BREAKING-CHANGES.md

Breaking Changes by Version

0.6.0

• Sealed RefCounter, MessageChannel, and MessageSink traits

0.5.0

• The SyncHandler trait has been removed. This simplifies the API and should not change the performance on stable.
  • How to upgrade: change all implementations of the SyncHandler trait to the normal Handler trait.
• All Actor lifecycle messages are now async. This allows to do more kinds of things in lifecycle methods, while adding no restrictions.
  • How to upgrade: add async to the function definition of all actor lifecycle methods, add #[async_trait::async_trait] to the impl Actor block.
• Actor now requires Send to implement. Previously, the trait itself did not, but using it did require Send.
  • How to upgrade: you probably never had a non-Send actor in the first place.
• The {Weak}{Address|MessageChannel}::attach_stream methods now require that the actor implements Handler<M> where M: Into<KeepRunning> + Send. This is automatically implemented for (), returning KeepRunning::Yes. This allows the user more control over the future spawned by attach_stream, but is breaking if the message returned did not implement Into<KeepRunning>.
  • How to upgrade: implement Into<KeepRunning> for all message types used in attach_stream. To mimic previous behaviour, return KeepRunning::Yes in the implementation.
• Address and WeakAddress lost their Sink implementations. They can now be turned into Sinks by calling .into_sink().
  • How to upgrade: convert any addresses to be used as sinks into sinks with .into_sink(), cloning where necessary.
• {Address|MessageChannel}Ext were removed in favour of inherent implementations,
  • How to upgrade: in most cases, this will not have broken anything. If it is directly imported, remove the import. If you need to be generic over weak and strong addresses, be generic over Address<A, Rc> where Rc: RefCounter for addresses and use MessageChannel<M> trait objects.
• {Weak}MessageChannel became traits rather than concrete types. In order to use them, simply cast an address to the correct trait object (e.g &addr as &dyn MessageChannel<M> or Box::new(addr)). The into_channel and channel methods were also removed.
  • How to upgrade: replace {into_}channel calls with casts to trait objects, and replace references to the old types with trait objects, boxed if necessary. If you were using the Sink implementations of these types, first create an AddressSink through .into_sink(), and then cast it to a MessageSink trait object.
• Address::into_downgraded was removed. This did nothing different to downgrade, except dropping the address after the call.
  • How to upgrade: Simply call Address::downgrade, dropping the strong address afterwards if needed.
• Some types were moved out of the root crate and into modules.
  • How to upgrade: search for the type's name in the documentation and refer to it by its new path.
• Actor::spawn and Actor::create now take anOption<usize> for the mailbox size.
  • How to upgrade: choose a suitable size of mailbox for each spawn call, or pass None to give them unbounded mailboxes.
• Many context methods now return Result<..., ActorShutdown> to represent failures due to the actor having been shut down.

0.4.0

• The stable feature was removed. In order to enable the nightly API, enable the new nightly feature. Edit: as of 0.5.0, the nightly API has been removed.

0.3.0

• The default API of the Handler trait has now changed to an async_trait so that xtra can compile on stable.
  • How to upgrade, alternative 1: change the implementations by annotating the implementation with #[async_trait], removing Responder and making handle an async fn which directly returns the message's result.
  • How to upgrade, alternative 2: if you want to avoid the extra box, you can disable the default stable feature in your Cargo.toml to keep the old API.

0.2.0

• Removal of the with-runtime feature
  • How to upgrade: you probably weren't using this anyway, but rather use with-tokio-* or with-async_std-* instead.
• Address methods were moved to AddressExt to accommodate new Address types
  • How to upgrade: add use xtra::AddressExt to wherever address methods are used (or, better yet, use xtra::prelude::*)
• All *_async methods were removed. Asynchronous and synchronous messages now use the same method for everything.
  • How to upgrade: simply switch from the [x]_async method to the [x] method.
• AsyncHandler was renamed to Handler, and the old Handler to SyncHandler. Also, a Handler and SyncHandler implementation can no longer coexist.
  • How to upgrade: rename all Handler implementations to SyncHandler, and all AsyncHandler implementations to Handler.