Add types.Image.EmbeddedDockerReferenceConflicts

This allows us to detect whether we need to edit the reference before
trying to (i.e. before uploading any of the layers).  The method
interface may be a bit surprising, it is designed to hide the
complexity and schema1 specifics in manifestSchema1; see the comment
in that implementation for more details.

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

copy/manifest_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/containers/image/docker/reference"
 	"github.com/containers/image/manifest"
 	"github.com/containers/image/types"
 	"github.com/opencontainers/image-spec/specs-go/v1"
@@ -57,6 +58,9 @@ func (f fakeImageSource) OCIConfig() (*v1.Image, error) {
 func (f fakeImageSource) LayerInfos() []types.BlobInfo {
 	panic("Unexpected call to a mock function")
 }
+func (f fakeImageSource) EmbeddedDockerReferenceConflicts(ref reference.Named) bool {
+	panic("Unexpected call to a mock function")
+}
 func (f fakeImageSource) Inspect() (*types.ImageInspectInfo, error) {
 	panic("Unexpected call to a mock function")
 }

image/docker_schema1.go

@@ -135,6 +135,27 @@ func (m *manifestSchema1) LayerInfos() []types.BlobInfo {
 	return layers
 }
 
+// EmbeddedDockerReferenceConflicts whether a Docker reference embedded in the manifest, if any, conflicts with destination ref.
+// It returns false if the manifest does not embed a Docker reference.
+// (This embedding unfortunately happens for Docker schema1, please do not add support for this in any new formats.)
+func (m *manifestSchema1) EmbeddedDockerReferenceConflicts(ref reference.Named) bool {
+	// This is a bit convoluted: We can’t just have a "get embedded docker reference" method
+	// and have the “does it conflict” logic in the generic copy code, because the manifest does not actually
+	// embed a full docker/distribution reference, but only the repo name and tag (without the host name).
+	// So we would have to provide a “return repo without host name, and tag” getter for the generic code,
+	// which would be very awkward.  Instead, we do the matching here in schema1-specific code, and all the
+	// generic copy code needs to know about is reference.Named and that a manifest may need updating
+	// for some destinations.
+	name := reference.Path(ref)
+	var tag string
+	if tagged, isTagged := ref.(reference.NamedTagged); isTagged {
+		tag = tagged.Tag()
+	} else {
+		tag = ""
+	}
+	return m.Name != name || m.Tag != tag
+}
+
 func (m *manifestSchema1) imageInspectInfo() (*types.ImageInspectInfo, error) {
 	v1 := &v1Image{}
 	if err := json.Unmarshal([]byte(m.History[0].V1Compatibility), v1); err != nil {

image/docker_schema2.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	"github.com/Sirupsen/logrus"
+	"github.com/containers/image/docker/reference"
 	"github.com/containers/image/manifest"
 	"github.com/containers/image/types"
 	"github.com/opencontainers/go-digest"
@@ -140,6 +141,13 @@ func (m *manifestSchema2) LayerInfos() []types.BlobInfo {
 	return blobs
 }
 
+// EmbeddedDockerReferenceConflicts whether a Docker reference embedded in the manifest, if any, conflicts with destination ref.
+// It returns false if the manifest does not embed a Docker reference.
+// (This embedding unfortunately happens for Docker schema1, please do not add support for this in any new formats.)
+func (m *manifestSchema2) EmbeddedDockerReferenceConflicts(ref reference.Named) bool {
+	return false
+}
+
 func (m *manifestSchema2) imageInspectInfo() (*types.ImageInspectInfo, error) {
 	config, err := m.ConfigBlob()
 	if err != nil {

image/docker_schema2_test.go

@@ -242,6 +242,20 @@ func TestManifestSchema2LayerInfo(t *testing.T) {
 	}
 }
 
+func TestManifestSchema2EmbeddedDockerReferenceConflicts(t *testing.T) {
+	for _, m := range []genericManifest{
+		manifestSchema2FromFixture(t, unusedImageSource{}, "schema2.json"),
+		manifestSchema2FromComponentsLikeFixture(nil),
+	} {
+		for _, name := range []string{"busybox", "example.com:5555/ns/repo:tag"} {
+			ref, err := reference.ParseNormalizedNamed(name)
+			require.NoError(t, err)
+			conflicts := m.EmbeddedDockerReferenceConflicts(ref)
+			assert.False(t, conflicts)
+		}
+	}
+}
+
 func TestManifestSchema2ImageInspectInfo(t *testing.T) {
 	configJSON, err := ioutil.ReadFile("fixtures/schema2-config.json")
 	require.NoError(t, err)

image/manifest.go

@@ -3,6 +3,7 @@ package image
 import (
 	"time"
 
+	"github.com/containers/image/docker/reference"
 	"github.com/containers/image/manifest"
 	"github.com/containers/image/pkg/strslice"
 	"github.com/containers/image/types"
@@ -72,6 +73,10 @@ type genericManifest interface {
 	// The Digest field is guaranteed to be provided; Size may be -1.
 	// WARNING: The list may contain duplicates, and they are semantically relevant.
 	LayerInfos() []types.BlobInfo
+	// EmbeddedDockerReferenceConflicts whether a Docker reference embedded in the manifest, if any, conflicts with destination ref.
+	// It returns false if the manifest does not embed a Docker reference.
+	// (This embedding unfortunately happens for Docker schema1, please do not add support for this in any new formats.)
+	EmbeddedDockerReferenceConflicts(ref reference.Named) bool
 	imageInspectInfo() (*types.ImageInspectInfo, error) // To be called by inspectManifest
 	// UpdatedImageNeedsLayerDiffIDs returns true iff UpdatedImage(options) needs InformationOnly.LayerDiffIDs.
 	// This is a horribly specific interface, but computing InformationOnly.LayerDiffIDs can be very expensive to compute

image/oci.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"io/ioutil"
 
+	"github.com/containers/image/docker/reference"
 	"github.com/containers/image/manifest"
 	"github.com/containers/image/types"
 	"github.com/opencontainers/go-digest"
@@ -107,6 +108,13 @@ func (m *manifestOCI1) LayerInfos() []types.BlobInfo {
 	return blobs
 }
 
+// EmbeddedDockerReferenceConflicts whether a Docker reference embedded in the manifest, if any, conflicts with destination ref.
+// It returns false if the manifest does not embed a Docker reference.
+// (This embedding unfortunately happens for Docker schema1, please do not add support for this in any new formats.)
+func (m *manifestOCI1) EmbeddedDockerReferenceConflicts(ref reference.Named) bool {
+	return false
+}
+
 func (m *manifestOCI1) imageInspectInfo() (*types.ImageInspectInfo, error) {
 	config, err := m.ConfigBlob()
 	if err != nil {

image/oci_test.go

@@ -207,6 +207,20 @@ func TestManifestOCI1LayerInfo(t *testing.T) {
 	}
 }
 
+func TestManifestOCI1EmbeddedDockerReferenceConflicts(t *testing.T) {
+	for _, m := range []genericManifest{
+		manifestOCI1FromFixture(t, unusedImageSource{}, "oci1.json"),
+		manifestOCI1FromComponentsLikeFixture(nil),
+	} {
+		for _, name := range []string{"busybox", "example.com:5555/ns/repo:tag"} {
+			ref, err := reference.ParseNormalizedNamed(name)
+			require.NoError(t, err)
+			conflicts := m.EmbeddedDockerReferenceConflicts(ref)
+			assert.False(t, conflicts)
+		}
+	}
+}
+
 func TestManifestOCI1ImageInspectInfo(t *testing.T) {
 	configJSON, err := ioutil.ReadFile("fixtures/oci1-config.json")
 	require.NoError(t, err)

types/types.go

@@ -226,6 +226,10 @@ type Image interface {
 	// The Digest field is guaranteed to be provided; Size may be -1.
 	// WARNING: The list may contain duplicates, and they are semantically relevant.
 	LayerInfos() []BlobInfo
+	// EmbeddedDockerReferenceConflicts whether a Docker reference embedded in the manifest, if any, conflicts with destination ref.
+	// It returns false if the manifest does not embed a Docker reference.
+	// (This embedding unfortunately happens for Docker schema1, please do not add support for this in any new formats.)
+	EmbeddedDockerReferenceConflicts(ref reference.Named) bool
 	// Inspect returns various information for (skopeo inspect) parsed from the manifest and configuration.
 	Inspect() (*ImageInspectInfo, error)
 	// UpdatedImageNeedsLayerDiffIDs returns true iff UpdatedImage(options) needs InformationOnly.LayerDiffIDs.