Add JsonNodeFeature.FAIL_ON_NAN_TO_BIG_DECIMAL_COERCION option to fail on attempting to coerce NaN into BigDecimal

[cowtowncoder]

Describe your Issue

(follow up to #1770)

So, we should not (by default) coerce "NaN"s (infinity, NaN) for JsonNode as is done with #1770 fixed.
There should probably be a JsonNodeFeature to allow such coercion, however.

[JooHyukKim]

+1 Adding an option for backward compatibility and moving-forward to 3.0.

I am guessing that...

• Considering backward-compatibility, allow coercion by default in Jackson 2.x
• Disallow by default in Jackson 3.x

Then users who want to keep allowing by explicitly enabling the option

[cowtowncoder]

@JooHyukKim Yes. For 3.0 probably want to split JsonNode specific configuration into JsonNodeFeature, and leave/refactor other setting to only affect Object / Number case.

[pjfanning]

Just my opinion - but I think we don't need another config. Support for NaN/Infinity are not default in Jackson. You need to enable JsonReadFeature.ALLOW_NON_NUMERIC_NUMBERS (on the JsonFactory).

So users who want BigDecimals should not enable JsonReadFeature.ALLOW_NON_NUMERIC_NUMBERS.

[cowtowncoder]

This is bit different @pjfanning -- it has to do with what to do when NaNs are accepted from input but there is need to coerce floating-point numbers to BigDecimal.
This could work in at least 2 ways:

1. Quietly use DoubleNode instead of BigDecimalNode (i.e. prevent impossible coercion)
2. Fail on encountering case that cannot be supported

while we could technically just select one of these cases always, it seems like a thing that users might want to select differently.

[cowtowncoder]

Ok, after re-reading relevant issues, refreshing my memory, I concur with @pjfanning that isNaN() is (in combination with getNumberType()) unreliable.

I filed FasterXML/jackson-core#1149 for some additional work; and there is FasterXML/jackson-core#1137 already.
With those, I think we can solve the issue.

I also think that with changes, we probably want to rename this feature. Why? Because:

1. There is already case of explicit NaN coming optionally from input (NaN, +/-INFINITY) BUT
2. There is ALSO possibility of +INFINITY/-INFINITY from "too big/small Double value" -- so question is, whether to automatically Coerce (Promote?) Double into BigDecimal to allow value to be represented.

Or maybe we want 2 features? This one for NaN -> Double override (even if otherwise prefer BigDecimal), and then new one for Too Big/Small Double -> BigDecimal promotion.