Update Parse implementation to match the comments - particularly that Parse acts differently than ParseRelative

ociref/reference.go

@@ -164,7 +164,7 @@ func IsValidDigest(d string) bool {
 // Unlike "docker pull" however, there is no default registry: when
 // presented with a bare repository name, Parse will return an error.
 func Parse(refStr string) (Reference, error) {
-	ref, err := ParseRelative(refStr)
+	ref, err := parse(refStr)
 	if err != nil {
 		return Reference{}, err
 	}
@@ -179,9 +179,28 @@ func Parse(refStr string) (Reference, error) {
 //
 // It is represented in string form as [HOST[:PORT]/]NAME[:TAG|@DIGEST]
 // form: the same syntax accepted by "docker pull".
-// Unlike "docker pull" however, there is no default registry: when
-// presented with a bare repository name, the Host field will be empty.
+// Like "docker pull", references without a host default to Docker Hub,
+// and single-component Docker Hub repository names default to the "library"
+// namespace.
 func ParseRelative(refStr string) (Reference, error) {
+	ref, err := parse(refStr)
+	if err != nil {
+		return Reference{}, err
+	}
+	// Normalize Docker Hub registry hosts, also default to Docker if none is provided
+	if _, ok := ocidocker.DockerHubHosts[ref.Host]; ok || ref.Host == "" {
+		ref.Host = "docker.io"
+	}
+	if ref.Host == "docker.io" && !strings.Contains(ref.Repository, "/") {
+		ref.Repository = "library/" + ref.Repository
+	}
+	if len(ref.Repository) > 255 {
+		return Reference{}, fmt.Errorf("repository name too long")
+	}
+	return ref, nil
+}
+
+func parse(refStr string) (Reference, error) {
 	m := referencePat().FindStringSubmatch(refStr)
 	if m == nil {
 		return Reference{}, fmt.Errorf("invalid reference syntax (%q)", refStr)
@@ -201,13 +220,6 @@ func ParseRelative(refStr string) (Reference, error) {
 			return Reference{}, fmt.Errorf("invalid digest %q: %v", ref.Digest, err)
 		}
 	}
-	// Normalize Docker Hub registry hosts, also default to Docker if none is provided
-	if _, ok := ocidocker.DockerHubHosts[ref.Host]; ok || ref.Host == "" {
-		ref.Host = "docker.io"
-	}
-	if ref.Host == "docker.io" && !strings.Contains(ref.Repository, "/") {
-		ref.Repository = "library/" + ref.Repository
-	}
 	if len(ref.Repository) > 255 {
 		return Reference{}, fmt.Errorf("repository name too long")
 	}

ociref/reference_test.go

@@ -400,15 +400,60 @@ func TestParseReference(t *testing.T) {
 			require.NoError(t, err)
 			assert.Equal(t, test.wantRef, ref)
 			//assert.Equal(t, test.input, ref.String())
-			if test.wantRef.Host != "" {
-				ref1, err := Parse(test.input)
-				require.NoError(t, err)
-				assert.Equal(t, test.wantRef, ref1)
-			} else {
-				_, err := Parse(test.input)
+		})
+	}
+}
+
+func TestParse(t *testing.T) {
+	tests := []struct {
+		input   string
+		wantErr string
+		wantRef Reference
+	}{{
+		input: "test.com/repo:tag",
+		wantRef: Reference{
+			Host:       "test.com",
+			Repository: "repo",
+			Tag:        "tag",
+		},
+	}, {
+		input: "test:5000/repo",
+		wantRef: Reference{
+			Host:       "test:5000",
+			Repository: "repo",
+		},
+	}, {
+		input: "docker.io/ubuntu",
+		wantRef: Reference{
+			Host:       "docker.io",
+			Repository: "ubuntu",
+		},
+	}, {
+		input: "index.docker.io/foo",
+		wantRef: Reference{
+			Host:       "index.docker.io",
+			Repository: "foo",
+		},
+	}, {
+		input:   "test_com",
+		wantErr: `reference does not contain host name`,
+	}, {
+		input:   "rocket.chat",
+		wantErr: `reference does not contain host name`,
+	}, {
+		input:   "test.com:5000",
+		wantErr: `reference does not contain host name`,
+	}}
+	for _, test := range tests {
+		t.Run(test.input, func(t *testing.T) {
+			ref, err := Parse(test.input)
+			if test.wantErr != "" {
 				require.Error(t, err)
-				require.Regexp(t, `reference does not contain host name`, err.Error())
+				require.Regexp(t, test.wantErr, err.Error())
+				return
 			}
+			require.NoError(t, err)
+			assert.Equal(t, test.wantRef, ref)
 		})
 	}
 }