Custom error cloning to fix node v21 issue

[kanongil]

This PR fixes a Hoek.clone(err) issue introduced in node v21.

The problem

Node 21 updates the V8 engine to 11.8, which includes a patch from v11.5.1 that changes how the Error.stack property works.

With this patch, a copied err.stack descriptor will no longer return the stack of the source error, but always return undefined. This breaks Boom, where it relies on clone() to fully work.

This manifestation of this issue was reported on discord.

The solution

The only way to copy a working stack descriptor in node 21, is to used the structuredClone() method. This is a platform method that uses an algorithm from the HTML spec to create a "clone". Only the "name", "message", "cause", and "stack" properties are transferred, and the prototype is set to a standard Error. See the serialization algorithm step 17 which deals with [[ErrorData]] objects.

I use structuredClone() to create the base object, and then pass it through the standard recursive object cloner to clone all properties except the stack property. This preserves the existing behaviour, including for weird corner cases.

This PR will only work with node >= v17.0.0, which is when structuredClone() was added. Given that every node release <18 is no longer supported, I don't want to spend energy fixing this, and expect that this fix can be part of a new breaking change release. Or is the current release expected to support node v21?

[Marsup]

Should we then do node version detection? I don't think hapi 22 is anywhere near.

[Nargonath]

I agree with @Marsup, AFAIK hapi@22 is not going to see the light soon. If we want to deploy this fix faster, keeping a retro-compatibility might be best especially since this fix is only needed for >= node@21 AFAIU.

[kanongil]

It's simple enough to support both with a few if (typeof structuredClone === 'function') { … }, falling back to the current handling. It gets a bit more complicated regarding the test code coverage, which can only enter one of the branches.

[kanongil]

IMO, if no significant breaking changes to functionality are pending, hapi and its dependencies should do a version bump to deprecate node v14 and v16 and support v20. It would be nice to finally merge hapijs/hapi#4433.

FYI, the hapi test suite fails some tests on node v20 (at least on macOS).