libimage: enforce "latest" tag when looking up images

Make sure to enforce the "latest" tag when looking up images in the
local storage.  Also make sure that digested short-names are subject
to the extended digest lookups.

Context: containers/podman/issues/11964
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

libimage/pull_test.go

@@ -85,35 +85,41 @@ func TestPullPlatforms(t *testing.T) {
 	localArch := goruntime.GOARCH
 	localOS := goruntime.GOOS
 
-	pulledImages, err := runtime.Pull(ctx, "busybox", config.PullPolicyAlways, pullOptions)
+	withTag := "busybpx:musl"
+
+	pulledImages, err := runtime.Pull(ctx, withTag, config.PullPolicyAlways, pullOptions)
 	require.NoError(t, err, "pull busybox")
 	require.Len(t, pulledImages, 1)
 
-	image, _, err := runtime.LookupImage("busybox", nil)
+	image, _, err := runtime.LookupImage(withTag, nil)
 	require.NoError(t, err, "lookup busybox")
 	require.NotNil(t, image, "lookup busybox")
 
-	image, _, err = runtime.LookupImage("busybox", &LookupImageOptions{Architecture: localArch})
+	_, _, err := runtime.LookupImage("busybox", nil)
+	require.Error(t, err, "untagged image resolves to non-existent :latest")
+
+
+	image, _, err = runtime.LookupImage(withTag, &LookupImageOptions{Architecture: localArch})
 	require.NoError(t, err, "lookup busybox - by local arch")
 	require.NotNil(t, image, "lookup busybox - by local arch")
 
-	image, _, err = runtime.LookupImage("busybox", &LookupImageOptions{OS: localOS})
+	image, _, err = runtime.LookupImage(withTag, &LookupImageOptions{OS: localOS})
 	require.NoError(t, err, "lookup busybox - by local arch")
 	require.NotNil(t, image, "lookup busybox - by local arch")
 
-	_, _, err = runtime.LookupImage("busybox", &LookupImageOptions{Architecture: "bogus"})
+	_, _, err = runtime.LookupImage(withTag, &LookupImageOptions{Architecture: "bogus"})
 	require.Error(t, err, "lookup busybox - bogus arch")
 
-	_, _, err = runtime.LookupImage("busybox", &LookupImageOptions{OS: "bogus"})
+	_, _, err = runtime.LookupImage(withTag, &LookupImageOptions{OS: "bogus"})
 	require.Error(t, err, "lookup busybox - bogus OS")
 
 	pullOptions.Architecture = "arm"
-	pulledImages, err = runtime.Pull(ctx, "busybox", config.PullPolicyAlways, pullOptions)
+	pulledImages, err = runtime.Pull(ctx, withTag, config.PullPolicyAlways, pullOptions)
 	require.NoError(t, err, "pull busybox - arm")
 	require.Len(t, pulledImages, 1)
 	pullOptions.Architecture = ""
 
-	image, _, err = runtime.LookupImage("busybox", &LookupImageOptions{Architecture: "arm"})
+	image, _, err = runtime.LookupImage(withTag, &LookupImageOptions{Architecture: "arm"})
 	require.NoError(t, err, "lookup busybox - by arm")
 	require.NotNil(t, image, "lookup busybox - by local arch")
 }

libimage/runtime.go

@@ -389,15 +389,16 @@ func (r *Runtime) lookupImageInDigestsAndRepoTags(name string, options *LookupIm
 		return nil, "", err
 	}
 
-	if !shortnames.IsShortName(name) {
-		named, err := reference.ParseNormalizedNamed(name)
-		if err != nil {
-			return nil, "", err
-		}
-		digested, hasDigest := named.(reference.Digested)
-		if !hasDigest {
+	named, err := reference.ParseNormalizedNamed(name)
+	if err != nil {
+		return nil, "", err
+	}
+	digested, hasDigest := named.(reference.Digested)
+	if !hasDigest {
+		if !shortnames.IsShortName(name) {
 			return nil, "", errors.Wrap(storage.ErrImageUnknown, name)
 		}
+	} else {
 
 		logrus.Debug("Looking for image with matching recorded digests")
 		digest := digested.Digest()
@@ -408,17 +409,15 @@ func (r *Runtime) lookupImageInDigestsAndRepoTags(name string, options *LookupIm
 				}
 			}
 		}
-
-		return nil, "", errors.Wrap(storage.ErrImageUnknown, name)
 	}
 
 	// Podman compat: if we're looking for a short name but couldn't
-	// resolve it via the registries.conf dance, we need to look at *all*
-	// images and check if the name we're looking for matches a repo tag.
-	// Split the name into a repo/tag pair
+	// resolve until this point, we need to look at *all* images and check
+	// if the name we're looking for matches a repo tag.  Split the name
+	// into a repo/tag pair
 	split := strings.SplitN(name, ":", 2)
 	repo := split[0]
-	tag := ""
+	tag := "latest" // See containers/podman/issues/11964.
 	if len(split) == 2 {
 		tag = split[1]
 	}