From 5e42d050a7e44af75601b06f9f19b12a07a6809c Mon Sep 17 00:00:00 2001
From: Jameel Al-Aziz <jameel@bastion.io>
Date: Tue, 18 Jun 2024 21:40:37 -0700
Subject: [PATCH 1/2] Improve support for third-party registry images

Update `ReferenceExpand` to support image references from remote
registries. This fixes local image lookup and pulling with newer
versions of Docker.

fixes #4045

Signed-off-by: Jameel Al-Aziz <jameel@bastion.io>
---
 src/cmd/linuxkit/util/reference.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/cmd/linuxkit/util/reference.go b/src/cmd/linuxkit/util/reference.go
index 7ed89c349..04139b54a 100644
--- a/src/cmd/linuxkit/util/reference.go
+++ b/src/cmd/linuxkit/util/reference.go
@@ -32,7 +32,12 @@ func ReferenceExpand(ref string, options ...ReferenceOption) string {
 	case 1:
 		ret = "docker.io/library/" + ref
 	case 2:
-		ret = "docker.io/" + ref
+		// If the first part is not a domain, assume it is a DockerHub user/org.
+		// This logic is copied from moby:
+		// https://github.com/moby/moby/blob/e7347f8a8c2fd3d2abd34b638d6fc8c18b0278d1/registry/search.go#L148C29-L149C71
+		if !strings.Contains(parts[0], ".") && !strings.Contains(parts[0], ":") && parts[0] != "localhost" {
+			ret = "docker.io/" + ref
+		}
 	}
 
 	if opts.withTag && !strings.Contains(ret, ":") {

From 21e9f0fa1c1a809ea1a364302ab6a46fcc964c7a Mon Sep 17 00:00:00 2001
From: Jameel Al-Aziz <jameel@bastion.io>
Date: Sat, 22 Jun 2024 01:58:37 -0400
Subject: [PATCH 2/2] add tests

Signed-off-by: Jameel Al-Aziz <jameel@bastion.io>
---
 src/cmd/linuxkit/util/reference_test.go | 59 +++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 src/cmd/linuxkit/util/reference_test.go

diff --git a/src/cmd/linuxkit/util/reference_test.go b/src/cmd/linuxkit/util/reference_test.go
new file mode 100644
index 000000000..b96232e49
--- /dev/null
+++ b/src/cmd/linuxkit/util/reference_test.go
@@ -0,0 +1,59 @@
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReferenceExpand(t *testing.T) {
+	tests := []struct {
+		name    string
+		ref     string
+		options []ReferenceOption
+		want    string
+	}{
+		{
+			"basic image name should expand to docker.io/library image",
+			"redis",
+			nil,
+			"docker.io/library/redis",
+		},
+		{
+			"image name with user/org should expand to docker.io image",
+			"foo/bar",
+			nil,
+			"docker.io/foo/bar",
+		},
+		{
+			"custom registry image name should not expand",
+			"myregistry.io/foo",
+			nil,
+			"myregistry.io/foo",
+		},
+		{
+			"image name with more than three parts should not expand",
+			"foo/bar/baz",
+			nil,
+			"foo/bar/baz",
+		},
+		{
+			"with tag should add latest if image does not have tag",
+			"redis",
+			[]ReferenceOption{ReferenceWithTag()},
+			"docker.io/library/redis:latest",
+		},
+		{
+			"with tag should not add latest if image already has tag",
+			"redis:alpine",
+			[]ReferenceOption{ReferenceWithTag()},
+			"docker.io/library/redis:alpine",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ReferenceExpand(tt.ref, tt.options...)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}