Struggling to upgrade to v0.48

[bhagdave]

Hi All,

Not sure if this is the right place to ask this question but here goes.

I wanted to start playing with libp2p and started with the example at Log Rocket but found the version of libp2p being used was 0.31 so took a copy of the code repo and started to make the required changes to move it to version 0.47. I now have that working here but when I change the libp2p version to 0.48 I hit a problem with one of the elements of the Behaviour struct (which had #[behaviour(ignore)]) not having a From implementation.

The error I am receiving is:-

error[E0277]: the trait bound `StoryBehaviourEvent: From<<tokio::sync::mpsc::UnboundedSender<ListResponse> as NetworkBehaviour>::OutEvent>` is not satisfied
  --> src/main.rs:64:10
   |
64 | #[derive(NetworkBehaviour)]
   |          ^^^^^^^^^^^^^^^^ the trait `From<<tokio::sync::mpsc::UnboundedSender<ListResponse> as NetworkBehaviour>::OutEvent>` is not implemented for `StoryBehaviourEvent`
   |
   = help: the following other types implement trait `From<T>`:
             <StoryBehaviourEvent as From<FloodsubEvent>>
             <StoryBehaviourEvent as From<MdnsEvent>>
   = help: see issue #48214
   = note: this error originates in the derive macro `NetworkBehaviour` (in Nightly builds, run with -Z macro-backtrace for more info)

I have searched through issues and discussions and the nearest issue I can find is the problems related to using Generics in the struct and I don't think that is relevant here.

Can anyone point me in the right direction? Thanks in advance.

[thomaseizinger]

Not sure if this is the right place to ask this question

It is!

0.31 is quite an old version and a few things have changed. It might be a bit much but you could read through the CHANGELOG to figure out how to migrate that code.

You are probably better off by looking at one of the existing examples: https://github.com/libp2p/rust-libp2p/tree/master/examples

Does the compile output any deprecation warnings at all on version 0.47? We usually try to guide users through breaking changes with that. NetworkBehaviourEventProcess and the ability to ignore fields has been removed in libp2p-swarm-derive v0.30.0: https://github.com/libp2p/rust-libp2p/blob/master/swarm-derive/CHANGELOG.md#0300 in favor of tracking that data wherever you are polling Swarm!

[bhagdave]

I had gone through the changelog to get it up to 0.47 and had made the required changes to make sure I had no deprecation warnings when compiling on 0.47. Which is why I think I got a bit stumped when I got the errors when moving to 0.48.

I did look through the examples but could not find one that matched my scenario.

Anyway I will check the swarm derive change log as suggested and see where I get.

THANKS
@thomaseizinger Confimed as Answer. I moved the element out of my NetworkBahviour struct and it compiles fine on 0.48

[thomaseizinger]

Glad it is sorted!

The examples should demonstrate how to get information like mDNS stuff from the event into another behaviour. Basically you match on the return value of swarm.next() and pass it on to the relevant sub-behaviour again.