Flaw in algorithm?

[jvican]

I'm trying to generate picklers and unpicklers for Spores. One problem I'm hitting is that despite having static picklers/unpicklers for a given Spore, scala-pickling generates their own brand-new picklers/unpicklers. For instance, let's say we have this:

case class B[S](value: S)
val s: Spore[T, B[S]] = ???
implicitly[Pickler[Spore[T, B[S]]]
implicitly[Unpickler[Spore[T, B[S]]]

Types T and S are concrete in the call site.

The aforementioned problem appears when we don't have a Pickler/Unpickler for B. Therefore, scala-pickling will infer that there's no Pickler/Unpickler for the spore type and generate them as well.

In my opinion, a fix for this problem is to change how the algorithm proceeds. If there's no Pickler/Unpickler for B, we generate them and then check if there's now a Pickler/Unpickler that matches Spore[T,S] and compose them.

If my previous analysis is not correct, this may be a problem caused by a bad registration of Picklers and Unpicklers. I'm using HybridRuntime. Also note that I am not using staticOnly.

This only affects scala pickling v0.11.x.

[jvican]

Just want to clarify that the Picklers/Unpicklers of Spore are not generated in the call site. I propagate the Picklers/Unpicklers of S through my API and then at some point invoke those implicitly. If before those statements I place implicitly[B[S]], the problem disappears because scala pickling detects a type R (B[S]) which is able to fit in Spore[T, R].

[jsuereth]

Can you place a small reproducable example? I'm having trouble seeing this myself, and I'd like to try to fix it.

Note: one of my larger TODO items is to clean up how dependent-picklers are looked up in teh macros. Right now it's a recursive chain of macro-invocation for implciitly finding picklers. may remain that way, but be less flaky in the future...