pub fn optional_additional_params<'de, D>(
deserializer: D,
) -> Result<Option<AdditionalParams>, D::Error>where
D: Deserializer<'de>,Expand description
Serde route for Option<AdditionalParams> fields: an explicit null or
{} decodes as None, exactly like an absent field — a mechanically
migrated block that wrote "additional_params": {} classifies identically
to one that omitted the key. Any other non-object value is a loud decode
error: extras are a keyed namespace (every producer stores an object,
every extractor gets a key), so a mis-migrated [] or bare string is
malformed data, not a phantom annotation no reader can see.