fix support for empty git ref with subdir

Signed-off-by: CrazyMax <[email protected]>

Author: crazy-max

util/gitutil/git_ref.go

@@ -73,22 +73,12 @@ func ParseGitRef(ref string) (*GitRef, error) {
 		}
 	}
 
-	refSplitBySharp := strings.SplitN(ref, "#", 2)
-	res.Remote = refSplitBySharp[0]
+	var fragment string
+	res.Remote, fragment, _ = strings.Cut(ref, "#")
 	if len(res.Remote) == 0 {
 		return res, errdefs.ErrInvalidArgument
 	}
-
-	if len(refSplitBySharp) > 1 {
-		refSplitBySharpSplitByColon := strings.SplitN(refSplitBySharp[1], ":", 2)
-		res.Commit = refSplitBySharpSplitByColon[0]
-		if len(res.Commit) == 0 {
-			return res, errdefs.ErrInvalidArgument
-		}
-		if len(refSplitBySharpSplitByColon) > 1 {
-			res.SubDir = refSplitBySharpSplitByColon[1]
-		}
-	}
+	res.Commit, res.SubDir, _ = strings.Cut(fragment, ":")
 	repoSplitBySlash := strings.Split(res.Remote, "/")
 	res.ShortName = strings.TrimSuffix(repoSplitBySlash[len(repoSplitBySlash)-1], ".git")
 	return res, nil

util/gitutil/git_ref_test.go

@@ -110,6 +110,14 @@ func TestParseGitRef(t *testing.T) {
 			ref:      "http://github.com/docker/docker.git:#branch",
 			expected: nil,
 		},
+		{
+			ref: "https://github.com/docker/docker.git#:myfolder",
+			expected: &GitRef{
+				Remote:    "https://github.com/docker/docker.git",
+				ShortName: "docker",
+				SubDir:    "myfolder",
+			},
+		},
 	}
 	for _, tt := range cases {
 		tt := tt