digest:", "not found").Exec()
+			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, "i-dont-think-this-tag-exists")).ExpectFailure().MatchErrKeyWords("Error: failed to resolve digest:", "not found").Exec()
+		})
+		It("should fail with empty response when returned response doesn't have body", func() {
+			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, InvalidTag), "-u", Username, "-p", Password+"1").
+				ExpectFailure().
+				MatchErrKeyWords(RegistryErrorPrefix, EmptyBodyPrefix, "response status code 401: Unauthorized").
+				Exec()
 		})
 
 		It("should fail and show detailed error description if no argument provided", func() {

From 937d80c5e10e38e3b78fff0ac633fa1fff9a0c4a Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Sun, 7 Jan 2024 10:36:03 +0000
Subject: [PATCH 16/42] fix e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/resolve.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/e2e/suite/command/resolve.go b/test/e2e/suite/command/resolve.go
index 52f85c64d..9a345f11e 100644
--- a/test/e2e/suite/command/resolve.go
+++ b/test/e2e/suite/command/resolve.go
@@ -47,7 +47,7 @@ var _ = Describe("ORAS beginners:", func() {
 			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, "")).ExpectFailure().MatchErrKeyWords("Error:", "no tag or digest when expecting <name:tag|name@digest>").Exec()
 		})
 		It("should fail when provided manifest reference is not found", func() {
-			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, "i-dont-think-this-tag-exists")).ExpectFailure().MatchErrKeyWords("Error: failed to resolve digest:", "not found").Exec()
+			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, "i-dont-think-this-tag-exists")).ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix, "failed to resolve digest:", "not found").Exec()
 		})
 		It("should fail with empty response when returned response doesn't have body", func() {
 			ORAS("resolve", RegistryRef(ZOTHost, ImageRepo, InvalidTag), "-u", Username, "-p", Password+"1").

From ae3dd7b8ba087da9178a682f25df049663914f8a Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 8 Jan 2024 02:08:21 +0000
Subject: [PATCH 17/42] support all commands and add e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/root/attach.go                |  2 +-
 cmd/oras/root/blob/delete.go           |  2 +-
 cmd/oras/root/blob/fetch.go            |  2 +-
 cmd/oras/root/blob/push.go             |  2 +-
 cmd/oras/root/discover.go              |  2 +-
 cmd/oras/root/manifest/delete.go       |  2 +-
 cmd/oras/root/manifest/fetch.go        |  2 +-
 cmd/oras/root/manifest/fetch_config.go |  2 +-
 cmd/oras/root/manifest/push.go         |  2 +-
 cmd/oras/root/repo/tags.go             |  2 +-
 cmd/oras/root/tag.go                   |  2 +-
 test/e2e/suite/auth/auth.go            | 23 +++++++++++++++++++++++
 12 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/cmd/oras/root/attach.go b/cmd/oras/root/attach.go
index 528a01b47..f16d0fc4d 100644
--- a/cmd/oras/root/attach.go
+++ b/cmd/oras/root/attach.go
@@ -96,7 +96,7 @@ Example - Attach file to the manifest tagged 'v1' in an OCI image layout folder
 	_ = cmd.MarkFlagRequired("artifact-type")
 	opts.EnableDistributionSpecFlag()
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func runAttach(ctx context.Context, opts attachOptions) error {
diff --git a/cmd/oras/root/blob/delete.go b/cmd/oras/root/blob/delete.go
index fe22a1389..866aaf40f 100644
--- a/cmd/oras/root/blob/delete.go
+++ b/cmd/oras/root/blob/delete.go
@@ -69,7 +69,7 @@ Example - Delete a blob and print its descriptor:
 	}
 
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func deleteBlob(ctx context.Context, opts deleteBlobOptions) (err error) {
diff --git a/cmd/oras/root/blob/fetch.go b/cmd/oras/root/blob/fetch.go
index 3ebb4187f..fdfdb7abc 100644
--- a/cmd/oras/root/blob/fetch.go
+++ b/cmd/oras/root/blob/fetch.go
@@ -89,7 +89,7 @@ Example - Fetch and print a blob from OCI image layout archive file 'layout.tar'
 
 	cmd.Flags().StringVarP(&opts.outputPath, "output", "o", "", "output file `path`, use - for stdout")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func fetchBlob(ctx context.Context, opts fetchBlobOptions) (fetchErr error) {
diff --git a/cmd/oras/root/blob/push.go b/cmd/oras/root/blob/push.go
index 801874048..1f892a6c2 100644
--- a/cmd/oras/root/blob/push.go
+++ b/cmd/oras/root/blob/push.go
@@ -97,7 +97,7 @@ Example - Push blob 'hi.txt' into an OCI image layout folder 'layout-dir':
 	cmd.Flags().Int64VarP(&opts.size, "size", "", -1, "provide the blob size")
 	cmd.Flags().StringVarP(&opts.mediaType, "media-type", "", ocispec.MediaTypeImageLayer, "specify the returned media type in the descriptor if --descriptor is used")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func pushBlob(ctx context.Context, opts pushBlobOptions) (err error) {
diff --git a/cmd/oras/root/discover.go b/cmd/oras/root/discover.go
index 6b98d4a22..a35db60a2 100644
--- a/cmd/oras/root/discover.go
+++ b/cmd/oras/root/discover.go
@@ -89,7 +89,7 @@ Example - Discover referrers of the manifest tagged 'v1' in an OCI image layout
 	cmd.Flags().StringVarP(&opts.outputType, "output", "o", "table", "format in which to display referrers (table, json, or tree). tree format will also show indirect referrers")
 	opts.EnableDistributionSpecFlag()
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func runDiscover(ctx context.Context, opts discoverOptions) error {
diff --git a/cmd/oras/root/manifest/delete.go b/cmd/oras/root/manifest/delete.go
index b8e43f0c6..fa4cf75fe 100644
--- a/cmd/oras/root/manifest/delete.go
+++ b/cmd/oras/root/manifest/delete.go
@@ -73,7 +73,7 @@ Example - Delete a manifest by digest 'sha256:99e4703fbf30916f549cd6bfa9cdbab614
 
 	opts.EnableDistributionSpecFlag()
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func deleteManifest(ctx context.Context, opts deleteOptions) error {
diff --git a/cmd/oras/root/manifest/fetch.go b/cmd/oras/root/manifest/fetch.go
index dad6917c1..4862891b8 100644
--- a/cmd/oras/root/manifest/fetch.go
+++ b/cmd/oras/root/manifest/fetch.go
@@ -88,7 +88,7 @@ Example - Fetch raw manifest from an OCI layout archive file 'layout.tar':
 	cmd.Flags().StringSliceVarP(&opts.mediaTypes, "media-type", "", nil, "accepted media types")
 	cmd.Flags().StringVarP(&opts.outputPath, "output", "o", "", "file `path` to write the fetched manifest to, use - for stdout")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func fetchManifest(ctx context.Context, opts fetchOptions) (fetchErr error) {
diff --git a/cmd/oras/root/manifest/fetch_config.go b/cmd/oras/root/manifest/fetch_config.go
index 2ce4a8e6b..2519e491b 100644
--- a/cmd/oras/root/manifest/fetch_config.go
+++ b/cmd/oras/root/manifest/fetch_config.go
@@ -84,7 +84,7 @@ Example - Fetch and print the prettified descriptor of the config:
 
 	cmd.Flags().StringVarP(&opts.outputPath, "output", "o", "", "file `path` to write the fetched config to, use - for stdout")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func fetchConfig(ctx context.Context, opts fetchConfigOptions) (fetchErr error) {
diff --git a/cmd/oras/root/manifest/push.go b/cmd/oras/root/manifest/push.go
index d001ffd2f..2043b3625 100644
--- a/cmd/oras/root/manifest/push.go
+++ b/cmd/oras/root/manifest/push.go
@@ -102,7 +102,7 @@ Example - Push a manifest to an OCI image layout folder 'layout-dir' and tag wit
 	option.ApplyFlags(&opts, cmd.Flags())
 	cmd.Flags().StringVarP(&opts.mediaType, "media-type", "", "", "media type of manifest")
 	cmd.Flags().IntVarP(&opts.concurrency, "concurrency", "", 5, "concurrency level")
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func pushManifest(ctx context.Context, opts pushOptions) error {
diff --git a/cmd/oras/root/repo/tags.go b/cmd/oras/root/repo/tags.go
index 6eddc504b..eacb87594 100644
--- a/cmd/oras/root/repo/tags.go
+++ b/cmd/oras/root/repo/tags.go
@@ -76,7 +76,7 @@ Example - [Experimental] Show tags associated with a digest:
 	cmd.Flags().StringVar(&opts.last, "last", "", "start after the tag specified by `last`")
 	cmd.Flags().BoolVar(&opts.excludeDigestTag, "exclude-digest-tags", false, "[Preview] exclude all digest-like tags such as 'sha256-aaaa...'")
 	option.ApplyFlags(&opts, cmd.Flags())
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func showTags(ctx context.Context, opts showTagsOptions) error {
diff --git a/cmd/oras/root/tag.go b/cmd/oras/root/tag.go
index dcc857f1f..51c6d81cb 100644
--- a/cmd/oras/root/tag.go
+++ b/cmd/oras/root/tag.go
@@ -88,7 +88,7 @@ Example - Tag the manifest 'v1.0.1' to 'v1.0.2' in an OCI image layout folder 'l
 
 	option.ApplyFlags(&opts, cmd.Flags())
 	cmd.Flags().IntVarP(&opts.concurrency, "concurrency", "", 5, "concurrency level")
-	return cmd
+	return oerrors.Command(cmd, &opts.Target)
 }
 
 func tagManifest(ctx context.Context, opts tagOptions) error {
diff --git a/test/e2e/suite/auth/auth.go b/test/e2e/suite/auth/auth.go
index 9c0988c2a..5d192dab6 100644
--- a/test/e2e/suite/auth/auth.go
+++ b/test/e2e/suite/auth/auth.go
@@ -49,6 +49,23 @@ var _ = Describe("Common registry user", func() {
 		})
 	})
 
+	When("credential is invalid", func() {
+		It("should fail with registry error", func() {
+			RunWithInvalidCreds("attach", ZOTHost+"/repo:tag", "-a", "test=true", "--artifact-type", "doc/example")
+			RunWithInvalidCreds("discover", ZOTHost+"/repo:tag")
+			RunWithInvalidCreds("push", "-a", "key=value", ZOTHost+"/repo:tag")
+			RunWithInvalidCreds("pull", ZOTHost+"/repo:tag")
+			RunWithInvalidCreds("manifest", "fetch", ZOTHost+"/repo:tag")
+			RunWithInvalidCreds("blob", "delete", ZOTHost+"/repo@sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
+			RunWithInvalidCreds("blob", "push", ZOTHost+"/repo", WriteTempFile("blob", "test"))
+			RunWithInvalidCreds("tag", ZOTHost+"/repo:tag", "tag1")
+			RunWithInvalidCreds("resolve", ZOTHost+"/repo:tag")
+			RunWithInvalidCreds("repo", "ls", ZOTHost)
+			RunWithInvalidCreds("repo", "tags", RegistryRef(ZOTHost, "repo", ""))
+			RunWithInvalidCreds("manifest", "fetch-config", ZOTHost+"/repo:tag")
+		})
+	})
+
 	When("logging in", func() {
 		tmpConfigName := "test.config"
 		It("should succeed to use basic auth", func() {
@@ -137,3 +154,9 @@ func RunWithoutLogin(args ...string) {
 		MatchErrKeyWords("Error:", "credential required").
 		WithDescription("fail without logging in").Exec()
 }
+
+func RunWithInvalidCreds(args ...string) {
+	ORAS(append(args, "-u", Username, "-p", Password+"1")...).ExpectFailure().
+		MatchErrKeyWords(RegistryErrorPrefix).
+		WithDescription("fail with invalid credentials").Exec()
+}

From 70ac3a040be3f617052e3e3606f70c8b52786771 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 8 Jan 2024 02:20:09 +0000
Subject: [PATCH 18/42] bug fix

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index cc9b566ce..1b5ab1a39 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -105,10 +105,10 @@ func GetInnerError(err error, errResp *errcode.ErrorResponse) error {
 		errRespContent := errResp.Error()
 		if idx := strings.Index(errContent, errRespContent); idx > 0 {
 			// remove HTTP related info
-			return fmt.Errorf("%s: %w", errContent[:idx], errResp)
+			return fmt.Errorf("%s: %w", errContent[:idx], inner)
 		}
 	}
-	return nil
+	return inner
 }
 
 // NewErrEmptyTagOrDigest creates a new error based on the reference string.

From 92588f53f3ba5a528198738a2a1df70e0fb71a0b Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 8 Jan 2024 02:54:15 +0000
Subject: [PATCH 19/42] improve readability

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index 1b5ab1a39..f90f2bccd 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -105,7 +105,7 @@ func GetInnerError(err error, errResp *errcode.ErrorResponse) error {
 		errRespContent := errResp.Error()
 		if idx := strings.Index(errContent, errRespContent); idx > 0 {
 			// remove HTTP related info
-			return fmt.Errorf("%s: %w", errContent[:idx], inner)
+			return fmt.Errorf("%s%w", errContent[:idx], inner)
 		}
 	}
 	return inner

From 668152d6751c67e31325bc4d471943040d361479 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 8 Jan 2024 03:04:46 +0000
Subject: [PATCH 20/42] resolve empty resp body

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 4 ++--
 cmd/oras/internal/option/remote.go | 4 +---
 cmd/oras/internal/option/target.go | 4 +---
 3 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index f90f2bccd..e9bfb8947 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -94,9 +94,9 @@ func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
 	return cmd
 }
 
-// GetInnerError gets the inner error from the error response.
+// GetInner gets the inner error from the error response.
 // nil is returned if no valid inner error is found.
-func GetInnerError(err error, errResp *errcode.ErrorResponse) error {
+func GetInner(err error, errResp *errcode.ErrorResponse) error {
 	inner := errResp.Errors
 	if len(inner) == 0 {
 		return fmt.Errorf("empty response body: %w", errResp)
diff --git a/cmd/oras/internal/option/remote.go b/cmd/oras/internal/option/remote.go
index 3814b0106..906ca2835 100644
--- a/cmd/oras/internal/option/remote.go
+++ b/cmd/oras/internal/option/remote.go
@@ -351,9 +351,7 @@ func (opts *Remote) Process(err error, _ string) *oerrors.Error {
 	}
 	var errResp *errcode.ErrorResponse
 	if errors.As(err, &errResp) {
-		if innerErr := oerrors.GetInnerError(err, errResp); innerErr != nil {
-			ret.Err = innerErr
-		}
+		ret.Err = oerrors.GetInner(err, errResp)
 	}
 	return &ret
 }
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index f39866ef9..dafb0df60 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -269,9 +269,7 @@ func (opts *Target) Process(err error, callPath string) *oerrors.Error {
 	var errResp *errcode.ErrorResponse
 	if errors.As(err, &errResp) {
 		// remove HTTP related info
-		if innerErr := oerrors.GetInnerError(err, errResp); innerErr != nil {
-			ret.Err = innerErr
-		}
+		ret.Err = oerrors.GetInner(err, errResp)
 
 		ref, parseErr := registry.ParseReference(opts.RawReference)
 		if parseErr != nil {

From fa3adf1eeb73a1980b7cb6a011271a5ee48c1e8a Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 8 Jan 2024 03:18:09 +0000
Subject: [PATCH 21/42] resolve e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/manifest.go | 2 +-
 test/e2e/suite/command/repo.go     | 2 +-
 test/e2e/suite/command/tag.go      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/e2e/suite/command/manifest.go b/test/e2e/suite/command/manifest.go
index 6f7c10ebc..48e29356a 100644
--- a/test/e2e/suite/command/manifest.go
+++ b/test/e2e/suite/command/manifest.go
@@ -557,7 +557,7 @@ var _ = Describe("1.0 registry users:", func() {
 		It("should fail to fetch image if media type assertion fails", func() {
 			ORAS("manifest", "fetch", RegistryRef(FallbackHost, ImageRepo, multi_arch.LinuxAMD64.Digest.String()), "--media-type", "this.will.not.be.found").
 				ExpectFailure().
-				MatchErrKeyWords(multi_arch.LinuxAMD64.Digest.String(), "error: ", "not found").Exec()
+				MatchErrKeyWords(multi_arch.LinuxAMD64.Digest.String(), RegistryErrorPrefix, "not found").Exec()
 		})
 	})
 
diff --git a/test/e2e/suite/command/repo.go b/test/e2e/suite/command/repo.go
index 525884ca3..a505f50b1 100644
--- a/test/e2e/suite/command/repo.go
+++ b/test/e2e/suite/command/repo.go
@@ -42,7 +42,7 @@ var _ = Describe("ORAS beginners:", func() {
 			})
 
 			It("should fail listing repositories if wrong registry provided", func() {
-				ORAS("repo", "ls", RegistryRef(ZOTHost, ImageRepo, "some-tag")).ExpectFailure().MatchErrKeyWords("Error:").Exec()
+				ORAS("repo", "ls", RegistryRef(ZOTHost, ImageRepo, "some-tag")).ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix).Exec()
 			})
 
 			It("should fail and show detailed error description if no argument provided", func() {
diff --git a/test/e2e/suite/command/tag.go b/test/e2e/suite/command/tag.go
index 2fd556b9e..4532d7655 100644
--- a/test/e2e/suite/command/tag.go
+++ b/test/e2e/suite/command/tag.go
@@ -33,7 +33,7 @@ var _ = Describe("ORAS beginners:", func() {
 		})
 
 		It("should fail when provided manifest reference is not found", func() {
-			ORAS("tag", RegistryRef(ZOTHost, ImageRepo, InvalidTag), "tagged").ExpectFailure().MatchErrKeyWords("Error:").Exec()
+			ORAS("tag", RegistryRef(ZOTHost, ImageRepo, InvalidTag), "tagged").ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix).Exec()
 		})
 
 		It("should fail and show detailed error description if no argument provided", func() {

From cc42b046ba3be9b55f77b0a907f1361596776a15 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 8 Jan 2024 03:23:14 +0000
Subject: [PATCH 22/42] code clean

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 1 -
 cmd/oras/internal/option/target.go | 3 ---
 2 files changed, 4 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index e9bfb8947..7b66170ba 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -95,7 +95,6 @@ func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
 }
 
 // GetInner gets the inner error from the error response.
-// nil is returned if no valid inner error is found.
 func GetInner(err error, errResp *errcode.ErrorResponse) error {
 	inner := errResp.Errors
 	if len(inner) == 0 {
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index dafb0df60..2a9f43241 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -245,7 +245,6 @@ func (opts *Target) EnsureReferenceNotEmpty() error {
 
 // Handle handles error during cmd execution.
 func (opts *Target) Handle(err error, cmd *cobra.Command) (oerrors.Processor, error) {
-	// handle registry error
 	if opts.IsOCILayout {
 		return nil, err
 	}
@@ -268,9 +267,7 @@ func (opts *Target) Process(err error, callPath string) *oerrors.Error {
 
 	var errResp *errcode.ErrorResponse
 	if errors.As(err, &errResp) {
-		// remove HTTP related info
 		ret.Err = oerrors.GetInner(err, errResp)
-
 		ref, parseErr := registry.ParseReference(opts.RawReference)
 		if parseErr != nil {
 			// this should not happen

From 666c5186ef84964f701db7a9a106c3577074e811 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 8 Jan 2024 03:35:27 +0000
Subject: [PATCH 23/42] fix e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/repo.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/e2e/suite/command/repo.go b/test/e2e/suite/command/repo.go
index a505f50b1..cc0d06ab7 100644
--- a/test/e2e/suite/command/repo.go
+++ b/test/e2e/suite/command/repo.go
@@ -42,7 +42,7 @@ var _ = Describe("ORAS beginners:", func() {
 			})
 
 			It("should fail listing repositories if wrong registry provided", func() {
-				ORAS("repo", "ls", RegistryRef(ZOTHost, ImageRepo, "some-tag")).ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix).Exec()
+				ORAS("repo", "ls", RegistryRef(ZOTHost, ImageRepo, "some-tag")).ExpectFailure().MatchErrKeyWords("Error:").Exec()
 			})
 
 			It("should fail and show detailed error description if no argument provided", func() {
@@ -70,7 +70,7 @@ var _ = Describe("ORAS beginners:", func() {
 
 			It("should fail listing repositories if wrong registry provided", func() {
 				ORAS("repo", "tags").ExpectFailure().MatchErrKeyWords("Error:").Exec()
-				ORAS("repo", "tags", ZOTHost).ExpectFailure().MatchErrKeyWords("Error:").Exec()
+				ORAS("repo", "tags", ZOTHost).ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix).Exec()
 				ORAS("repo", "tags", RegistryRef(ZOTHost, ImageRepo, "some-tag")).ExpectFailure().MatchErrKeyWords("Error:").Exec()
 			})
 

From 028beb011bc08e4a89240901f955da8e3ec4b7f0 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 8 Jan 2024 03:46:04 +0000
Subject: [PATCH 24/42] fix e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/repo.go | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/e2e/suite/command/repo.go b/test/e2e/suite/command/repo.go
index cc0d06ab7..8bc924498 100644
--- a/test/e2e/suite/command/repo.go
+++ b/test/e2e/suite/command/repo.go
@@ -68,10 +68,10 @@ var _ = Describe("ORAS beginners:", func() {
 				ORAS("repository", "show-tags", "--help").MatchKeyWords(ExampleDesc).Exec()
 			})
 
-			It("should fail listing repositories if wrong registry provided", func() {
+			It("should fail listing repositories if wrong reference provided", func() {
 				ORAS("repo", "tags").ExpectFailure().MatchErrKeyWords("Error:").Exec()
-				ORAS("repo", "tags", ZOTHost).ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix).Exec()
-				ORAS("repo", "tags", RegistryRef(ZOTHost, ImageRepo, "some-tag")).ExpectFailure().MatchErrKeyWords("Error:").Exec()
+				ORAS("repo", "tags", ZOTHost).ExpectFailure().MatchErrKeyWords("Error:").Exec()
+				ORAS("repo", "tags", RegistryRef(ZOTHost, ImageRepo, "some-tag")).ExpectFailure().MatchErrKeyWords(RegistryErrorPrefix).Exec()
 			})
 
 			It("should fail and show detailed error description if no argument provided", func() {

From 716e62a8522e74075f2d30e53bab08ed3db4adaf Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Tue, 9 Jan 2024 03:38:06 +0000
Subject: [PATCH 25/42] resolve comment

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go      |  16 +-
 cmd/oras/internal/option/remote.go      |  30 +---
 cmd/oras/internal/option/target.go      |  41 ++---
 cmd/oras/internal/option/target_test.go | 223 ++++++++++++------------
 4 files changed, 135 insertions(+), 175 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index 7b66170ba..23ff98590 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -68,13 +68,8 @@ func CheckArgs(checker func(args []string) (bool, string), Usage string) cobra.P
 // Handler handles error during cmd execution.
 type Handler interface {
 	// Handle handles error during cmd execution.
-	// If returned processor is nil, error requires no further processing.
-	Handle(err error, cmd *cobra.Command) (Processor, error)
-}
-
-// Processor processes error.
-type Processor interface {
-	Process(err error, callPath string) *Error
+	// if nil is returned, then err cannot be handled.
+	Handle(err error, cmd *cobra.Command) error
 }
 
 // Command returns an error-handled cobra command.
@@ -85,11 +80,10 @@ func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
 		if err == nil {
 			return nil
 		}
-		processor, err := handler.Handle(err, cmd)
-		if processor == nil {
-			return err
+		if handled := handler.Handle(err, cmd); handled != nil {
+			return handled
 		}
-		return processor.Process(err, cmd.CommandPath())
+		return err
 	}
 	return cmd
 }
diff --git a/cmd/oras/internal/option/remote.go b/cmd/oras/internal/option/remote.go
index 906ca2835..45ce9c997 100644
--- a/cmd/oras/internal/option/remote.go
+++ b/cmd/oras/internal/option/remote.go
@@ -328,30 +328,16 @@ func (opts *Remote) isPlainHttp(registry string) bool {
 }
 
 // Handle handles error during cmd execution.
-func (opts *Remote) Handle(err error, cmd *cobra.Command) (oerrors.Processor, error) {
-	// handle not found error from registry
+func (opts *Remote) Handle(err error, cmd *cobra.Command) error {
+	var errResp *errcode.ErrorResponse
 	if errors.Is(err, errdef.ErrNotFound) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		return opts, err
-	}
-
-	// handle error response
-	var errResp *errcode.ErrorResponse
-	if errors.As(err, &errResp) {
+		return err
+	} else if errors.As(err, &errResp) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		return opts, err
-	}
-	return nil, err
-}
-
-// Process processes error into oerrors.Error.
-func (opts *Remote) Process(err error, _ string) *oerrors.Error {
-	ret := oerrors.Error{
-		Err: err,
-	}
-	var errResp *errcode.ErrorResponse
-	if errors.As(err, &errResp) {
-		ret.Err = oerrors.GetInner(err, errResp)
+		return &oerrors.Error{
+			Err: oerrors.GetInner(err, errResp),
+		}
 	}
-	return &ret
+	return nil
 }
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index 2a9f43241..dc65439a5 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -32,6 +32,7 @@ import (
 	"oras.land/oras-go/v2"
 	"oras.land/oras-go/v2/content"
 	"oras.land/oras-go/v2/content/oci"
+	"oras.land/oras-go/v2/errdef"
 	"oras.land/oras-go/v2/registry"
 	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras-go/v2/registry/remote/errcode"
@@ -244,45 +245,35 @@ func (opts *Target) EnsureReferenceNotEmpty() error {
 }
 
 // Handle handles error during cmd execution.
-func (opts *Target) Handle(err error, cmd *cobra.Command) (oerrors.Processor, error) {
+func (opts *Target) Handle(err error, cmd *cobra.Command) error {
 	if opts.IsOCILayout {
-		return nil, err
-	}
-
-	processor, err := opts.Remote.Handle(err, cmd)
-	if processor != nil {
-		processor = opts
+		return nil
 	}
-	return processor, err
-}
-
-// Process processes error into oerrors.Error.
-func (opts *Target) Process(err error, callPath string) *oerrors.Error {
-	ret := oerrors.Error{
+	ret := &oerrors.Error{
 		Err: err,
 	}
-	if opts.IsOCILayout {
-		return &ret
-	}
 
 	var errResp *errcode.ErrorResponse
-	if errors.As(err, &errResp) {
+	if errors.Is(err, errdef.ErrNotFound) {
+		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
+	} else if errors.As(err, &errResp) {
+		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
 		ret.Err = oerrors.GetInner(err, errResp)
 		ref, parseErr := registry.ParseReference(opts.RawReference)
 		if parseErr != nil {
 			// this should not happen
-			return &ret
+			return ret
 		}
 
 		if ref.Registry == "docker.io" && errResp.URL.Host == ref.Host() && errResp.StatusCode == http.StatusUnauthorized {
 			if ref.Repository != "" && !strings.Contains(ref.Repository, "/") {
 				// docker.io/xxx -> docker.io/library/xxx
 				ref.Repository = "library/" + ref.Repository
-				ret.Recommendation = fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", callPath, ref)
+				ret.Recommendation = fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", cmd.CommandPath(), ref)
 			}
 		}
 	}
-	return &ret
+	return ret
 }
 
 // BinaryTarget struct contains flags and arguments specifying two registries or
@@ -318,13 +309,9 @@ func (opts *BinaryTarget) Parse() error {
 }
 
 // Handle handles error during cmd execution.
-func (opts *BinaryTarget) Handle(err error, cmd *cobra.Command) (oerrors.Processor, error) {
-	if processor, err := opts.From.Handle(err, cmd); processor != nil {
-		if errResp, ok := err.(*errcode.ErrorResponse); ok {
-			if ref, _ := registry.ParseReference(opts.From.RawReference); errResp.URL.Host == ref.Host() {
-				return processor, err
-			}
-		}
+func (opts *BinaryTarget) Handle(err error, cmd *cobra.Command) error {
+	if err := opts.From.Handle(err, cmd); err != nil {
+		return err
 	}
 	return opts.To.Handle(err, cmd)
 }
diff --git a/cmd/oras/internal/option/target_test.go b/cmd/oras/internal/option/target_test.go
index f8271c64e..01d6fbcdb 100644
--- a/cmd/oras/internal/option/target_test.go
+++ b/cmd/oras/internal/option/target_test.go
@@ -16,14 +16,7 @@ limitations under the License.
 package option
 
 import (
-	"errors"
-	"net/http"
-	"net/url"
-	"reflect"
 	"testing"
-
-	"oras.land/oras-go/v2/registry/remote/errcode"
-	oerrors "oras.land/oras/cmd/oras/internal/errors"
 )
 
 func TestTarget_Parse_oci(t *testing.T) {
@@ -83,112 +76,112 @@ func Test_parseOCILayoutReference(t *testing.T) {
 	}
 }
 
-func TestTarget_Process_ociLayout(t *testing.T) {
-	errClient := errors.New("client error")
-	opts := &Target{
-		IsOCILayout: true,
-	}
-	if got := opts.Process(errClient, ""); got.Err != errClient || got.Recommendation != "" {
-		t.Errorf("unexpected output from Target.Process() = %v", got)
-	}
-}
+// func TestTarget_Process_ociLayout(t *testing.T) {
+// 	errClient := errors.New("client error")
+// 	opts := &Target{
+// 		IsOCILayout: true,
+// 	}
+// 	if got := opts.Process(errClient, ""); got.Err != errClient || got.Recommendation != "" {
+// 		t.Errorf("unexpected output from Target.Process() = %v", got)
+// 	}
+// }
 
-func TestTarget_Process_hint(t *testing.T) {
-	type fields struct {
-		Remote       Remote
-		RawReference string
-		Type         string
-		Reference    string
-		Path         string
-		IsOCILayout  bool
-	}
-	type args struct {
-		err      error
-		callPath string
-	}
-	errs := errcode.Errors{
-		errcode.Error{
-			Code:    "000",
-			Message: "mocked message",
-			Detail:  map[string]string{"mocked key": "mocked value"},
-		},
-	}
-	tests := []struct {
-		name   string
-		fields fields
-		args   args
-		want   *oerrors.Error
-	}{
-		{
-			"namespace already exists",
-			fields{RawReference: "docker.io/library/alpine:latest"},
-			args{
-				err: &errcode.ErrorResponse{
-					URL:        &url.URL{Host: "registry-1.docker.io"},
-					StatusCode: http.StatusUnauthorized,
-					Errors:     errs,
-				},
-			},
-			&oerrors.Error{Err: errs},
-		},
-		{
-			"no namespace",
-			fields{RawReference: "docker.io"},
-			args{
-				err: &errcode.ErrorResponse{
-					URL:        &url.URL{Host: "registry-1.docker.io"},
-					StatusCode: http.StatusUnauthorized,
-					Errors:     errs,
-				},
-			},
-			&oerrors.Error{Err: errs},
-		},
-		{
-			"not 401",
-			fields{RawReference: "docker.io"},
-			args{
-				err: &errcode.ErrorResponse{
-					URL:        &url.URL{Host: "registry-1.docker.io"},
-					StatusCode: http.StatusConflict,
-					Errors:     errs,
-				},
-			},
-			&oerrors.Error{Err: errs},
-		},
-		{
-			"should hint",
-			fields{
-				RawReference: "docker.io/alpine",
-				Path:         "oras test",
-			},
-			args{
-				err: &errcode.ErrorResponse{
-					URL:        &url.URL{Host: "registry-1.docker.io"},
-					StatusCode: http.StatusUnauthorized,
-					Errors:     errs,
-				},
-				callPath: "oras test",
-			},
-			&oerrors.Error{
-				Err:            errs,
-				Recommendation: "Namespace is missing, do you mean `oras test docker.io/library/alpine`?",
-			},
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			opts := &Target{
-				Remote:       tt.fields.Remote,
-				RawReference: tt.fields.RawReference,
-				Type:         tt.fields.Type,
-				Reference:    tt.fields.Reference,
-				Path:         tt.fields.Path,
-				IsOCILayout:  tt.fields.IsOCILayout,
-			}
-			got := opts.Process(tt.args.err, tt.args.callPath)
-			if !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("Target.Process() = %v, want %v", got, tt.want)
-			}
-		})
-	}
-}
+// func TestTarget_Process_hint(t *testing.T) {
+// 	type fields struct {
+// 		Remote       Remote
+// 		RawReference string
+// 		Type         string
+// 		Reference    string
+// 		Path         string
+// 		IsOCILayout  bool
+// 	}
+// 	type args struct {
+// 		err      error
+// 		callPath string
+// 	}
+// 	errs := errcode.Errors{
+// 		errcode.Error{
+// 			Code:    "000",
+// 			Message: "mocked message",
+// 			Detail:  map[string]string{"mocked key": "mocked value"},
+// 		},
+// 	}
+// 	tests := []struct {
+// 		name   string
+// 		fields fields
+// 		args   args
+// 		want   *oerrors.Error
+// 	}{
+// 		{
+// 			"namespace already exists",
+// 			fields{RawReference: "docker.io/library/alpine:latest"},
+// 			args{
+// 				err: &errcode.ErrorResponse{
+// 					URL:        &url.URL{Host: "registry-1.docker.io"},
+// 					StatusCode: http.StatusUnauthorized,
+// 					Errors:     errs,
+// 				},
+// 			},
+// 			&oerrors.Error{Err: errs},
+// 		},
+// 		{
+// 			"no namespace",
+// 			fields{RawReference: "docker.io"},
+// 			args{
+// 				err: &errcode.ErrorResponse{
+// 					URL:        &url.URL{Host: "registry-1.docker.io"},
+// 					StatusCode: http.StatusUnauthorized,
+// 					Errors:     errs,
+// 				},
+// 			},
+// 			&oerrors.Error{Err: errs},
+// 		},
+// 		{
+// 			"not 401",
+// 			fields{RawReference: "docker.io"},
+// 			args{
+// 				err: &errcode.ErrorResponse{
+// 					URL:        &url.URL{Host: "registry-1.docker.io"},
+// 					StatusCode: http.StatusConflict,
+// 					Errors:     errs,
+// 				},
+// 			},
+// 			&oerrors.Error{Err: errs},
+// 		},
+// 		{
+// 			"should hint",
+// 			fields{
+// 				RawReference: "docker.io/alpine",
+// 				Path:         "oras test",
+// 			},
+// 			args{
+// 				err: &errcode.ErrorResponse{
+// 					URL:        &url.URL{Host: "registry-1.docker.io"},
+// 					StatusCode: http.StatusUnauthorized,
+// 					Errors:     errs,
+// 				},
+// 				callPath: "oras test",
+// 			},
+// 			&oerrors.Error{
+// 				Err:            errs,
+// 				Recommendation: "Namespace is missing, do you mean `oras test docker.io/library/alpine`?",
+// 			},
+// 		},
+// 	}
+// 	for _, tt := range tests {
+// 		t.Run(tt.name, func(t *testing.T) {
+// 			opts := &Target{
+// 				Remote:       tt.fields.Remote,
+// 				RawReference: tt.fields.RawReference,
+// 				Type:         tt.fields.Type,
+// 				Reference:    tt.fields.Reference,
+// 				Path:         tt.fields.Path,
+// 				IsOCILayout:  tt.fields.IsOCILayout,
+// 			}
+// 			got := opts.Process(tt.args.err, tt.args.callPath)
+// 			if !reflect.DeepEqual(got, tt.want) {
+// 				t.Errorf("Target.Process() = %v, want %v", got, tt.want)
+// 			}
+// 		})
+// 	}
+// }

From 4503268cfbe4b9fce334953a096d64ebb45752f6 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Tue, 9 Jan 2024 03:42:27 +0000
Subject: [PATCH 26/42] code clean

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/remote.go | 2 +-
 cmd/oras/internal/option/target.go | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/cmd/oras/internal/option/remote.go b/cmd/oras/internal/option/remote.go
index 45ce9c997..13a8ae543 100644
--- a/cmd/oras/internal/option/remote.go
+++ b/cmd/oras/internal/option/remote.go
@@ -46,7 +46,7 @@ import (
 )
 
 // Remote options struct contains flags and arguments specifying one registry.
-// Remote implements oerrors.Handler and oerrors.Processor interface.
+// Remote implements oerrors.Handler and interface.
 type Remote struct {
 	DistributionSpec
 	CACertFilePath    string
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index dc65439a5..f5bab20a6 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -47,7 +47,7 @@ const (
 
 // Target struct contains flags and arguments specifying one registry or image
 // layout.
-// Target implements oerrors.Handler and oerrors.Processor interface.
+// Target implements oerrors.Handler interface.
 type Target struct {
 	Remote
 	RawReference string

From 9d299a93a75029c3594dac3970d604832ca39b2f Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Tue, 9 Jan 2024 03:56:05 +0000
Subject: [PATCH 27/42] bug fix

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target.go | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index f5bab20a6..b030f7f72 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -257,15 +257,19 @@ func (opts *Target) Handle(err error, cmd *cobra.Command) error {
 	if errors.Is(err, errdef.ErrNotFound) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
 	} else if errors.As(err, &errResp) {
-		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		ret.Err = oerrors.GetInner(err, errResp)
 		ref, parseErr := registry.ParseReference(opts.RawReference)
 		if parseErr != nil {
 			// this should not happen
 			return ret
 		}
+		if errResp.URL.Host != ref.Host() {
+			// not handle if the error is not from the target
+			return nil
+		}
+		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
+		ret.Err = oerrors.GetInner(err, errResp)
 
-		if ref.Registry == "docker.io" && errResp.URL.Host == ref.Host() && errResp.StatusCode == http.StatusUnauthorized {
+		if ref.Registry == "docker.io" && errResp.StatusCode == http.StatusUnauthorized {
 			if ref.Repository != "" && !strings.Contains(ref.Repository, "/") {
 				// docker.io/xxx -> docker.io/library/xxx
 				ref.Repository = "library/" + ref.Repository

From 3607c163e0fe4310c2d9329c7ad2beec3f92f5d8 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Tue, 9 Jan 2024 15:24:22 +0000
Subject: [PATCH 28/42] resolve comments

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 17 ++++++++---------
 cmd/oras/internal/option/remote.go | 13 +++++++------
 cmd/oras/internal/option/target.go | 14 +++++++-------
 3 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index 23ff98590..0b1449993 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -65,22 +65,21 @@ func CheckArgs(checker func(args []string) (bool, string), Usage string) cobra.P
 	}
 }
 
-// Handler handles error during cmd execution.
-type Handler interface {
-	// Handle handles error during cmd execution.
-	// if nil is returned, then err cannot be handled.
-	Handle(err error, cmd *cobra.Command) error
+// Modifier modifies the error during cmd execution.
+// If nil is returned, err should be used by caller.
+type Modifier interface {
+	Modify(cmd *cobra.Command, err error) error
 }
 
 // Command returns an error-handled cobra command.
-func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
+func Command(cmd *cobra.Command, handler Modifier) *cobra.Command {
 	runE := cmd.RunE
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
 		err := runE(cmd, args)
 		if err == nil {
 			return nil
 		}
-		if handled := handler.Handle(err, cmd); handled != nil {
+		if handled := handler.Modify(cmd, err); handled != nil {
 			return handled
 		}
 		return err
@@ -88,8 +87,8 @@ func Command(cmd *cobra.Command, handler Handler) *cobra.Command {
 	return cmd
 }
 
-// GetInner gets the inner error from the error response.
-func GetInner(err error, errResp *errcode.ErrorResponse) error {
+// Trim trims the error response detail from error message.
+func Trim(err error, errResp *errcode.ErrorResponse) error {
 	inner := errResp.Errors
 	if len(inner) == 0 {
 		return fmt.Errorf("empty response body: %w", errResp)
diff --git a/cmd/oras/internal/option/remote.go b/cmd/oras/internal/option/remote.go
index 13a8ae543..e960b191b 100644
--- a/cmd/oras/internal/option/remote.go
+++ b/cmd/oras/internal/option/remote.go
@@ -327,17 +327,18 @@ func (opts *Remote) isPlainHttp(registry string) bool {
 	return plainHTTP
 }
 
-// Handle handles error during cmd execution.
-func (opts *Remote) Handle(err error, cmd *cobra.Command) error {
-	var errResp *errcode.ErrorResponse
+// Modify modifies error during cmd execution.
+func (opts *Remote) Modify(cmd *cobra.Command, err error) error {
 	if errors.Is(err, errdef.ErrNotFound) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
 		return err
-	} else if errors.As(err, &errResp) {
+	}
+	var errResp *errcode.ErrorResponse
+	if errors.As(err, &errResp) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
 		return &oerrors.Error{
-			Err: oerrors.GetInner(err, errResp),
+			Err: oerrors.Trim(err, errResp),
 		}
 	}
-	return nil
+	return err
 }
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index b030f7f72..990a4d2cf 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -244,8 +244,8 @@ func (opts *Target) EnsureReferenceNotEmpty() error {
 	return nil
 }
 
-// Handle handles error during cmd execution.
-func (opts *Target) Handle(err error, cmd *cobra.Command) error {
+// Modify handles error during cmd execution.
+func (opts *Target) Modify(cmd *cobra.Command, err error) error {
 	if opts.IsOCILayout {
 		return nil
 	}
@@ -267,7 +267,7 @@ func (opts *Target) Handle(err error, cmd *cobra.Command) error {
 			return nil
 		}
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		ret.Err = oerrors.GetInner(err, errResp)
+		ret.Err = oerrors.Trim(err, errResp)
 
 		if ref.Registry == "docker.io" && errResp.StatusCode == http.StatusUnauthorized {
 			if ref.Repository != "" && !strings.Contains(ref.Repository, "/") {
@@ -312,10 +312,10 @@ func (opts *BinaryTarget) Parse() error {
 	return Parse(opts)
 }
 
-// Handle handles error during cmd execution.
-func (opts *BinaryTarget) Handle(err error, cmd *cobra.Command) error {
-	if err := opts.From.Handle(err, cmd); err != nil {
+// Modify handles error during cmd execution.
+func (opts *BinaryTarget) Modify(cmd *cobra.Command, err error) error {
+	if err := opts.From.Modify(cmd, err); err != nil {
 		return err
 	}
-	return opts.To.Handle(err, cmd)
+	return opts.To.Modify(cmd, err)
 }

From a9664b35e1b3cc1ad31fb0201cbf73d912830435 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 02:46:40 +0000
Subject: [PATCH 29/42] resolve comments

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 13 +++++--------
 cmd/oras/internal/option/remote.go |  8 ++++----
 cmd/oras/internal/option/target.go | 24 ++++++++++++------------
 3 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index 0b1449993..ab1947f0c 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -66,9 +66,8 @@ func CheckArgs(checker func(args []string) (bool, string), Usage string) cobra.P
 }
 
 // Modifier modifies the error during cmd execution.
-// If nil is returned, err should be used by caller.
 type Modifier interface {
-	Modify(cmd *cobra.Command, err error) error
+	Modify(cmd *cobra.Command, err error) (modifiedErr error, modified bool)
 }
 
 // Command returns an error-handled cobra command.
@@ -76,13 +75,11 @@ func Command(cmd *cobra.Command, handler Modifier) *cobra.Command {
 	runE := cmd.RunE
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
 		err := runE(cmd, args)
-		if err == nil {
-			return nil
+		if err != nil {
+			err, _ = handler.Modify(cmd, err)
+			return err
 		}
-		if handled := handler.Modify(cmd, err); handled != nil {
-			return handled
-		}
-		return err
+		return nil
 	}
 	return cmd
 }
diff --git a/cmd/oras/internal/option/remote.go b/cmd/oras/internal/option/remote.go
index e960b191b..67df6ab90 100644
--- a/cmd/oras/internal/option/remote.go
+++ b/cmd/oras/internal/option/remote.go
@@ -328,17 +328,17 @@ func (opts *Remote) isPlainHttp(registry string) bool {
 }
 
 // Modify modifies error during cmd execution.
-func (opts *Remote) Modify(cmd *cobra.Command, err error) error {
+func (opts *Remote) Modify(cmd *cobra.Command, err error) (error, bool) {
 	if errors.Is(err, errdef.ErrNotFound) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		return err
+		return err, true
 	}
 	var errResp *errcode.ErrorResponse
 	if errors.As(err, &errResp) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
 		return &oerrors.Error{
 			Err: oerrors.Trim(err, errResp),
-		}
+		}, true
 	}
-	return err
+	return err, false
 }
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index 990a4d2cf..8aa4ea594 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -245,29 +245,29 @@ func (opts *Target) EnsureReferenceNotEmpty() error {
 }
 
 // Modify handles error during cmd execution.
-func (opts *Target) Modify(cmd *cobra.Command, err error) error {
+func (opts *Target) Modify(cmd *cobra.Command, err error) (error, bool) {
 	if opts.IsOCILayout {
-		return nil
-	}
-	ret := &oerrors.Error{
-		Err: err,
+		return err, false
 	}
 
 	var errResp *errcode.ErrorResponse
 	if errors.Is(err, errdef.ErrNotFound) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
+		return err, true
 	} else if errors.As(err, &errResp) {
 		ref, parseErr := registry.ParseReference(opts.RawReference)
 		if parseErr != nil {
 			// this should not happen
-			return ret
+			return err, false
 		}
 		if errResp.URL.Host != ref.Host() {
 			// not handle if the error is not from the target
-			return nil
+			return err, false
 		}
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		ret.Err = oerrors.Trim(err, errResp)
+		ret := &oerrors.Error{
+			Err: oerrors.Trim(err, errResp),
+		}
 
 		if ref.Registry == "docker.io" && errResp.StatusCode == http.StatusUnauthorized {
 			if ref.Repository != "" && !strings.Contains(ref.Repository, "/") {
@@ -277,7 +277,7 @@ func (opts *Target) Modify(cmd *cobra.Command, err error) error {
 			}
 		}
 	}
-	return ret
+	return err, false
 }
 
 // BinaryTarget struct contains flags and arguments specifying two registries or
@@ -313,9 +313,9 @@ func (opts *BinaryTarget) Parse() error {
 }
 
 // Modify handles error during cmd execution.
-func (opts *BinaryTarget) Modify(cmd *cobra.Command, err error) error {
-	if err := opts.From.Modify(cmd, err); err != nil {
-		return err
+func (opts *BinaryTarget) Modify(cmd *cobra.Command, err error) (error, bool) {
+	if modifiedErr, modified := opts.From.Modify(cmd, err); modified {
+		return modifiedErr, modified
 	}
 	return opts.To.Modify(cmd, err)
 }

From 0131f020e2d69dd8bacb903dd275b364067d0b0e Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 03:09:26 +0000
Subject: [PATCH 30/42] bug fix

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 2 +-
 cmd/oras/internal/option/target.go | 1 +
 test/e2e/internal/utils/const.go   | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index ab1947f0c..afc83fbe2 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -88,7 +88,7 @@ func Command(cmd *cobra.Command, handler Modifier) *cobra.Command {
 func Trim(err error, errResp *errcode.ErrorResponse) error {
 	inner := errResp.Errors
 	if len(inner) == 0 {
-		return fmt.Errorf("empty response body: %w", errResp)
+		return fmt.Errorf("recognizable error message not found: %w", errResp)
 	} else {
 		errContent := err.Error()
 		errRespContent := errResp.Error()
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index 8aa4ea594..8ebb4ecc6 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -276,6 +276,7 @@ func (opts *Target) Modify(cmd *cobra.Command, err error) (error, bool) {
 				ret.Recommendation = fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", cmd.CommandPath(), ref)
 			}
 		}
+		return ret, true
 	}
 	return err, false
 }
diff --git a/test/e2e/internal/utils/const.go b/test/e2e/internal/utils/const.go
index f13d3a4de..6c247aa29 100644
--- a/test/e2e/internal/utils/const.go
+++ b/test/e2e/internal/utils/const.go
@@ -30,6 +30,6 @@ var (
 		"--image-spec",
 	}
 	RegistryErrorPrefix = "Error response from registry: "
-	EmptyBodyPrefix     = "empty response body: "
+	EmptyBodyPrefix     = "recognizable error message not found: "
 	InvalidTag          = "i-dont-think-this-tag-exists"
 )

From e47e0d3e5c3d5a802c71ecbec3c2332990cf69a5 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 03:25:22 +0000
Subject: [PATCH 31/42] add coverage

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/cp.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/test/e2e/suite/command/cp.go b/test/e2e/suite/command/cp.go
index ba09d4bef..a0838a10d 100644
--- a/test/e2e/suite/command/cp.go
+++ b/test/e2e/suite/command/cp.go
@@ -83,9 +83,16 @@ var _ = Describe("ORAS beginners:", func() {
 		})
 
 		It("should fail and show registry error prefix if target registry is not logged in", func() {
-			src := RegistryRef(ZOTHost, ArtifactRepo, foobar.Tag)
+			src := PrepareTempOCI(ArtifactRepo)
 			dst := RegistryRef(ZOTHost, cpTestRepo("dest-not-logged-in"), "")
-			ORAS("cp", src, dst, "--to-username", Username, "--to-password", Password+"?").
+			ORAS("cp", Flags.FromLayout, src, dst, "--to-username", Username, "--to-password", Password+"?").
+				MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
+		})
+
+		It("should fail and show registry error prefix if target registry is not logged in", func() {
+			src := RegistryRef(ZOTHost, cpTestRepo("dest-not-logged-in"), "")
+			dst := RegistryRef(ZOTHost, ArtifactRepo, foobar.Tag)
+			ORAS("cp", src, dst, "--from-username", Username, "--from-password", Password+"?").
 				MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
 		})
 	})

From 0494f779dbec799d46ed2adca6d2319196dc4dbd Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 03:39:45 +0000
Subject: [PATCH 32/42] add unit test

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target_test.go | 26 ++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/cmd/oras/internal/option/target_test.go b/cmd/oras/internal/option/target_test.go
index 01d6fbcdb..86e1316b5 100644
--- a/cmd/oras/internal/option/target_test.go
+++ b/cmd/oras/internal/option/target_test.go
@@ -16,7 +16,10 @@ limitations under the License.
 package option
 
 import (
+	"errors"
 	"testing"
+
+	"github.com/spf13/cobra"
 )
 
 func TestTarget_Parse_oci(t *testing.T) {
@@ -76,15 +79,20 @@ func Test_parseOCILayoutReference(t *testing.T) {
 	}
 }
 
-// func TestTarget_Process_ociLayout(t *testing.T) {
-// 	errClient := errors.New("client error")
-// 	opts := &Target{
-// 		IsOCILayout: true,
-// 	}
-// 	if got := opts.Process(errClient, ""); got.Err != errClient || got.Recommendation != "" {
-// 		t.Errorf("unexpected output from Target.Process() = %v", got)
-// 	}
-// }
+func TestTarget_Modify_ociLayout(t *testing.T) {
+	errClient := errors.New("client error")
+	opts := &Target{
+		IsOCILayout: true,
+	}
+	got, modified := opts.Modify(&cobra.Command{}, errClient)
+
+	if modified {
+		t.Errorf("expect error not to be modified but received true")
+	}
+	if got != errClient {
+		t.Errorf("unexpected output from Target.Process() = %v", got)
+	}
+}
 
 // func TestTarget_Process_hint(t *testing.T) {
 // 	type fields struct {

From 19b7ec13f8224d30058f32cbe15b9c8e3301f963 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 04:02:00 +0000
Subject: [PATCH 33/42] fix e2e

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 test/e2e/suite/command/cp.go | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/test/e2e/suite/command/cp.go b/test/e2e/suite/command/cp.go
index a0838a10d..c0bb31f57 100644
--- a/test/e2e/suite/command/cp.go
+++ b/test/e2e/suite/command/cp.go
@@ -82,16 +82,16 @@ var _ = Describe("ORAS beginners:", func() {
 			ORAS("cp", src, Flags.ToLayout, dst).MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
 		})
 
-		It("should fail and show registry error prefix if target registry is not logged in", func() {
+		It("should fail and show registry error prefix if destination registry is not logged in", func() {
 			src := PrepareTempOCI(ArtifactRepo)
 			dst := RegistryRef(ZOTHost, cpTestRepo("dest-not-logged-in"), "")
-			ORAS("cp", Flags.FromLayout, src, dst, "--to-username", Username, "--to-password", Password+"?").
+			ORAS("cp", Flags.FromLayout, LayoutRef(src, foobar.Tag), dst, "--to-username", Username, "--to-password", Password+"?").
 				MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
 		})
 
-		It("should fail and show registry error prefix if target registry is not logged in", func() {
-			src := RegistryRef(ZOTHost, cpTestRepo("dest-not-logged-in"), "")
-			dst := RegistryRef(ZOTHost, ArtifactRepo, foobar.Tag)
+		It("should fail and show registry error prefix if source registry is not logged in", func() {
+			src := RegistryRef(ZOTHost, cpTestRepo("src-not-logged-in"), foobar.Tag)
+			dst := RegistryRef(ZOTHost, ArtifactRepo, "")
 			ORAS("cp", src, dst, "--from-username", Username, "--from-password", Password+"?").
 				MatchErrKeyWords(RegistryErrorPrefix).ExpectFailure().Exec()
 		})

From e530def3c1726afbb13ead75e3cf168e5661d55d Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 05:19:08 +0000
Subject: [PATCH 34/42] fix full reference match and add UT

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target.go      |  26 ++--
 cmd/oras/internal/option/target_test.go | 199 ++++++++++++------------
 2 files changed, 117 insertions(+), 108 deletions(-)

diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index 8ebb4ecc6..bcf183da7 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -250,20 +250,28 @@ func (opts *Target) Modify(cmd *cobra.Command, err error) (error, bool) {
 		return err, false
 	}
 
-	var errResp *errcode.ErrorResponse
 	if errors.Is(err, errdef.ErrNotFound) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
 		return err, true
-	} else if errors.As(err, &errResp) {
-		ref, parseErr := registry.ParseReference(opts.RawReference)
-		if parseErr != nil {
-			// this should not happen
-			return err, false
-		}
+	}
+
+	var errResp *errcode.ErrorResponse
+	if errors.As(err, &errResp) {
+		ref := registry.Reference{Registry: opts.RawReference}
 		if errResp.URL.Host != ref.Host() {
-			// not handle if the error is not from the target
-			return err, false
+			// raw reference is not registry host
+			var parseErr error
+			ref, parseErr = registry.ParseReference(opts.RawReference)
+			if parseErr != nil {
+				// this should not happen
+				return err, false
+			}
+			if errResp.URL.Host != ref.Host() {
+				// not handle if the error is not from the target
+				return err, false
+			}
 		}
+
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
 		ret := &oerrors.Error{
 			Err: oerrors.Trim(err, errResp),
diff --git a/cmd/oras/internal/option/target_test.go b/cmd/oras/internal/option/target_test.go
index 86e1316b5..bbad419fb 100644
--- a/cmd/oras/internal/option/target_test.go
+++ b/cmd/oras/internal/option/target_test.go
@@ -17,9 +17,14 @@ package option
 
 import (
 	"errors"
+	"net/http"
+	"net/url"
+	"reflect"
 	"testing"
 
 	"github.com/spf13/cobra"
+	"oras.land/oras-go/v2/registry/remote/errcode"
+	oerrors "oras.land/oras/cmd/oras/internal/errors"
 )
 
 func TestTarget_Parse_oci(t *testing.T) {
@@ -94,102 +99,98 @@ func TestTarget_Modify_ociLayout(t *testing.T) {
 	}
 }
 
-// func TestTarget_Process_hint(t *testing.T) {
-// 	type fields struct {
-// 		Remote       Remote
-// 		RawReference string
-// 		Type         string
-// 		Reference    string
-// 		Path         string
-// 		IsOCILayout  bool
-// 	}
-// 	type args struct {
-// 		err      error
-// 		callPath string
-// 	}
-// 	errs := errcode.Errors{
-// 		errcode.Error{
-// 			Code:    "000",
-// 			Message: "mocked message",
-// 			Detail:  map[string]string{"mocked key": "mocked value"},
-// 		},
-// 	}
-// 	tests := []struct {
-// 		name   string
-// 		fields fields
-// 		args   args
-// 		want   *oerrors.Error
-// 	}{
-// 		{
-// 			"namespace already exists",
-// 			fields{RawReference: "docker.io/library/alpine:latest"},
-// 			args{
-// 				err: &errcode.ErrorResponse{
-// 					URL:        &url.URL{Host: "registry-1.docker.io"},
-// 					StatusCode: http.StatusUnauthorized,
-// 					Errors:     errs,
-// 				},
-// 			},
-// 			&oerrors.Error{Err: errs},
-// 		},
-// 		{
-// 			"no namespace",
-// 			fields{RawReference: "docker.io"},
-// 			args{
-// 				err: &errcode.ErrorResponse{
-// 					URL:        &url.URL{Host: "registry-1.docker.io"},
-// 					StatusCode: http.StatusUnauthorized,
-// 					Errors:     errs,
-// 				},
-// 			},
-// 			&oerrors.Error{Err: errs},
-// 		},
-// 		{
-// 			"not 401",
-// 			fields{RawReference: "docker.io"},
-// 			args{
-// 				err: &errcode.ErrorResponse{
-// 					URL:        &url.URL{Host: "registry-1.docker.io"},
-// 					StatusCode: http.StatusConflict,
-// 					Errors:     errs,
-// 				},
-// 			},
-// 			&oerrors.Error{Err: errs},
-// 		},
-// 		{
-// 			"should hint",
-// 			fields{
-// 				RawReference: "docker.io/alpine",
-// 				Path:         "oras test",
-// 			},
-// 			args{
-// 				err: &errcode.ErrorResponse{
-// 					URL:        &url.URL{Host: "registry-1.docker.io"},
-// 					StatusCode: http.StatusUnauthorized,
-// 					Errors:     errs,
-// 				},
-// 				callPath: "oras test",
-// 			},
-// 			&oerrors.Error{
-// 				Err:            errs,
-// 				Recommendation: "Namespace is missing, do you mean `oras test docker.io/library/alpine`?",
-// 			},
-// 		},
-// 	}
-// 	for _, tt := range tests {
-// 		t.Run(tt.name, func(t *testing.T) {
-// 			opts := &Target{
-// 				Remote:       tt.fields.Remote,
-// 				RawReference: tt.fields.RawReference,
-// 				Type:         tt.fields.Type,
-// 				Reference:    tt.fields.Reference,
-// 				Path:         tt.fields.Path,
-// 				IsOCILayout:  tt.fields.IsOCILayout,
-// 			}
-// 			got := opts.Process(tt.args.err, tt.args.callPath)
-// 			if !reflect.DeepEqual(got, tt.want) {
-// 				t.Errorf("Target.Process() = %v, want %v", got, tt.want)
-// 			}
-// 		})
-// 	}
-// }
+func TestTarget_Modify(t *testing.T) {
+	type fields struct {
+		Remote       Remote
+		RawReference string
+		Type         string
+		Reference    string
+		Path         string
+		IsOCILayout  bool
+	}
+	errs := errcode.Errors{
+		errcode.Error{
+			Code:    "000",
+			Message: "mocked message",
+			Detail:  map[string]string{"mocked key": "mocked value"},
+		},
+	}
+	tests := []struct {
+		name        string
+		fields      fields
+		err         error
+		modifiedErr *oerrors.Error
+	}{
+		{
+			"namespace already exists",
+			fields{RawReference: "docker.io/library/alpine:latest"},
+			&errcode.ErrorResponse{
+				URL:        &url.URL{Host: "registry-1.docker.io"},
+				StatusCode: http.StatusUnauthorized,
+				Errors:     errs,
+			},
+			&oerrors.Error{Err: errs},
+		},
+		{
+			"no namespace",
+			fields{RawReference: "docker.io"},
+			&errcode.ErrorResponse{
+				URL:        &url.URL{Host: "registry-1.docker.io"},
+				StatusCode: http.StatusUnauthorized,
+				Errors:     errs,
+			},
+			&oerrors.Error{Err: errs},
+		},
+		{
+			"not 401",
+			fields{RawReference: "docker.io"},
+			&errcode.ErrorResponse{
+				URL:        &url.URL{Host: "registry-1.docker.io"},
+				StatusCode: http.StatusConflict,
+				Errors:     errs,
+			},
+			&oerrors.Error{Err: errs},
+		},
+		{
+			"should hint",
+			fields{
+				RawReference: "docker.io/alpine",
+				Path:         "oras test",
+			},
+			&errcode.ErrorResponse{
+				URL:        &url.URL{Host: "registry-1.docker.io"},
+				StatusCode: http.StatusUnauthorized,
+				Errors:     errs,
+			},
+			&oerrors.Error{
+				Err:            errs,
+				Recommendation: "Namespace is missing, do you mean ` docker.io/library/alpine`?",
+			},
+		},
+	}
+
+	cmd := &cobra.Command{}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			opts := &Target{
+				Remote:       tt.fields.Remote,
+				RawReference: tt.fields.RawReference,
+				Type:         tt.fields.Type,
+				Reference:    tt.fields.Reference,
+				Path:         tt.fields.Path,
+				IsOCILayout:  tt.fields.IsOCILayout,
+			}
+			got, modified := opts.Modify(cmd, tt.err)
+			gotErr, ok := got.(*oerrors.Error)
+			if !ok {
+				t.Errorf("expecting error to be *oerrors.Error but received %T", got)
+			}
+			if !reflect.DeepEqual(gotErr.Err, tt.modifiedErr.Err) || gotErr.Usage != tt.modifiedErr.Usage || gotErr.Recommendation != tt.modifiedErr.Recommendation {
+				t.Errorf("Target.Modify() error = %v, wantErr %v", gotErr, tt.modifiedErr)
+			}
+			if !modified {
+				t.Errorf("Failed to modify %v", tt.err)
+			}
+		})
+	}
+}

From ff6a9bafe052d607722e200ace75c2147c1a7e58 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 05:30:18 +0000
Subject: [PATCH 35/42] cover more

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target_test.go | 41 ++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/cmd/oras/internal/option/target_test.go b/cmd/oras/internal/option/target_test.go
index bbad419fb..c021b86eb 100644
--- a/cmd/oras/internal/option/target_test.go
+++ b/cmd/oras/internal/option/target_test.go
@@ -99,7 +99,46 @@ func TestTarget_Modify_ociLayout(t *testing.T) {
 	}
 }
 
-func TestTarget_Modify(t *testing.T) {
+func TestTarget_Modify_errInvalidReference(t *testing.T) {
+	errClient := errors.New("client error")
+	opts := &Target{
+		IsOCILayout:  true,
+		RawReference: "invalid-reference",
+	}
+	got, modified := opts.Modify(&cobra.Command{}, errClient)
+
+	if modified {
+		t.Errorf("expect error not to be modified but received true")
+	}
+	if got != errClient {
+		t.Errorf("unexpected output from Target.Process() = %v", got)
+	}
+}
+
+func TestTarget_Modify_errHostNotMatching(t *testing.T) {
+	errResp := &errcode.ErrorResponse{
+		URL:        &url.URL{Host: "registry-1.docker.io"},
+		StatusCode: http.StatusUnauthorized,
+		Errors: errcode.Errors{
+			errcode.Error{
+				Code:    "000",
+				Message: "mocked message",
+				Detail:  map[string]string{"mocked key": "mocked value"},
+			},
+		},
+	}
+
+	opts := &Target{
+		IsOCILayout:  true,
+		RawReference: "registry-2.docker.io/test:tag",
+	}
+	_, modified := opts.Modify(&cobra.Command{}, errResp)
+	if modified {
+		t.Errorf("expect error not to be modified but received true")
+	}
+}
+
+func TestTarget_Modify_dockerHint(t *testing.T) {
 	type fields struct {
 		Remote       Remote
 		RawReference string

From b12d29ec6b88f2f27acb49f578c2c3e512a90810 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 05:31:54 +0000
Subject: [PATCH 36/42] code clean

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/remote.go | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/cmd/oras/internal/option/remote.go b/cmd/oras/internal/option/remote.go
index 67df6ab90..255393934 100644
--- a/cmd/oras/internal/option/remote.go
+++ b/cmd/oras/internal/option/remote.go
@@ -329,10 +329,6 @@ func (opts *Remote) isPlainHttp(registry string) bool {
 
 // Modify modifies error during cmd execution.
 func (opts *Remote) Modify(cmd *cobra.Command, err error) (error, bool) {
-	if errors.Is(err, errdef.ErrNotFound) {
-		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)
-		return err, true
-	}
 	var errResp *errcode.ErrorResponse
 	if errors.As(err, &errResp) {
 		cmd.SetErrPrefix(oerrors.RegistryErrorPrefix)

From ce2582aa419b976e1dc7550ca77a7892d23c1bba Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 06:01:52 +0000
Subject: [PATCH 37/42] add TODO

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index afc83fbe2..b2b12e240 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -90,6 +90,8 @@ func Trim(err error, errResp *errcode.ErrorResponse) error {
 	if len(inner) == 0 {
 		return fmt.Errorf("recognizable error message not found: %w", errResp)
 	} else {
+		// TODO: trim dedicated error type when
+		// https://github.com/oras-project/oras-go/issues/677 is done
 		errContent := err.Error()
 		errRespContent := errResp.Error()
 		if idx := strings.Index(errContent, errRespContent); idx > 0 {

From 7c9933062e4918b3ad5d7aa4ede33a698c564319 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 06:06:50 +0000
Subject: [PATCH 38/42] add coverage

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target_test.go | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/cmd/oras/internal/option/target_test.go b/cmd/oras/internal/option/target_test.go
index c021b86eb..1006edf1c 100644
--- a/cmd/oras/internal/option/target_test.go
+++ b/cmd/oras/internal/option/target_test.go
@@ -86,9 +86,7 @@ func Test_parseOCILayoutReference(t *testing.T) {
 
 func TestTarget_Modify_ociLayout(t *testing.T) {
 	errClient := errors.New("client error")
-	opts := &Target{
-		IsOCILayout: true,
-	}
+	opts := &Target{}
 	got, modified := opts.Modify(&cobra.Command{}, errClient)
 
 	if modified {
@@ -102,7 +100,6 @@ func TestTarget_Modify_ociLayout(t *testing.T) {
 func TestTarget_Modify_errInvalidReference(t *testing.T) {
 	errClient := errors.New("client error")
 	opts := &Target{
-		IsOCILayout:  true,
 		RawReference: "invalid-reference",
 	}
 	got, modified := opts.Modify(&cobra.Command{}, errClient)

From 162a9dc9e5d43a36a694b47b3cff73e6cba25f50 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 06:37:34 +0000
Subject: [PATCH 39/42] increase coverage

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target_test.go | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/cmd/oras/internal/option/target_test.go b/cmd/oras/internal/option/target_test.go
index 1006edf1c..40a6f058f 100644
--- a/cmd/oras/internal/option/target_test.go
+++ b/cmd/oras/internal/option/target_test.go
@@ -98,16 +98,26 @@ func TestTarget_Modify_ociLayout(t *testing.T) {
 }
 
 func TestTarget_Modify_errInvalidReference(t *testing.T) {
-	errClient := errors.New("client error")
+	errResp := &errcode.ErrorResponse{
+		URL:        &url.URL{Host: "registry-1.docker.io"},
+		StatusCode: http.StatusUnauthorized,
+		Errors: errcode.Errors{
+			errcode.Error{
+				Code:    "000",
+				Message: "mocked message",
+				Detail:  map[string]string{"mocked key": "mocked value"},
+			},
+		},
+	}
 	opts := &Target{
 		RawReference: "invalid-reference",
 	}
-	got, modified := opts.Modify(&cobra.Command{}, errClient)
+	got, modified := opts.Modify(&cobra.Command{}, errResp)
 
 	if modified {
 		t.Errorf("expect error not to be modified but received true")
 	}
-	if got != errClient {
+	if got != errResp {
 		t.Errorf("unexpected output from Target.Process() = %v", got)
 	}
 }
@@ -126,7 +136,6 @@ func TestTarget_Modify_errHostNotMatching(t *testing.T) {
 	}
 
 	opts := &Target{
-		IsOCILayout:  true,
 		RawReference: "registry-2.docker.io/test:tag",
 	}
 	_, modified := opts.Modify(&cobra.Command{}, errResp)

From c15c3f5c63f4b02dc7fb9da9eda475a0624d46a4 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Thu, 11 Jan 2024 10:37:23 +0000
Subject: [PATCH 40/42] refactor trimming

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 43 +++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 13 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index b2b12e240..11e66b4fc 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -84,24 +84,41 @@ func Command(cmd *cobra.Command, handler Modifier) *cobra.Command {
 	return cmd
 }
 
-// Trim trims the error response detail from error message.
-func Trim(err error, errResp *errcode.ErrorResponse) error {
-	inner := errResp.Errors
-	if len(inner) == 0 {
-		return fmt.Errorf("recognizable error message not found: %w", errResp)
-	} else {
-		// TODO: trim dedicated error type when
-		// https://github.com/oras-project/oras-go/issues/677 is done
-		errContent := err.Error()
-		errRespContent := errResp.Error()
-		if idx := strings.Index(errContent, errRespContent); idx > 0 {
-			// remove HTTP related info
-			return fmt.Errorf("%s%w", errContent[:idx], inner)
+// Trim tries to trim toTrim from err.
+func Trim(err error, toTrim error) error {
+	var inner error
+	if errResp, ok := toTrim.(*errcode.ErrorResponse); ok {
+		if len(errResp.Errors) == 0 {
+			return fmt.Errorf("recognizable error message not found: %w", toTrim)
 		}
+		inner = errResp.Errors
+	} else {
+		return err
+	}
+
+	if rewrapped := reWrap(err, toTrim, inner); rewrapped != nil {
+		return rewrapped
 	}
 	return inner
 }
 
+// reWrap re-wraps errA to errC and trims out errB, returns nil if scrub fails.
+// +---------- errA ----------+
+// |         +---- errB ----+ |      +---- errA ----+
+// |         |    errC      | |  =>  |     errC     |
+// |         +--------------+ |      +--------------+
+// +--------------------------+
+func reWrap(errA error, errB error, errC error) error {
+	// TODO: trim dedicated error type when
+	// https://github.com/oras-project/oras-go/issues/677 is done
+	contentA := errA.Error()
+	contentB := errB.Error()
+	if idx := strings.Index(contentA, contentB); idx > 0 {
+		return fmt.Errorf("%s%w", contentA[:idx], errC)
+	}
+	return nil
+}
+
 // NewErrEmptyTagOrDigest creates a new error based on the reference string.
 func NewErrEmptyTagOrDigest(ref registry.Reference) error {
 	return NewErrEmptyTagOrDigestStr(ref.String())

From ddc979496cd31c299972ad205ace7733ae4a8c7e Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 15 Jan 2024 08:29:15 +0000
Subject: [PATCH 41/42] resolve comments

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/errors/errors.go | 2 +-
 cmd/oras/internal/option/target.go | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/cmd/oras/internal/errors/errors.go b/cmd/oras/internal/errors/errors.go
index 11e66b4fc..8af80303d 100644
--- a/cmd/oras/internal/errors/errors.go
+++ b/cmd/oras/internal/errors/errors.go
@@ -108,7 +108,7 @@ func Trim(err error, toTrim error) error {
 // |         |    errC      | |  =>  |     errC     |
 // |         +--------------+ |      +--------------+
 // +--------------------------+
-func reWrap(errA error, errB error, errC error) error {
+func reWrap(errA, errB, errC error) error {
 	// TODO: trim dedicated error type when
 	// https://github.com/oras-project/oras-go/issues/677 is done
 	contentA := errA.Error()
diff --git a/cmd/oras/internal/option/target.go b/cmd/oras/internal/option/target.go
index bcf183da7..d4b8878fc 100644
--- a/cmd/oras/internal/option/target.go
+++ b/cmd/oras/internal/option/target.go
@@ -281,7 +281,7 @@ func (opts *Target) Modify(cmd *cobra.Command, err error) (error, bool) {
 			if ref.Repository != "" && !strings.Contains(ref.Repository, "/") {
 				// docker.io/xxx -> docker.io/library/xxx
 				ref.Repository = "library/" + ref.Repository
-				ret.Recommendation = fmt.Sprintf("Namespace is missing, do you mean `%s %s`?", cmd.CommandPath(), ref)
+				ret.Recommendation = fmt.Sprintf("Namespace seems missing. Do you mean `%s %s`?", cmd.CommandPath(), ref)
 			}
 		}
 		return ret, true

From e602b8980feacd5a791e38fb9a21de2976a3d9f7 Mon Sep 17 00:00:00 2001
From: Billy Zha <jinzha1@microsoft.com>
Date: Mon, 15 Jan 2024 09:02:55 +0000
Subject: [PATCH 42/42] fix unit test

Signed-off-by: Billy Zha <jinzha1@microsoft.com>
---
 cmd/oras/internal/option/target_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/oras/internal/option/target_test.go b/cmd/oras/internal/option/target_test.go
index 40a6f058f..8ab6f8459 100644
--- a/cmd/oras/internal/option/target_test.go
+++ b/cmd/oras/internal/option/target_test.go
@@ -209,7 +209,7 @@ func TestTarget_Modify_dockerHint(t *testing.T) {
 			},
 			&oerrors.Error{
 				Err:            errs,
-				Recommendation: "Namespace is missing, do you mean ` docker.io/library/alpine`?",
+				Recommendation: "Namespace seems missing. Do you mean ` docker.io/library/alpine`?",
 			},
 		},
 	}