Draft: Config support

[pjfanning]

No description provided.

[cowtowncoder]

In general, builder-style configuration is being added to most Jackson modules so that might make sense here too, even if providing full Config objects?

[pjfanning]

@cowtowncoder my preference is still to add a jackson-databind DeserializationFeature and to uptake it in jackson-module-scala. This is just an alternative approach if we decide to keep the solution entirely in jackson-module-scala.

The typesafe config is a commonly used way to configure scala libs and helps to avoid adding new APIs for setting config.

[cowtowncoder]

@pjfanning I know typesafe config is widely used it's just that my experience suggests that usually such libraries/frameworks work better for main level applications/services/clients and can be less optimal (when doing automatic classpath scanning etc) for embedded components, which is a common use case for Jackson.
Challenges usually come from cases where Jackson is used by multiple unrelated subsystems (or app and one of its dependencies). Because of this I prefer a little bit of explicitness -- even if only requiring call like "just load typesafe config (from specific section)".

But that is just a suggestion; if you think configuration as specified makes sense that is fine.

Ditto wrt Jackson features.

[pjfanning]

@cowtowncoder this config solution is not a solution I like but adding the current jackson-module-scala code was written in a way that makes configuring it using a Module Builder very hard without breaking binary compatibility. See https://github.com/FasterXML/jackson-module-scala/blob/master/src/main/scala/com/fasterxml/jackson/module/scala/DefaultScalaModule.scala and the way the submodules are traits, meaning I can't pass stateful class instances into them.

A Module Builder would be a nice feature for jackson-module-scala v3 but I think it would be easy in v2. And so far, we have just a small number of v2 users asking for 1 config option.

My preferred option for jackson v2 is FasterXML/jackson-databind#3181 or a variant of it - that would would allow me to get the config from the existing jackson-databind classes.

[cowtowncoder]

@pjfanning Ok I don't have any big problems with another feature to add and it is a fair point that there's just this one request for now.
I was guessing that "fake" Builder which other modules use might work, but it sounds like the structuring of Scala module (much more based on sort of loose composition if I understand it?) makes that impractical for 2.x.
Thank you for explaining the situation.

[pjfanning]

Using a MapperFeature instead