async-std has officially been discontinued. We recommend that all users and libraries migrate to the excellentsmol project.

We createdasync-std to demonstrate the value of making a library as close tostd as possible, but async. We think that demonstration was successful, and we hope it will influence future design and development directions of async instd. However, in the meantime, thesmol project came about and provided a great executor and libraries for asynchronous use in the Rust ecosystem. We think that resources would be better spent consolidating aroundsmol, rather than continuing to provide occasional maintenance ofasync-std. As such, we recommend that all users ofasync-std, and all libraries built onasync-std, switch tosmol instead.

In addition to thesmol project as a direct replacement, you may find other parts of the futures ecosystem useful, includingfutures-concurrency,async-io,futures-lite, andasync-compat.

Added

• IO Safety traits implementations

Changed

• Various dependencies updates
• ExportBufReadExt andSeekExt fromasync_std::io

This release stabilizes some long-awaited APIs that help people build async interfaces and interoperate with other APIs.

Added

• task::spawn_blocking is now stabilized. We consider it a fundamental API for bridging between blocking code and async code, and we widely use it within async-std's own implementation.
• AddTryFrom implementations to convertTcpListener,TcpStream,UdpSocket,UnixDatagram,UnixListener, andUnixStream to their synchronous equivalents, including putting them back into blocking mode.

Changed

• async-std no longer depends onnum_cpus; it uses functionality in the standard library instead (viaasync-global-executor).
• Miscellaneous documentation fixes and cleanups.

This release improves compile times by up to 55% on initial builds, and up to 75% on recompilation. Additionally we've added a few new APIs and made some tweaks.

Added

• TcpListener::into_incoming to convert aTcpListener into a stream of incoming TCP connections

Removed

• The internalextension_trait macro had been removed. This drastically improves compile times forasync-std, but changes the way our documentation is rendered. This is a cosmetic change only, and all existing code should continue to work as it did be
  fore.

Changed

• Some internal code has been de-macro-ified, making for quicker compile times.
• We now use the default recursion limit.

Docs

• Several docs improvements / fixes.

Happy New Year everyone! This patch stabilizes theasync_std::channel
submodule, removes the deprecatedsync::channel types, and introduces the
tokio1 feature.

New Channels

As part of our1.8.0 release last month we introduced the new
async_std::channel submodule and deprecated the unstable
async_std::sync::channel types. You can read our full motiviation for this
change in the last patch notes. But the short version is that the old
channels had some fundamental problems, and thesync submodule is a bit of
a mess.

This release ofasync-std promotesasync_std::channel to stable, and
fully removes theasync_std::sync::channel types. In practice many
libraries have already been upgraded to the new channels in the past month,
and this will enable much of the ecosystem to switch off "unstable" versions
ofasync-std.

use async_std::channel;let(sender, receiver) = channel::unbounded();assert_eq!(sender.send("Hello").await,Ok(()));assert_eq!(receiver.recv().await,Ok("Hello"));

Tokio 1.0 compat

The Tokio project recently released version 1.0 of their runtime, and the
async-std team would like to congratulate the Tokio team on achieving this
milestone.

This release ofasync-std adds thetokio1 feature flag, enabling Tokio's
TLS constructors to be initialized within theasync-std runtime. This is in
addition to thetokio02 andtokio03 feature flags which we were already
exposing.

In terms of stability it's worth noting that we will continue to provide
support for thetokio02,tokio03, andtokio1 on the current major
release line ofasync-std. These flags are part of our public API, and
removing compat support for older Tokio versions is considered a breaking
change.

Added

• Added thetokio1 feature (#924)
• Stabilized theasync_std::channel submodule (#934)

Removed

• Removed deprecatedsync::channel (#933)

Fixed

• Fixed a typo for [sic]FuturesExt trait (#930)
• Update the link tocargo-edit in the installation section of the docs (#932)
• Fixed a small typo for stream (#926)

Internal

• Updatedrand to 0.8 (#923)
• MigratedRwLock andBarrier to use theasync-lock crate internally (#925)
• Replaced uses of deprecated thecompare_and_swap method withcompare_exchange (#927)

This patch introducesasync_std::channel, a new submodule for our async channels implementation.channels have been one of async-std's most requested features, and have existed as "unstable" for the past year. We've been cautious about stabilizing channels, and this caution turned out to be warranted: we realized our channels could hang indefinitely under certain circumstances, and people ended up expressing a need for unbounded channels.

So today we're introducing the newasync_std::channel submodule which exports theasync-channel crate, and we're marking the older unstableasync_std::sync::channel API as "deprecated". This release includes both APIs, but we intend to stabilizeasync_std::channel and remove the older API in January. This should give dependent projects a month to upgrade, though we can extend that if it proves to be too short.

The rationale for adding a new top-levelchannel submodule, rather than extendingsync is that thestd::sync andasync_std::sync submodule are a bit of a mess, and the libs team has been talking about splittingstd::sync up into separate modules. The stdlib has to guarantee it'll forever be backwards compatible, butasync-std does not (we fully expect a 2.0 once we have async closures & traits). So we're experimenting with this change beforestd does, with the expectation that this change can serve as a data point when the libs team decides how to proceed in std.

Added

• async_std::channel as "unstable"#915
• async_std::process as "unstable"#916

Fixed

• Fixed mentions of thetokio03 flags in the docs#909
• Fixed a double drop issue inStreamExt::cycle#903

Internal

• updatedpin-project tov0.2.0

docs.rs documentation

This patch adds a feature to enable compatibility with the newtokio 0.3.0 release, and updates internal dependencies.

Tokio 0.3.x compat

Since earlier this yearasync-std has shipped with atokio-02 feature flag that enables libraries written for thetokio runtime to work onasync-std as well. When this flag is enabledasync-std ensures that whenever it spawns a thread on its executor, the right tokio-specific thread state is initialized for it. That means no morethread 'main' panicked at 'not currently running on the Tokio runtime.' errors when runningasync-std andtokio in the same application.

This patch introduces a new feature flag:tokio-03 which enables the same mechanism for the latest version of thetokio runtime. As applications migrate fromtokio 0.2.x to 0.3.x, mixing dependencies that use bothasync-std andtokio will continue to work.

Added

• Addtokio03 feature flag (#895)

Internal

• chore: update dependencies (#897)

Fixed

• FixTcpListener::incoming. (#889)
• Fix tokio compatability flag. (#882)

Added

• AddedUdpSocket::peek andUdpSocket::peek_from (#853)

Changed

• Extracted the executor intoasync-global-executor (#867)

• Updated various dependencies

Fixed

• EnsureUnixStream::into_raw_fd doesn't close the file descriptor (#855)
• Fixed wasm builds and ensured better dependency management depending on the compile target (#863)

Added

Changed

• Switched from smol to individual executor parts. (#836)
• Replaced internalMutex implementation withasync-mutex. (#822)

Fixed

• Added missingSend guards toStream::collect. (#665)