Fix error for list value - returns one empty item for a list when dat…

…a is not passed to the command line

args.go

@@ -277,13 +277,15 @@ func (am argMap) posValues() []string {
 }
 
 // The flagValue returns the value for the specified flag by
-// long and/or short name. If the value is not found - returns defValue.
+// long and/or short name with true as second param.
+// Returns defValue with false as second param if the value
+// is not found.
 func (am argMap) flagValue(
 	shortFlag string,
 	longFlag string,
 	defValue string,
 	sepList string,
-) []string {
+) ([]string, bool) {
 	var result []string
 
 	// Join all values from all types of flags (long/short).
@@ -296,7 +298,7 @@ func (am argMap) flagValue(
 
 	// Return default value.
 	if len(tmp) == 0 {
-		return []string{defValue}
+		return []string{defValue}, false
 	}
 
 	// Be sure to set the sequence of values that was in the command line.
@@ -313,5 +315,5 @@ func (am argMap) flagValue(
 		result = append(result, item.value)
 	}
 
-	return result
+	return result, true
 }

args_test.go

@@ -107,7 +107,7 @@ func TestPositional(t *testing.T) {
 		}
 
 		// Check app name.
-		value := am.flagValue("0", "", "", "")
+		value, _ := am.flagValue("0", "", "", "")
 		if r := strings.Join(value, ""); r != tests[0][0] {
 			t.Errorf("%d test, expected %v but %v", i, tests[0][0], r)
 		}
@@ -140,7 +140,7 @@ func TestValue(t *testing.T) {
 			t.Error(err)
 		}
 
-		r := am.flagValue("U", "users", "Jan,Bob", "")
+		r, _ := am.flagValue("U", "users", "Jan,Bob", "")
 		if !reflect.DeepEqual(r, expected) {
 			t.Errorf("expected %v but %v", expected, r)
 		}
@@ -177,7 +177,7 @@ func TestSplit(t *testing.T) {
 			t.Error(err)
 		}
 
-		r := am.flagValue("U", "users", "Jan,Bob,Roy", "")
+		r, _ := am.flagValue("U", "users", "Jan,Bob,Roy", "")
 		if !equal(r, expected) {
 			t.Errorf("test %d, expected %v but %v", i, expected, r)
 		}
@@ -201,7 +201,7 @@ func TestSplitFolding(t *testing.T) {
 			t.Error(err)
 		}
 
-		r := am.flagValue("U", "users", "Jan,Bob,Roy", "")
+		r, _ := am.flagValue("U", "users", "Jan,Bob,Roy", "")
 		if !reflect.DeepEqual(r, expected) {
 			t.Errorf("test %d, expected %v but %v", i, expected, r)
 		}

decode.go

@@ -73,14 +73,14 @@ func unmarshalOpt(obj interface{}, args []string) []error {
 		)
 		arg = strings.Trim(arg, " or/and ")
 
-		value, kind := []string{}, fc.item.Kind()
+		value, kind, ok := []string{}, fc.item.Kind(), false
 		switch f := fc.tagGroup.shortFlag; {
 		case f == "[]":
 			// Get positional arguments.
 			value = am.posValues()
 		default:
 			// Get the values of the argument.
-			value = am.flagValue(
+			value, ok = am.flagValue(
 				fc.tagGroup.shortFlag,
 				fc.tagGroup.longFlag,
 				fc.tagGroup.defValue,
@@ -106,6 +106,14 @@ func unmarshalOpt(obj interface{}, args []string) []error {
 			// If a separator is specified, the elements must be separated.
 			var result []string
 
+			// If the argMap.flagValue hasn't value it's returns
+			// []string{defValue} where defValue can be like "" -
+			// this is not valid for the list because if the command line
+			// argument has no data for the list this list must be empty!
+			if !ok && len(value) == 1 && value[0] == "" {
+				break
+			}
+
 			if sep := fc.tagGroup.sepList; sep != "" {
 				for _, item := range value {
 					tmp := strings.Split(item, sep)
@@ -134,6 +142,14 @@ func unmarshalOpt(obj interface{}, args []string) []error {
 			// If a separator is specified, the elements must be separated.
 			var result []string
 
+			// If the argMap.flagValue hasn't value it's returns
+			// []string{defValue} where defValue can be like "" -
+			// this is not valid for the list because if the command line
+			// argument has no data for the list this list must be empty!
+			if !ok && len(value) == 1 && value[0] == "" {
+				break
+			}
+
 			if sep := fc.tagGroup.sepList; sep != "" {
 				for _, item := range value {
 					tmp := strings.Split(item, sep)

doc.go

@@ -1,7 +1,7 @@
 // Package opt implements methods for manage arguments of the command-line.
 package opt
 
-const version = "1.0.1"
+const version = "1.0.2"
 
 // Version returns the version of the module.
 func Version() string {