fix(args): none arg set slice ptr to an empty slice (#2752)

Author: Codelax

internal/args/unmarshal.go

@@ -240,8 +240,11 @@ func set(dest reflect.Value, argNameWords []string, value string) error {
 		// - dest is a pointer to a slice
 		// - there is no more argNameWords left
 		// - value == none
-		// we let the slice empty and return
+		// slice ptr was allocated
+		// we allocate the empty slice and return
 		if dest.Elem().Kind() == reflect.Slice && len(argNameWords) == 0 && value == emptySliceValue {
+			sliceDest := dest.Elem()
+			sliceDest.Set(reflect.MakeSlice(sliceDest.Type(), 0, 0))
 			return nil
 		}
 

internal/args/unmarshal_test.go

@@ -202,7 +202,7 @@ func TestUnmarshalStruct(t *testing.T) {
 		},
 		expected: &Slice{
 			Strings:    []string(nil),
-			SlicePtr:   scw.StringsPtr(nil),
+			SlicePtr:   scw.StringsPtr([]string{}),
 			StringsPtr: []*string(nil),
 		},
 	}))