Merge pull request #1900 from thaJeztah/improve-invalid-reference-errormessage

Improve "invalid reference" error message

reference/reference.go

@@ -24,6 +24,7 @@ package reference
 import (
 	"errors"
 	"fmt"
+	"strings"
 
 	"github.com/docker/distribution/digest"
 )
@@ -43,6 +44,9 @@ var (
 	// ErrDigestInvalidFormat represents an error while trying to parse a string as a tag.
 	ErrDigestInvalidFormat = errors.New("invalid digest format")
 
+	// ErrNameContainsUppercase is returned for invalid repository names that contain uppercase characters.
+	ErrNameContainsUppercase = errors.New("repository name must be lowercase")
+
 	// ErrNameEmpty is returned for empty, invalid repository names.
 	ErrNameEmpty = errors.New("repository name must have at least one component")
 
@@ -149,7 +153,9 @@ func Parse(s string) (Reference, error) {
 		if s == "" {
 			return nil, ErrNameEmpty
 		}
-		// TODO(dmcgowan): Provide more specific and helpful error
+		if ReferenceRegexp.FindStringSubmatch(strings.ToLower(s)) != nil {
+			return nil, ErrNameContainsUppercase
+		}
 		return nil, ErrReferenceInvalidFormat
 	}
 

reference/reference_test.go

@@ -95,6 +95,25 @@ func TestReferenceParse(t *testing.T) {
 			input: "validname@invaliddigest:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
 			err:   digest.ErrDigestUnsupported,
 		},
+		{
+			input: "Uppercase:tag",
+			err:   ErrNameContainsUppercase,
+		},
+		// FIXME "Uppercase" is incorrectly handled as a domain-name here, therefore passes.
+		// See https://github.com/docker/distribution/pull/1778, and https://github.com/docker/docker/pull/20175
+		//{
+		//	input: "Uppercase/lowercase:tag",
+		//	err:   ErrNameContainsUppercase,
+		//},
+		{
+			input: "test:5000/Uppercase/lowercase:tag",
+			err:   ErrNameContainsUppercase,
+		},
+		{
+			input:      "lowercase:Uppercase",
+			repository: "lowercase",
+			tag:        "Uppercase",
+		},
 		{
 			input: strings.Repeat("a/", 128) + "a:tag",
 			err:   ErrNameTooLong,