Changelog

All notable changes to async-std will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Unreleased

1.5.0 - 2020-02-03

This patch includes various quality of life improvements to async-std. Including improved performance, stability, and the addition of various Clone impls that replace the use of Arc in many cases.

Added

Added links to various ecosystem projects from the README (#660)
Added an example on FromStream for Result<T, E> (#643)
Added stream::pending as "unstable" (#615)
Added an example of stream::timeout to document the error flow (#675)
Implement Clone for DirEntry (#682)
Implement Clone for TcpStream (#689)

Changed

Removed internal comment on stream::Interval (#645)
The "unstable" feature can now be used without requiring the "default" feature (#647)
Removed unnecessary trait bound on stream::FlatMap (#651)
Updated the "broadcaster" dependency used by "unstable" to 1.0.0 (#681)
Updated async-task to 1.2.1 (#676)
task::block_on now parks after a single poll, improving performance in many cases (#684)
Improved reading flow of the "client" part of the async-std tutorial (#550)
Use take_while instead of scan in impl of Product, Sum and FromStream (#667)
TcpStream::connect no longer uses a thread from the threadpool, improving performance (#687)

Fixed

Fixed crate documentation typo (#655)
Fixed documentation for UdpSocket::recv (#648)
Fixed documentation for UdpSocket::send (#671)
Fixed typo in stream documentation (#650)
Fixed typo on sync::JoinHandle documentation (#659)
Removed use of std::error::Error::description which failed CI (#661)
Removed the use of rustfmt's unstable format_code_in_doc_comments option which failed CI (#685)
Fixed a code typo in the task::sleep example (#688)

1.4.0 - 2019-12-20

API Documentation

This patch adds Future::timeout, providing a method counterpart to the future::timeout free function. And includes several bug fixes around missing APIs. Notably we're not shipping our new executor yet, first announced on our blog.

Examples

use async_std::prelude::*;
use async_std::future;
use std::time::Duration;

let fut = future::pending::<()>(); // This future will never resolve.
let res = fut.timeout(Duration::from_millis(100)).await;
assert!(res.is_err()); // The future timed out, returning an err.

Added

Added Future::timeout as "unstable" (#600)

Fixes

Fixed a doc test and enabled it on CI (#597)
Fixed a rendering issue with the stream submodule documentation (#621)
Write::write_fmt's future is now correctly marked as #[must_use] (#628)
Fixed the missing io::Bytes export (#633)
Fixed the missing io::Chain export (#633)
Fixed the missing io::Take export (#633)

1.3.0 - 2019-12-12

API Documentation

This patch introduces Stream::delay, more methods on DoubleEndedStream, and improves compile times. Stream::delay is a new API that's similar to task::sleep, but can be passed as part of as stream, rather than as a separate block. This is useful for examples, or when manually debugging race conditions.

Examples

let start = Instant::now();
let mut s = stream::from_iter(vec![0u8, 1]).delay(Duration::from_millis(200));

// The first time will take more than 200ms due to delay.
s.next().await;
assert!(start.elapsed().as_millis() >= 200);

// There will be no delay after the first time.
s.next().await;
assert!(start.elapsed().as_millis() <= 210);

Added

Added Stream::delay as "unstable" (#309)
Added DoubleEndedStream::next_back as "unstable" (#562)
Added DoubleEndedStream::nth_back as "unstable" (#562)
Added DoubleEndedStream::rfind as "unstable" (#562)
Added DoubleEndedStream::rfold as "unstable" (#562)
Added DoubleEndedStream::try_rfold as "unstable" (#562)
stream::Once now implements DoubleEndedStream (#562)
stream::FromIter now implements DoubleEndedStream (#562)

Changed

Removed our dependency on async-macros, speeding up compilation (#610)

Fixes

Fixed a link in the task docs (#598)
Fixed the UdpSocket::recv example (#603)
Fixed a link to task::block_on (#608)
Fixed an incorrect API mention in task::Builder (#612)
Fixed leftover mentions of futures-preview (#595)
Fixed a typo in the tutorial (#614)
<TcpStream as Write>::poll_close now closes the write half of the stream (#618)

1.2.0 - 2019-11-27

API Documentation

This patch includes some minor quality-of-life improvements, introduces a new Stream::unzip API, and adds verbose errors to our networking types.

This means if you can't connect to a socket, you'll never have to wonder again which address it was you couldn't connect to, instead of having to go through the motions to debug what the address was.

Example

Unzip a stream of tuples into two collections:

use async_std::prelude::*;
use async_std::stream;

let s = stream::from_iter(vec![(1,2), (3,4)]);

let (left, right): (Vec<_>, Vec<_>) = s.unzip().await;

assert_eq!(left, [1, 3]);
assert_eq!(right, [2, 4]);

Added

Added Stream::unzip as "unstable".
Added verbose errors to the networking types.

Changed

Enabled CI on master branch.
Future::join and Future::try_join can now join futures with different output types.

Fixed

Fixed the docs and Debug output of BufWriter.
Fixed a bug in Stream::throttle that made it consume too much CPU.

1.1.0 - 2019-11-21

API Documentation

This patch introduces a faster scheduler algorithm, Stream::throttle, and stabilizes task::yield_now. Additionally we're introducing several more stream APIs, bringing us to almost complete parity with the standard library.

Furthermore our path submodule now returns more context in errors. So if opening a file fails, async-std will tell you which file was failed to open, making it easier to write and debug programs.

Examples

let start = Instant::now();

let mut s = stream::interval(Duration::from_millis(5))
    .throttle(Duration::from_millis(10))
    .take(2);

s.next().await;
assert!(start.elapsed().as_millis() >= 5);

s.next().await;
assert!(start.elapsed().as_millis() >= 15);

s.next().await;
assert!(start.elapsed().as_millis() >= 25);

Added

Added Stream::throttle as "unstable".
Added Stream::count as "unstable".
Added Stream::max as "unstable".
Added Stream::successors as "unstable".
Added Stream::by_ref as "unstable".
Added Stream::partition as "unstable".
Added contextual errors to the path submodule.
Added os::windows::symlink_dir as "unstable".
Added os::windows::symlink_file as "unstable".
Stabilized task::yield_now.

Fixes

We now ignore seek errors when rolling back failed read calls on File.
Fixed a bug where Stream::max_by_key was returning the wrong result.
Fixed a bug where Stream::min_by_key was returning the wrong result.

Changed

Applied various fixes to the tutorial.
Fixed an issue with Clippy.
Optimized an internal code generation macro, improving compilation speeds.
Removed an Unpin bound from stream::Once.
Removed various extra internal uses of pin_mut!.
Simplified Stream::any and Stream::all's internals.
The surf example is now enabled again.
Tweaked some streams internals.
Updated futures-timer to 2.0.0, improving compilation speed.
Upgraded async-macros to 2.0.0.
Stream::merge now uses randomized ordering to reduce overall latency.
The scheduler is now more efficient by keeping a slot for the next task to run. This is similar to Go's scheduler, and Tokio's scheduler.
Fixed the documentation of the channel types to link back to the channel function.

1.0.1 - 2019-11-12

API Documentation

We were seeing a regression in our fs performance, caused by too many long-running tasks. This patch fixes that regression by being more proactive about closing down idle threads.

Changes

Improved thread startup/shutdown algorithm in task::spawn_blocking.
Fixed a typo in the tutorial.

1.0.0 - 2019-11-11

API Documentation

This release marks the 1.0.0 release of async-std; a major milestone for our development. This release itself mostly includes quality of life improvements for all of modules, including more consistent API bounds for a lot of our submodules.

The biggest change is that we're now using the full semver range, major.minor.patch, and any breaking changes to our "stable" APIs will require an update of the major number.

We're excited we've hit this milestone together with you all. Thank you!

Added

Added Future::join as "unstable", replacing future::join!.
Added Future::try_join as "unstable", replacing future::try_join!.
Enabled stable and beta channel testing on CI.
Implemented FromIterator and Extend for PathBuf.
Implemented FromStream for PathBuf.
Loosened the trait bounds of io::copy on "unstable".

Changed

Added a Sync bound to RwLock, resolving a memory safety issue.
Fixed a bug in Stream::take_while where it could continue after it should've ended.
Fixed a bug where our attributes Cargo feature wasn't working as intended.
Improved documentation of Stream::merge, documenting ordering guarantees.
Update doc imports in examples to prefer async-std's types.
Various quality of life improvements to the future submodule.
Various quality of life improvements to the path submodule.
Various quality of life improvements to the stream submodule.

Removed

Removed future::join! in favor of Future::join.
Removed future::try_join! in favor of Future::try_join.

0.99.12 - 2019-11-07

API Documentation

This patch upgrades us to futures 0.3, support for async/await on Rust Stable, performance improvements, and brand new module-level documentation.

Added

Added Future::flatten as "unstable".
Added Future::race as "unstable" (replaces future::select!).
Added Future::try_race as "unstable" (replaces future::try_select!).
Added Stderr::lock as "unstable".
Added Stdin::lock as "unstable".
Added Stdout::lock as "unstable".
Added Stream::copied as "unstable".
Added Stream::eq as "unstable".
Added Stream::max_by_key as "unstable".
Added Stream::min as "unstable".
Added Stream::ne as "unstable".
Added Stream::position as "unstable".
Added StreamExt and FutureExt as enumerable in the prelude.
Added TcpListener and TcpStream integration tests.
Added stream::from_iter.
Added sync::WakerSet for internal use.
Added an example to handle both IP v4 and IP v6 connections.
Added the default Cargo feature.
Added the attributes Cargo feature.
Added the std Cargo feature.

Changed

Fixed a bug in the blocking threadpool where it didn't spawn more than one thread.
Fixed a bug with Stream::merge where sometimes it ended too soon.
Fixed a bug with our GitHub actions setup.
Fixed an issue where our channels could spuriously deadlock.
Refactored the task module.
Removed a deprecated GitHub action.
Replaced futures-preview with futures.
Replaced lazy_static with once_cell.
Replaced all uses of VecDequeue in the examples with stream::from_iter.
Simplified sync::RwLock using the internal sync::WakerSet type.
Updated the path submodule documentation to match std.
Updated the mod-level documentation to match std.

Removed

Removed future::select! (replaced by Future::race).
Removed future::try_select! (replaced by Future::try_race).

0.99.11 - 2019-10-29

This patch introduces async_std::sync::channel, a novel asynchronous port of the ultra-fast Crossbeam channels. This has been one of the most anticipated features for async-std, and we're excited to be providing a first version of this!

In addition to channels, this patch has the regular list of new methods, types, and doc fixes.

Examples

Send and receive items from a channel

// Create a bounded channel with a max-size of 1
let (s, r) = channel(1);

// This call returns immediately because there is enough space in the channel.
s.send(1).await;

task::spawn(async move {
    // This call blocks the current task because the channel is full.
    // It will be able to complete only after the first message is received.
    s.send(2).await;
});

// Receive items from the channel
task::sleep(Duration::from_secs(1)).await;
assert_eq!(r.recv().await, Some(1));
assert_eq!(r.recv().await, Some(2));

Added

Added Future::delay as "unstable"
Added Stream::flat_map as "unstable"
Added Stream::flatten as "unstable"
Added Stream::product as "unstable"
Added Stream::sum as "unstable"
Added Stream::min_by_key
Added Stream::max_by
Added Stream::timeout as "unstable"
Added sync::channel as "unstable".
Added doc links from instantiated structs to the methods that create them.
Implemented Extend + FromStream for PathBuf.

Changed

Fixed an issue with block_on so it works even when nested.
Fixed issues with our Clippy check on CI.
Replaced our uses of cfg_if with our own macros, simplifying the codebase.
Updated the homepage link in Cargo.toml to point to async.rs.
Updated the module-level documentation for stream and sync.
Various typos and grammar fixes.
Removed redundant file flushes, improving the performance of File operations

Removed

Nothing was removed in this release.

0.99.10 - 2019-10-16

This patch stabilizes several core concurrency macros, introduces async versions of Path and PathBuf, and adds almost 100 other commits.

Examples

Asynchronously read directories from the filesystem

use async_std::fs;
use async_std::path::Path;
use async_std::prelude::*;

let path = Path::new("/laputa");
let mut dir = fs::read_dir(&path).await.unwrap();
while let Some(entry) = dir.next().await {
    if let Ok(entry) = entry {
        println!("{:?}", entry.path());
    }
}

Cooperatively reschedule the current task on the executor

use async_std::prelude::*;
use async_std::task;

task::spawn(async {
    let x = fibonnacci(1000); // Do expensive work
    task::yield_now().await;  // Allow other tasks to run
    x + fibonnacci(100)       // Do more work
})

Create an interval stream

use async_std::prelude::*;
use async_std::stream;
use std::time::Duration;

let mut interval = stream::interval(Duration::from_secs(4));
while let Some(_) = interval.next().await {
    println!("prints every four seconds");
}

Added

Added FutureExt to the prelude, allowing us to extend Future
Added Stream::cmp
Added Stream::ge
Added Stream::last
Added Stream::le
Added Stream::lt
Added Stream::merge as "unstable", replacing stream::join!
Added Stream::partial_cmp
Added Stream::take_while
Added Stream::try_fold
Added future::IntoFuture as "unstable"
Added io::BufRead::split
Added io::Write::write_fmt
Added print!, println!, eprint!, eprintln! macros as "unstable"
Added process as "unstable", re-exporting std types only for now
Added std::net re-exports to the net submodule
Added std::path::PathBuf with all associated methods
Added std::path::Path with all associated methods
Added stream::ExactSizeStream as "unstable"
Added stream::FusedStream as "unstable"
Added stream::Product
Added stream::Sum
Added stream::from_fn
Added stream::interval as "unstable"
Added stream::repeat_with
Added task::spawn_blocking as "unstable", replacing task::blocking
Added task::yield_now
Added write! and writeln! macros as "unstable"
Stabilized future::join! and future::try_join!
Stabilized future::timeout
Stabilized path
Stabilized task::ready!

Changed

Fixed BufWriter::into_inner so it calls flush before yielding
Refactored io::BufWriter internals
Refactored net::ToSocketAddrs internals
Removed Travis CI entirely
Rewrote the README.md
Stabilized io::Cursor
Switched bors over to use GitHub actions
Updated the io documentation to match std's io docs
Updated the task documentation to match std's thread docs

Removed

Removed the "unstable" stream::join! in favor of Stream::merge
Removed the "unstable" task::blocking in favor of task::spawn_blocking

0.99.9 - 2019-10-08

This patch upgrades our futures-rs version, allowing us to build on the 1.39 beta. Additionally we've introduced map and for_each to Stream. And we've added about a dozen new FromStream implementations for std types, bringing us up to par with std's FromIterator implementations.

And finally we've added a new "unstable" task::blocking function which can be used to convert blocking code into async code using a threadpool. We've been using this internally for a while now to async-std to power our fs and net::SocketAddr implementations. With this patch userland code now finally has access to this too.

Example

Create a stream of tuples, and collect into a hashmap

let a = stream::once(1u8);
let b = stream::once(0u8);

let s = a.zip(b);

let map: HashMap<u8, u8> = s.collect().await;
assert_eq!(map.get(&1), Some(&0u8));

Spawn a blocking task on a dedicated threadpool

task::blocking(async {
    println!("long-running task here");
}).await;

Added

Added stream::Stream::map
Added stream::Stream::for_each
Added stream::Stream::try_for_each
Added task::blocking as "unstable"
Added FromStream for all std::{option, collections, result, string, sync} types.
Added the path submodule as "unstable".

Changed

Updated futures-preview to 0.3.0-alpha.19, allowing us to build on rustc 1.39.0-beta.
As a consequence of this upgrade, all of our concrete stream implementations now make use of Stream::size_hint to optimize internal allocations.
We now use GitHub Actions through actions-rs, in addition to Travis CI. We intend to fully switch in the near future.
Fixed a bug introduced in 0.99.6 where Unix Domain Listeners would sometimes become unresponsive.
Updated our sync::Barrier docs to match std.
Updated our stream::FromStream docs to match std's FromIterator.

0.99.8 - 2019-09-28

Added

Added README to examples directory.
Added concurrency documentation to the futures submodule.
Added io::Read::take method.
Added io::Read::by_ref method.
Added io::Read::chain method.

Changed

Pin futures-preview to 0.3.0-alpha.18, to avoid rustc upgrade problems.
Simplified extension traits using a macro.
Use the broadcast module with std::sync::Mutex, reducing dependencies.

0.99.7 - 2019-09-26

Added

Added future::join macro as "unstable"
Added future::select macro as "unstable"
Added future::try_join macro as "unstable"
Added future::try_select macro as "unstable"
Added io::BufWriter struct
Added stream::Extend trait
Added stream::Stream::chain method
Added stream::Stream::filter method
Added stream::Stream::inspect method
Added stream::Stream::skip_while method
Added stream::Stream::skip method
Added stream::Stream::step_by method
Added sync::Arc struct from stdlib
Added sync::Barrier struct as "unstable"
Added sync::Weak struct from stdlib
Added task::ready macro as "unstable"

Changed

Correctly marked the pin submodule as "unstable" in the docs
Updated tutorial to have certain functions suffixed with _loop
io traits are now re-exports of futures-rs types, allowing them to be implemented
stream traits are now re-exports of futures-rs types, allowing them to be implemented
prelude::* now needs to be in scope for functions io and stream traits to work

0.99.6 - 2019-09-19

Added

Added stream::Stream::collect as "unstable"
Added stream::Stream::enumerate
Added stream::Stream::fuse
Added stream::Stream::fold
Added stream::Stream::scan
Added stream::Stream::zip
Added stream::join macro as "unstable"
Added stream::DoubleEndedStream as "unstable"
Added stream::FromStream trait as "unstable"
Added stream::IntoStream trait as "unstable"
Added io::Cursor as "unstable"
Added io::BufRead::consume method
Added io::repeat
Added io::Slice and io::SliceMut
Added documentation for feature flags
Added pin submodule as "unstable"
Added the ability to collect a stream of Result<T, E>s into a Result<impl FromStream<T>, E>

Changed

Refactored the scheduling algorithm of our executor to use work stealing
Refactored the network driver, removing 400 lines of code
Removed the Send bound from task::block_on
Removed Unpin bound from impl<T: futures::stream::Stream> Stream for T

0.99.5 - 2019-09-12

Added

Added tests for io::timeout
Added io::BufRead::fill_buf, an async fn counterpart to poll_fill_buf
Added fs::create_dir_all
Added future::timeout, a free function to time out futures after a threshold
Added io::prelude
Added net::ToSocketAddrs, a non-blocking version of std's ToSocketAddrs
Added stream::Stream::all
Added stream::Stream::filter_map
Added stream::Stream::find_map
Added stream::Stream::find
Added stream::Stream::min_by
Added stream::Stream::nth

Changed

Polished the text and examples of the tutorial
cargo fmt on all examples
Simplified internals of TcpStream::connect_to
Modularized our CI setup, enabled a rustfmt fallback, and improved caching
Reduced our dependency on the futures-rs crate, improving compilation times
Split io::Read, io::Write, io::BufRead, and stream::Stream into multiple files
fs::File now flushes more often to prevent flushes during seek
Updated all dependencies
Fixed a bug in the conversion of File into raw handle
Fixed compilation errors on the latest nightly

Removed

0.99.4 - 2019-08-21

Changes

Many small changes in the book, mostly typos
Documentation fixes correcting examples
Now works with recent nightly with stabilised async/await (> 2019-08-21)

0.99.3 - 2019-08-16

Initial beta release

Files

CHANGELOG.md

Latest commit

History

CHANGELOG.md

File metadata and controls

Changelog

Unreleased

1.5.0 - 2020-02-03

Added

Changed

Fixed

1.4.0 - 2019-12-20

Examples

Added

Fixes

1.3.0 - 2019-12-12

Examples

Added

Changed

Fixes

1.2.0 - 2019-11-27

Example

Added

Changed

Fixed

1.1.0 - 2019-11-21

Examples

Added

Fixes

Changed

1.0.1 - 2019-11-12

Changes

1.0.0 - 2019-11-11

Added

Changed

Removed

0.99.12 - 2019-11-07

Added

Changed

Removed

0.99.11 - 2019-10-29

Examples

Added

Changed

Removed

0.99.10 - 2019-10-16

Examples

Added

Changed

Removed

0.99.9 - 2019-10-08

Example

Added

Changed

0.99.8 - 2019-09-28

Added

Changed

0.99.7 - 2019-09-26

Added

Changed

0.99.6 - 2019-09-19

Added

Changed

0.99.5 - 2019-09-12

Added

Changed

Removed

0.99.4 - 2019-08-21

Changes

0.99.3 - 2019-08-16