Don't format to string and re-parse a DockerReference()

We already have a c/image/docker/reference.Named; no need to
round-trip it through a string.  This also eliminates the theoretical
parsing failure, and the unchecked .(reference.Named) cast.

Also add a check for DockerReference() == nil to be extra paranoid,
although that should never happen.

Should not change behavior (but does not add unit tests).

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

Closes: #1176
Approved by: rhatdan

2 files changed, 11 insertions, 8 deletions

diff --git a/libpod/image/image.go b/libpod/image/image.go
index 914b8f754..3abaecc6c 100644
--- a/libpod/image/image.go
+++ b/libpod/image/image.go
@@ -15,6 +15,7 @@ import (
 	"github.com/containers/image/manifest"
 	is "github.com/containers/image/storage"
 	"github.com/containers/image/tarball"
+	"github.com/containers/image/transports"
 	"github.com/containers/image/transports/alltransports"
 	"github.com/containers/image/types"
 	"github.com/containers/storage"
@@ -552,11 +553,11 @@ func (i *Image) PushImage(ctx context.Context, destination, manifestMIMEType, au
 	}
 	copyOptions := getCopyOptions(writer, signaturePolicyPath, nil, dockerRegistryOptions, signingOptions, authFile, manifestMIMEType, forceCompress, additionalDockerArchiveTags)
 	if dest.Transport().Name() == DockerTransport {
-		imgRef, err := reference.Parse(dest.DockerReference().String())
-		if err != nil {
-			return err
+		imgRef := dest.DockerReference()
+		if imgRef == nil { // This should never happen; such references can’t be created.
+			return fmt.Errorf("internal error: DockerTransport reference %s does not have a DockerReference", transports.ImageName(dest))
 		}
-		registry := reference.Domain(imgRef.(reference.Named))
+		registry := reference.Domain(imgRef)
 
 		if util.StringInSlice(registry, insecureRegistries) && !forceSecure {
 			copyOptions.DestinationCtx.DockerInsecureSkipTLSVerify = true
diff --git a/libpod/image/pull.go b/libpod/image/pull.go
index 69c7de6ff..43d1ab837 100644
--- a/libpod/image/pull.go
+++ b/libpod/image/pull.go
@@ -16,6 +16,7 @@ import (
 	"github.com/containers/image/pkg/sysregistries"
 	is "github.com/containers/image/storage"
 	"github.com/containers/image/tarball"
+	"github.com/containers/image/transports"
 	"github.com/containers/image/transports/alltransports"
 	"github.com/containers/image/types"
 	"github.com/pkg/errors"
@@ -207,11 +208,12 @@ func (i *Image) pullImage(ctx context.Context, writer io.Writer, authfile, signa
 	for _, imageInfo := range pullRefPairs {
 		copyOptions := getCopyOptions(writer, signaturePolicyPath, dockerOptions, nil, signingOptions, authfile, "", false, nil)
 		if imageInfo.srcRef.Transport().Name() == DockerTransport {
-			imgRef, err := reference.Parse(imageInfo.srcRef.DockerReference().String())
-			if err != nil {
-				return nil, err
+			imgRef := imageInfo.srcRef.DockerReference()
+			if imgRef == nil { // This should never happen; such references can’t be created.
+				return nil, fmt.Errorf("internal error: DockerTransport reference %s does not have a DockerReference",
+					transports.ImageName(imageInfo.srcRef))
 			}
-			registry := reference.Domain(imgRef.(reference.Named))
+			registry := reference.Domain(imgRef)
 
 			if util.StringInSlice(registry, insecureRegistries) && !forceSecure {
 				copyOptions.SourceCtx.DockerInsecureSkipTLSVerify = true