An exploration of cats.mtl.Stateful tracing #103
Closed
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
rossabaker
commented
Jan 28, 2023
Comment on lines
+52
to
+62
| def stateful[S](a: S): IO[Stateful[IO, S]] = | ||
| IOLocal(a).map { ioLocal => | ||
| new Stateful[IO, S] { | ||
| override def get: IO[S] = | ||
| ioLocal.get | ||
| override def set(s: S): IO[Unit] = | ||
| ioLocal.set(s) | ||
| override def monad: Monad[IO] = | ||
| Monad[IO] | ||
| } | ||
| } |
There was a problem hiding this comment.
I don't know if this is lawful.
| @@ -47,67 +47,68 @@ private[java] object TraceScope { | |||
| case object Noop extends Scope | |||
| } | |||
|
|
|||
| def fromIOLocal[F[_]: LiftIO: Sync]( | |||
| private[java] def fromStateful[F[_]: Sync: Stateful[*[_], Scope]]( | |||
There was a problem hiding this comment.
Unlike Local, it's not as obvious what other instances we're bringing to the table here. StateT over a Concurrent is generally a bad idea. StateT over a MonadError can go up in smoke.
Could something clever be done with a Ref?
Can we interoperate with synchronous Java with a gulp ThreadLocal? Uh... probably not, because we also need a Sync?
Comment on lines
+86
to
+87
| Stateful[F, Scope].get.flatMap(p => | ||
| Stateful[F, Scope].set(scope).as(p) |
There was a problem hiding this comment.
Does this need to be atomic? 🤔
|
I don't think this is going to work without solving the fs2 interruptScope issue, which I don't think is going to work without solving the CE race local state reconciliation issue, which I don't think is going to be solved. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Like #102, but Stateful instead of Local.