JacksonJsonIO may throw exception when trying to read a number

[Azquelt]

JacksonJsonIO.getJsonBigDecimal does not check that the node contains a number before trying to parse it as a big decimal.

This results in a NumberFormatException rather than a null as the Javadoc would suggest.

Admittedly, the Javadoc was written after the implementation, so arguably it's the Javadoc that's wrong here, but having this method return a null would be consistent with the other methods in this class.

This can result in throwing an exception when parsing an OpenAPI 3.0 schema rather than ignoring the invalid field.

Ideally we should unit test the JsonIO implementations. There may be other similar bugs.

[MikeEdgar]

+1

Currently it supports both text and numeric JSON values. I wonder if that it correct or whether it should be limited to only numeric values. That can easily be tested with JsonNode#isNumber together with JsonNode#decimalValue, but allowing text would require a bit more involved check.