cmd/utils, pkg/utils: Improve an error message for the image option

containers#937

src/cmd/utils.go

@@ -112,6 +112,16 @@ func createErrorInvalidImageForContainerName(container string) error {
 	return errors.New(errMsg)
 }
 
+func createErrorInvalidImageWithoutBasename() error {
+	var builder strings.Builder
+	fmt.Fprintf(&builder, "invalid argument for '--image'\n")
+	fmt.Fprintf(&builder, "Images must have basenames.\n")
+	fmt.Fprintf(&builder, "Run '%s --help' for usage.", executableBase)
+
+	errMsg := builder.String()
+	return errors.New(errMsg)
+}
+
 func createErrorInvalidRelease(hint string) error {
 	var builder strings.Builder
 	fmt.Fprintf(&builder, "invalid argument for '--release'\n")
@@ -143,6 +153,7 @@ func resolveContainerAndImageNames(container, containerArg, distroCLI, imageCLI,
 	if err != nil {
 		var errContainer *utils.ContainerError
 		var errDistro *utils.DistroError
+		var errImage *utils.ImageError
 		var errParseRelease *utils.ParseReleaseError
 
 		if errors.As(err, &errContainer) {
@@ -172,6 +183,14 @@ func resolveContainerAndImageNames(container, containerArg, distroCLI, imageCLI,
 				panicMsg := fmt.Sprintf("unexpected %T: %s", err, err)
 				panic(panicMsg)
 			}
+		} else if errors.As(err, &errImage) {
+			if errors.Is(err, utils.ErrImageWithoutBasename) {
+				err := createErrorInvalidImageWithoutBasename()
+				return "", "", "", err
+			} else {
+				panicMsg := fmt.Sprintf("unexpected %T: %s", err, err)
+				panic(panicMsg)
+			}
 		} else if errors.As(err, &errParseRelease) {
 			err := createErrorInvalidRelease(errParseRelease.Hint)
 			return "", "", "", err

src/pkg/utils/errors.go

@@ -31,6 +31,11 @@ type DistroError struct {
 	Err    error
 }
 
+type ImageError struct {
+	Image string
+	Err   error
+}
+
 type ParseReleaseError struct {
 	Hint string
 }
@@ -53,6 +58,15 @@ func (err *DistroError) Unwrap() error {
 	return err.Err
 }
 
+func (err *ImageError) Error() string {
+	errMsg := fmt.Sprintf("%s: %s", err.Image, err.Err)
+	return errMsg
+}
+
+func (err *ImageError) Unwrap() error {
+	return err.Err
+}
+
 func (err *ParseReleaseError) Error() string {
 	return err.Hint
 }

src/pkg/utils/utils.go

@@ -125,6 +125,8 @@ var (
 	ErrDistroUnsupported = errors.New("distribution is unsupported")
 
 	ErrDistroWithoutRelease = errors.New("non-default distribution must specify release")
+
+	ErrImageWithoutBasename = errors.New("image does not have a basename")
 )
 
 func init() {
@@ -239,7 +241,7 @@ func GetCgroupsVersion() (int, error) {
 func getContainerNamePrefixForImage(image string) (string, error) {
 	basename := ImageReferenceGetBasename(image)
 	if basename == "" {
-		return "", fmt.Errorf("failed to get the basename of image %s", image)
+		return "", &ImageError{image, ErrImageWithoutBasename}
 	}
 
 	for _, distroObj := range supportedDistros {