Allow the usage of JSON for Elixir 1.18+

[altjohndev]

Sadly, the JSON kernel module does not provide the encode/1 function, which impacts the usage of this library.

In order to match the kernel implementation, this PR changes the interface from decode/1 and encode/1 to decode!/1 and encode!/1.

This PR does not change the default library (keeping it as Jason).

It will use JSON for tests if the Elixir version is 1.18+. The CI tests both libraries.

[whatyouhide]

I’m thinking maybe a better approach for this would be:

1. Introduce a private module, Sentry.JSON, which would act as a temporary middleman (until we will depend on Elixir 1.18+).
2. Check the Elixir version when compiling Sentry and
   1. Use JSON if on Elixir 1.18+, no configuration (after all, we'll eventually drop :json_library now that JSON is in stdlib) + warn if :json_library is configured. This also means we don't need to switch to encode! and decode!, we know which lib we're using.
   2. Use the configured :json_library if on earlier versions.

Thoughts?

[altjohndev]

Hi @whatyouhide , applied the suggested changes.

Use JSON if on Elixir 1.18+, no configuration (after all, we'll eventually drop :json_library now that JSON is in stdlib) + warn if :json_library is configured. This also means we don't need to switch to encode! and decode!, we know which lib we're using.

It would be wise to still let developers define custom libraries during this transitioning period.

[whatyouhide]

It would be wise to still let developers define custom libraries during this transitioning period.

Why? I can only think of custom protocols and stuff like that, but maybe that's already enough.

[altjohndev]

Why? I can only think of custom protocols and stuff like that, but maybe that's already enough.

Just like this library was not ready to use the JSON module, many other libraries and services will require adjustments.

For example, Some services/libraries require a transition for structs that derive from Jason (or another encoder) to derive to JSON instead.

[whatyouhide]

many other libraries and services will require adjustments

True, but using JSON alongside other JSON library would totally be fine. Either way, I get the point: let's keep the configuration option then, but change the default to JSON. This is a bit of a breaking change but one we can deal with IMO, we just advise people to explicitly set the :json_library option if they're on 1.18 but don't want to use JSON.

[altjohndev]

Thank you for the advice. 🙇

Let me know if I need to change or improve something.

[whatyouhide]

Closing in favor of #845.