Query caching broken with some custom scalars and JIT

[lsanwick]

Query caching broken with some custom scalars and JIT

[mcollina]

Thanks for reporting!

Can you provide steps to reproduce? We often need a reproducible example, e.g. some code that allows someone else to recreate your problem by just copying and pasting it. If it involves more than a couple of different file, create a new repository on GitHub and add a link to that.

[lsanwick]

Okay, I've created a repoduction repo here: https://github.com/lsanwick/custom-scalar-caching-example

It appears that the issue appears with this configuration:

  await fastify.register(mercurius, {
    schema,
    resolvers,
    jit: true,
    graphiql: true,
  });

If you disable JIT, or disable caching while keeping JIT enabled, I don't see the issue.

  jit: true,
  cache: false,

[lsanwick]

@mcollina Is that sufficient to work off of, or do you need anything else?

[mcollina]

I currently do not have much time to look into it. This looks like an issue inside graphql-jit.

I never experience this exact issue so maybe there is something that intersects between that and luxon.