pub fn deserialize_optional_field<'de, T, D>(
deserializer: D,
) -> Result<Option<Option<T>>, D::Error>where
D: Deserializer<'de>,
T: Deserialize<'de>,Expand description
Hack to deserialize an Optional Option<T>
This is to differentiate between “missing” values and null values.
For example in json {"v": null} and {} are different things, in the first one, v is null, but in the second, v is undefined.