Type id not provided on `Double.NaN`, `Infinity` with `@JsonTypeInfo`

[C-B-B]

When using polymorphic serialisation with @JsonTypeInfo, e.g. on a Collection of Objects, the type information is sent with the values to ensure correct deserialisation. Doubles (and others like Strings) don't get their types included given they are considered the default deserialisation type. This causes problems for Double.NaN, Double.POSITIVE_INFINITY and Double.NEGATIVE_INFINITY as they get deserialised into strings rather than Double.

Would it make sense to include the type for these three Double values to ensure they can also be correctly deserialised (I tested that the deserialisation works correctly if the type is included in the data)?

(Using 2.9.8)

Thanks!
CBB

[cowtowncoder]

Interesting edge case. Yes, that would indeed make sense.
Thank you for reporting the issue.

My main concern (without looking at code yet) is whether output as String is handled by serializer (if so, easy), or low-level JsonGenerator -- latter case would be difficult to handle cleanly wrt separation of responsibilities.

[antoinetran]

Hi @cowtowncoder , is-it possible to have the same fix related to Float? Or is-it already working? Thank you!

[antoinetran]

Oh, I can see that this is already fixed for float, I believe.
I use

	<dependency>
		<groupId>com.fasterxml.jackson.core</groupId>
		<artifactId>jackson-databind</artifactId>
		<version>2.9.8</version>
	</dependency>

and Float.NaN gets serialized as:
["[[F",[["[F",["NaN"
and gets deserialized as Float.NaN, so this is good. I should try with Double later.