support overriding the codePointLimit

[pjfanning]

#337

Work in progress. Will add tests before merging but would like to open a discussion on the APIs.

Another option is to support setting a snakeyaml LoaderOptions instance on YamlFactoryBuilder, so users would have full control. There are other settings in LoaderOptions that might be useful to support. https://www.javadoc.io/doc/org.yaml/snakeyaml/latest/org/yaml/snakeyaml/LoaderOptions.html

[cowtowncoder]

I think that although in many ways it's good to hide details of the underlying implementation, in this case benefits probably outweigh drawbacks.

One particularly compelling reason here is this: as I understand, this new setting is only available in SnakeYAML 1.32. If so, we either have to:

1. Require baseline of SnakeYAML from users. This will almost certainly gain as many bug reports for breakages from users with different version of SnakeYAML in their classpath
2. Add dynamic loading of piece of code that handles with this setting, to only fail if someone tries to set the limit against older SnakeYAML

But if we only expose functionality for interacting with LoaderOptions (when was it added?), we can avoid this problem altogether.

If it wasn't for this compatibility issue, I might suggest doing both (simple int setting and LoaderOptions), but due to it I suggest exposing LoaderOptions. This assumes it was added in a version that is not "too recent" (like, something that was the baseline for... maybe latest Jackson 2.9.x release?).

[pjfanning]

@cowtowncoder I have reworked to this to allow users to set the LoaderOptions instance explicitly

[cowtowncoder]

Looks good, will merge.

One thing that might make sense -- and I can try to add it -- would be an example of how to expand maximum size limit, on YAML module's README.

[cowtowncoder]

@pjfanning Was able to merge to master, but it looks as if snakeyaml-engine did not have equivalent setting: while LoaderOptions became LoadSettings, I did not see an equivalent to "max code points" in latter.

@asomov Do you know if I missed something obvious (setting is maybe somewhere else), or if omission is intentional?

[asomov]

@cowtowncoder it does not have it yet. But it will get it soon

[cowtowncoder]

@asomov Excellent: no super hurry as this only affects Jackson 3.0.0-SNAPSHOT, not yet released. So just let us know when it is added. Thank you!

[asomov]

@cowtowncoder SnakeYAML Engine version 2.5 with the support for codePointLimit is released

[cowtowncoder]

Thank you @asomov ! I enabled test for this in master for JAckson YAML module against snakeyaml-engine too.

/cc @pjfanning