[CLI] Fix parsing empty string within arguments

Fixes https://github.com/github/hub/issues/2036

utils/args_parser.go

@@ -95,7 +95,7 @@ func (p *ArgsParser) Parse(args []string) ([]string, error) {
 	for i = 0; i < len(args); i++ {
 		arg = args[i]
 
-		if p.HasTerminated || arg == "-" {
+		if p.HasTerminated || len(arg) == 0 || arg == "-" {
 		} else if arg == "--" {
 			if !p.HasTerminated {
 				p.HasTerminated = true

utils/args_parser_test.go

@@ -70,6 +70,14 @@ func TestArgsParser_UnknownFlag(t *testing.T) {
 	equal(t, true, p.Bool("--yes"))
 }
 
+func TestArgsParser_BlankArgs(t *testing.T) {
+	p := NewArgsParser()
+	rest, err := p.Parse([]string{"", ""})
+	equal(t, nil, err)
+	equal(t, []string{"", ""}, rest)
+	equal(t, []int{0, 1}, p.PositionalIndices)
+}
+
 func TestArgsParser_Values(t *testing.T) {
 	p := NewArgsParser()
 	p.RegisterValue("--origin", "-o")