moby · thaJeztah · Aug 29, 2024 · Aug 29, 2024
diff --git a/daemon/containerd/image_list.go b/daemon/containerd/image_list.go
@@ -393,17 +393,25 @@ func (i *ImageService) imageSummary(ctx context.Context, img images.Image, platf
 				"error": err,
 				"image": img.Name,
 			}).Warn("unexpected image target (neither a manifest nor index)")
-			return nil, nil, nil
+		} else {
+			return nil, nil, err
 		}
-		return nil, nil, err
 	}
 
 	if best == nil {
-		// TODO we should probably show *something* for images we've pulled
-		// but are 100% shallow or an empty manifest list/index
-		// ("tianon/scratch:index" is an empty example image index and
-		// "tianon/scratch:list" is an empty example manifest list)
-		return nil, nil, nil
+		target := img.Target
+		return &imagetypes.Summary{
+			ID:          target.Digest.String(),
+			RepoDigests: []string{target.Digest.String()},
+			RepoTags:    tagsByDigest[target.Digest],
+			Size:        totalSize,
+			// -1 indicates that the value has not been set (avoids ambiguity
+			// between 0 (default) and "not set". We cannot use a pointer (nil)
+			// for this, as the JSON representation uses "omitempty", which would
+			// consider both "0" and "nil" to be "empty".
+			SharedSize: -1,
+			Containers: -1,
+		}, nil, nil
 	}
 
 	image, err := i.singlePlatformImage(ctx, i.content, tagsByDigest[best.RealTarget.Digest], best)

diff --git a/daemon/containerd/image_list_test.go b/daemon/containerd/image_list_test.go
@@ -7,6 +7,7 @@ import (
 	"math/rand"
 	"os"
 	"path/filepath"
+	"slices"
 	"sort"
 	"strconv"
 	"testing"
@@ -206,6 +207,9 @@ func TestImageList(t *testing.T) {
 	configTarget, err := specialimage.ConfigTarget(blobsDir)
 	assert.NilError(t, err)
 
+	textplain, err := specialimage.TextPlain(blobsDir)
+	assert.NilError(t, err)
+
 	cs := &blobsDirContentStore{blobs: filepath.Join(blobsDir, "blobs/sha256")}
 
 	for _, tc := range []struct {
@@ -276,17 +280,34 @@ func TestImageList(t *testing.T) {
 			name:   "three images, one is an empty index",
 			images: imagesFromIndex(multilayer, emptyIndex, twoplatform),
 			check: func(t *testing.T, all []*imagetypes.Summary) {
-				assert.Check(t, is.Len(all, 2))
+				assert.Check(t, is.Len(all, 3))
 			},
 		},
 		{
-			// Make sure an invalid image target doesn't break the whole operation
 			name:   "one good image, second has config as a target",
 			images: imagesFromIndex(multilayer, configTarget),
 			check: func(t *testing.T, all []*imagetypes.Summary) {
-				assert.Check(t, is.Len(all, 1))
+				assert.Check(t, is.Len(all, 2))
+
+				sort.Slice(all, func(i, j int) bool {
+					return slices.Contains(all[i].RepoTags, "multilayer:latest")
+				})
 
 				assert.Check(t, is.Equal(all[0].ID, multilayer.Manifests[0].Digest.String()))
+				assert.Check(t, is.Len(all[0].Manifests, 1))
+
+				assert.Check(t, is.Equal(all[1].ID, configTarget.Manifests[0].Digest.String()))
+				assert.Check(t, is.Len(all[1].Manifests, 0))
+			},
+		},
+		{
+			name:   "a non-container image manifest",
+			images: imagesFromIndex(textplain),
+			check: func(t *testing.T, all []*imagetypes.Summary) {
+				assert.Check(t, is.Len(all, 1))
+				assert.Check(t, is.Equal(all[0].ID, textplain.Manifests[0].Digest.String()))
+
+				assert.Assert(t, is.Len(all[0].Manifests, 0))
 			},
 		},
 	} {

diff --git a/internal/testutils/specialimage/textplain.go b/internal/testutils/specialimage/textplain.go
@@ -0,0 +1,39 @@
+package specialimage
+
+import (
+	"strings"
+
+	"github.com/distribution/reference"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+// TextPlain creates an non-container image that only contains a text/plain blob.
+func TextPlain(dir string) (*ocispec.Index, error) {
+	ref, err := reference.ParseNormalizedNamed("tianon/test:text-plain")
+	if err != nil {
+		return nil, err
+	}
+
+	emptyJsonDesc, err := writeBlob(dir, "text/plain", strings.NewReader("{}"))
+	if err != nil {
+		return nil, err
+	}
+
+	configDesc := emptyJsonDesc
+	configDesc.MediaType = "application/vnd.oci.empty.v1+json"
+
+	desc, err := writeJsonBlob(dir, ocispec.MediaTypeImageManifest, ocispec.Manifest{
+		Config: configDesc,
+		Layers: []ocispec.Descriptor{
+			emptyJsonDesc,
+		},
+	})
+	if err != nil {
+		return nil, err
+	}
+	desc.Annotations = map[string]string{
+		"io.containerd.image.name": ref.String(),
+	}
+
+	return ociImage(dir, nil, desc)
+}