conf: allow to set empty slices with empty env variables

internal/conf/env.go

@@ -135,8 +135,12 @@ func loadEnvInternal(env map[string]string, prefix string, rv reflect.Value) err
 	case reflect.Slice:
 		if rt.Elem() == reflect.TypeOf("") {
 			if ev, ok := env[prefix]; ok {
+				if ev == "" {
+					rv.Set(reflect.ValueOf([]string{}))
+				} else {
 					rv.Set(reflect.ValueOf(strings.Split(ev, ",")))
 				}
+			}
 			return nil
 		}
 	}

internal/conf/env_test.go

@@ -25,6 +25,7 @@ type testStruct struct {
 	MyDuration   StringDuration
 	MyMap        map[string]*mapEntry
 	MySlice      []string
+	MySliceEmpty []string
 }
 
 func TestEnvironment(t *testing.T) {
@@ -55,6 +56,9 @@ func TestEnvironment(t *testing.T) {
 	os.Setenv("MYPREFIX_MYSLICE", "val1,val2")
 	defer os.Unsetenv("MYPREFIX_MYSLICE")
 
+	os.Setenv("MYPREFIX_MYSLICEEMPTY", "")
+	defer os.Unsetenv("MYPREFIX_MYSLICEEMPTY")
+
 	var s testStruct
 	err := loadFromEnvironment("MYPREFIX", &s)
 	require.NoError(t, err)
@@ -74,4 +78,5 @@ func TestEnvironment(t *testing.T) {
 	require.Equal(t, 456, v.MyStruct.MyParam)
 
 	require.Equal(t, []string{"val1", "val2"}, s.MySlice)
+	require.Equal(t, []string{}, s.MySliceEmpty)
 }