Note: This CHANGELOG is no longer maintained for newer 0.1.x releases. See instead the github release tags and individual git commits.

0.1.17 - 2017-10-31

  • Add a close method on sink::Wait
  • Undeprecate stream::iter as stream::iter_result
  • Improve performance of wait-related methods
  • Tweak buffered sinks with a 0 capacity to forward directly to the underlying sink.
  • Add FromIterator implementation for FuturesOrdered and FuturesUnordered.

0.1.16 - 2017-09-15

  • A prelude module has been added to glob import from and pick up a whole bunch of useful types
  • sync::mpsc::Sender::poll_ready has been added as an API
  • sync::mpsc::Sender::try_send has been added as an API

0.1.15 - 2017-08-24

  • Improve performance of BiLock methods
  • Implement Clone for FutureResult
  • Forward Stream trait through SinkMapErr
  • Add stream::futures_ordered next to futures_unordered
  • Reimplement Stream::buffered on top of stream::futures_ordered (much more efficient at scale).
  • Add a with_notify function for abstractions which previously required UnparkEvent.
  • Add get_ref/get_mut/into_inner functions for stream take/skip methods
  • Add a Clone implementation for SharedItem and SharedError
  • Add a mpsc::spawn function to spawn a Stream into an Executor
  • Add a reunite function for BiLock and the split stream/sink types to rejoin two halves and reclaim the original item.
  • Add stream::poll_fn to behave similarly to future::poll_fn
  • Add Sink::with_flat_map like Iterator::flat_map
  • Bump the minimum Rust version to 1.13.0
  • Expose AtomicTask in the public API for managing synchronization around task notifications.
  • Unify the Canceled type of the sync and unsync modules.
  • Deprecate the boxed methods. These methods have caused more confusion than they‘ve solved historically, so it’s recommended to use a local extension trait or a local helper instead of the trait-based methods.
  • Deprecate the Stream::merge method as it's less ergonomic than select.
  • Add oneshot::Sender::is_canceled to test if a oneshot is canceled off a task.
  • Deprecates UnboundedSender::send in favor of a method named unbounded_send to avoid a conflict with Sink::send.
  • Deprecate the stream::iter function in favor of an stream::iter_ok adaptor to avoid the need to deal with Result manually.
  • Add an inspect function to the Future and Stream traits along the lines of Iterator::inspect

0.1.14 - 2017-05-30

This is a relatively large release of the futures crate, although much of it is from reworking internals rather than new APIs. The banner feature of this release is that the futures::{task, executor} modules are now available in no_std contexts! A large refactoring of the task system was performed in PR #436 to accommodate custom memory allocation schemes and otherwise remove all dependencies on std for the task module. More details about this change can be found on the PR itself.

Other API additions in this release are:

  • A FuturesUnordered::push method was added and the FuturesUnordered type itself was completely rewritten to efficiently track a large number of futures.
  • A Task::will_notify_current method was added with a slightly different implementation than Task::is_current but with stronger guarantees and documentation wording about its purpose.
  • Many combinators now have get_ref, get_mut, and into_inner methods for accessing internal futures and state.
  • A Stream::concat2 method was added which should be considered the “fixed” version of concat, this one doesn't panic on empty streams.
  • An Executor trait has been added to represent abstracting over the concept of spawning a new task. Crates which only need the ability to spawn a future can now be generic over Executor rather than requiring a tokio_core::reactor::Handle.

As with all 0.1.x releases this PR is intended to be 100% backwards compatible. All code that previously compiled should continue to do so with these changes. As with other changes, though, there are also some updates to be aware of:

  • The task::park function has been renamed to task::current.
  • The Task::unpark function has been renamed to Task::notify, and in general terminology around “unpark” has shifted to terminology around “notify”
  • The Unpark trait has been deprecated in favor of the Notify trait mentioned above.
  • The UnparkEvent structure has been deprecated. It currently should perform the same as it used to, but it's planned that in a future 0.1.x release the performance will regress for crates that have not transitioned away. The primary primitive to replace this is the addition of a push function on the FuturesUnordered type. If this does not help implement your use case though, please let us know!
  • The Task::is_current method is now deprecated, and you likely want to use Task::will_notify_current instead, but let us know if this doesn't suffice!

0.1.13 - 2017-04-05

  • Add forwarding sink/stream impls for stream::FromErr and sink::SinkFromErr
  • Add PartialEq and Eq to mpsc::SendError
  • Reimplement Shared with spawn instead of UnparkEvent

0.1.12 - 2017-04-03

  • Add Stream::from_err and Sink::from_err
  • Allow SendError to be Clone when possible

0.1.11 - 2017-03-13

The major highlight of this release is the addition of a new “default” method on the Sink trait, Sink::close. This method is used to indicate to a sink that no new values will ever need to get pushed into it. This can be used to implement graceful shutdown of protocols and otherwise simply indicates to a sink that it can start freeing up resources.

Currently this method is not a default method to preserve backwards compatibility, but it‘s intended to become a default method in the 0.2 series of the futures crate. It’s highly recommended to audit implementations of Sink to implement the close method as is fit.

Other changes in this release are:

  • A new select combinator, Future::select2 was added for a heterogeneous select.
  • A Shared::peek method was added to check to see if it's done.
  • Sink::map_err was implemented
  • The log dependency was removed
  • Implementations of the Debug trait are now generally available.
  • The stream::IterStream type was renamed to stream::Iter (with a reexport for the old name).
  • Add a Sink::wait method which returns an adapter to use an arbitrary Sink synchronously.
  • A Stream::concat method was added to concatenate a sequence of lists.
  • The oneshot::Sender::complete method was renamed to send and now returns a Result indicating successful transmission of a message or not. Note that the complete method still exists, it's just deprecated.

0.1.10 - 2017-01-30

  • Add a new unsync module which mirrors sync to the extent that it can but is intended to not perform cross-thread synchronization (only usable within one thread).
  • Tweak Shared to work when handles may not get poll'd again.

0.1.9 - 2017-01-18

  • Fix Send/Sync of a few types
  • Add future::tail_fn for more easily writing loops
  • Export SharedItem/SharedError
  • Remove an unused type parameter in from_err

0.1.8 - 2017-01-11

  • Fix some race conditions in the Shared implementation
  • Add Stream::take_while
  • Fix an unwrap in stream::futures_unordered
  • Generalize Stream::for_each
  • Add Stream::chain
  • Add stream::repeat
  • Relax &mut self to &self in UnboundedSender::send

0.1.7 - 2016-12-18

  • Add a Future::shared method for creating a future that can be shared amongst threads by cloning the future itself. All derivative futures will resolve to the same value once the original future has been resolved.
  • Add a FutureFrom trait for future-based conversion
  • Fix a wakeup bug in Receiver::close
  • Add future::poll_fn for quickly adapting a Poll-based function to a future.
  • Add an Either enum with two branches to easily create one future type based on two different futures created on two branches of control flow.
  • Remove the 'static bound on Unpark
  • Optimize send_all and forward to send as many items as possible before calling poll_complete.
  • Unify the return types of the ok, err, and result future to assist returning different varieties in different branches of a function.
  • Add CpuFuture::forget to allow the computation to continue running after a drop.
  • Add a stream::futures_unordered combinator to turn a list of futures into a stream representing their order of completion.

0.1.6 - 2016-11-22

  • Fix Clone bound on the type parameter on UnboundedSender

0.1.5 - 2016-11-22

  • Fix #![no_std] support

0.1.4 - 2016-11-22

This is quite a large release relative to the previous point releases! As with all 0.1 releases, this release should be fully compatible with the 0.1.3 release. If any incompatibilities are discovered please file an issue!

The largest changes in 0.1.4 are the addition of a Sink trait coupled with a reorganization of this crate. Note that all old locations for types/traits still exist, they're just deprecated and tagged with #[doc(hidden)].

The new Sink trait is used to represent types which can periodically over time accept items, but may take some time to fully process the item before another can be accepted. Essentially, a sink is the opposite of a stream. This trait will then be used in the tokio-core crate to implement simple framing by modeling I/O streams as both a stream and a sink of frames.

The organization of this crate is to now have three primary submodules, future, stream, and sink. The traits as well as all combinator types are defined in these submodules. The traits and types like Async and Poll are then reexported at the top of the crate for convenient usage. It should be a relatively rare occasion that the modules themselves are reached into.

Finally, the 0.1.4 release comes with a new module, sync, in the futures crate. This is intended to be the home of a suite of futures-aware synchronization primitives. Currently this is inhabited with a oneshot module (the old oneshot function), a mpsc module for a new multi-producer single-consumer channel, and a BiLock type which represents sharing ownership of one value between two consumers. This module may expand over time with more types like a mutex, rwlock, spsc channel, etc.

Notable deprecations in the 0.1.4 release that will be deleted in an eventual 0.2 release:

  • The TaskRc type is now deprecated in favor of BiLock or otherwise Arc sharing.
  • All future combinators should be accessed through the future module, not the top-level of the crate.
  • The Oneshot and Complete types are now replaced with the sync::oneshot module.
  • Some old names like collect are deprecated in favor of more appropriately named versions like join_all
  • The finished constructor is now ok.
  • The failed constructor is now err.
  • The done constructor is now result.

As always, please report bugs to and we always love feedback! If you‘ve got situations we don’t cover, combinators you'd like to see, or slow code, please let us know!

Full changelog:

  • Improve scalability of buffer_unordered combinator
  • Fix a memory ordering bug in oneshot
  • Add a new trait, Sink
  • Reorganize the crate into three primary modules
  • Add a new sync module for synchronization primitives
  • Add a BiLock sync primitive for two-way sharing
  • Deprecate TaskRc
  • Rename collect to join_all
  • Use a small vec in Events for improved clone performance
  • Add Stream::select for selecting items from two streams like merge but requiring the same types.
  • Add stream::unfold constructor
  • Add a sync::mpsc module with a futures-aware multi-producer single-consumer queue. Both bounded (with backpressure) and unbounded (no backpressure) variants are provided.
  • Renamed failed, finished, and done combinators to err, ok, and result.
  • Add Stream::forward to send all items to a sink, like Sink::send_all
  • Add Stream::split for streams which are both sinks and streams to have separate ownership of the stream/sink halves
  • Improve join_all with concurrency

0.1.3 - 2016-10-24

  • Rewrite oneshot for efficiency and removing allocations on send/recv
  • Errors are passed through in Stream::take and Stream::skip
  • Add a select_ok combinator to pick the first of a list that succeeds
  • Remove the unnecessary SelectAllNext typedef
  • Add Stream::chunks for receiving chunks of data
  • Rewrite stream::channel for efficiency, correctness, and removing allocations
  • Remove Send + 'static bounds on the stream::Empty type

0.1.2 - 2016-10-04

  • Fixed a bug in drop of FutureSender
  • Expose the channel SendError type
  • Add Future::into_stream to convert to a single-element stream
  • Add Future::flatten_to_stream to convert a future of a stream to a stream
  • impl Debug for SendError
  • Add stream::once for a one element stream
  • Accept IntoIterator in stream::iter
  • Add Stream::catch_unwind

0.1.1 - 2016-09-09

Initial release!