Fix bug in parsing domain from repository reference

Signed-off-by: Aviral Takkar <aviral26@users.noreply.github.com>

reference/normalize.go

@@ -90,7 +90,7 @@ func ParseDockerRef(ref string) (Named, error) {
 // needs to be already validated before.
 func splitDockerDomain(name string) (domain, remainder string) {
 	i := strings.IndexRune(name, '/')
-	if i == -1 || (!strings.ContainsAny(name[:i], ".:") && name[:i] != "localhost") {
+	if i == -1 || (!strings.ContainsAny(name[:i], ".:") && name[:i] != "localhost" && strings.ToLower(name[:i]) == name[:i]) {
 		domain, remainder = defaultDomain, name
 	} else {
 		domain, remainder = name[:i], name[i+1:]

reference/normalize_test.go

@@ -28,6 +28,8 @@ func TestValidateReferenceName(t *testing.T) {
 		// when specified with a hostname, it removes the ambiguity from about
 		// whether the value is an identifier or repository name
 		"docker.io/1a3f5e7d9c1b3a5f7e9d1c3b5a7f9e1d3c5b7a9f1e3d5d7c9b1a3f5e7d9c1b3a",
+		"Docker/docker",
+		"DOCKER/docker",
 	}
 	invalidRepoNames := []string{
 		"https://github.com/docker/docker",
@@ -229,6 +231,20 @@ func TestParseRepositoryInfo(t *testing.T) {
 			AmbiguousName: "",
 			Domain:        "docker.io",
 		},
+		{
+			RemoteName:    "bar",
+			FamiliarName:  "Foo/bar",
+			FullName:      "Foo/bar",
+			AmbiguousName: "",
+			Domain:        "Foo",
+		},
+		{
+			RemoteName:    "bar",
+			FamiliarName:  "FOO/bar",
+			FullName:      "FOO/bar",
+			AmbiguousName: "",
+			Domain:        "FOO",
+		},
 	}
 
 	for _, tcase := range tcases {