blob: 8305dececea780562d93ba7720f143366ca63615 [file] [log] [blame]
<!--{
"Title": "Go 1.19 Release Notes",
"Path": "/doc/go1.19"
}-->
<!--
NOTE: In this document and others in this directory, the convention is to
set fixed-width phrases with non-fixed-width spaces, as in
<code>hello</code> <code>world</code>.
Do not send CLs removing the interior tags from such phrases.
-->
<style>
main ul li { margin: 0.5em 0; }
</style>
<h2 id="introduction">DRAFT RELEASE NOTES — Introduction to Go 1.19</h2>
<p>
<strong>
Go 1.19 is not yet released. These are work-in-progress
release notes. Go 1.19 is expected to be released in August 2022.
</strong>
</p>
<h2 id="language">Changes to the language</h2>
<p>
TODO: complete this section
</p>
<h2 id="ports">Ports</h2>
<p>
TODO: complete this section, or delete if not needed
</p>
<h2 id="tools">Tools</h2>
<p>
TODO: complete this section, or delete if not needed
</p>
<h3 id="go-command">Go command</h3>
<p>
TODO: complete this section.
</p>
<!-- https://go.dev/issue/51461 -->
<p>
The <code>-trimpath</code> flag, if set, is now included in the build settings
stamped into Go binaries by <code>go</code> <code>build</code>, and can be
examined using
<a href="https://pkg.go.dev/cmd/go#hdr-Print_Go_version"><code>go</code> <code>version</code> <code>-m</code></a>
or <a href="https://pkg.go.dev/runtime/debug#ReadBuildInfo"><code>debug.ReadBuildInfo</code></a>.
</p>
<p>
<code>go</code> <code>generate</code> now sets the <code>GOROOT</code>
environment variable explicitly in the generator's environment, so that
generators can locate the correct <code>GOROOT</code> even if built
with <code>-trimpath</code>.
</p>
<h4 id="go-unix">New <code>unix</code> build constraint</h4>
<p><!-- CL 389934 -->
The build constraint <code>unix</code> is now recognized
in <code>//go:build</code> lines. The constraint is satisfied
if the target operating system, also known as <code>GOOS</code>, is
a Unix or Unix-like system. For the 1.19 release it is satisfied
if <code>GOOS</code> is one of
<code>aix</code>, <code>android</code>, <code>darwin</code>,
<code>dragonfly</code>, <code>freebsd</code>, <code>hurd</code>,
<code>illumos</code>, <code>ios</code>, <code>linux</code>,
<code>netbsd</code>, <code>openbsd</code>, or <code>solaris</code>.
In future releases the <code>unix</code> constraint may match
additional newly supported operating systems.
</p>
<h2 id="runtime">Runtime</h2>
<p>
TODO: complete this section, or delete if not needed
</p>
<h2 id="compiler">Compiler</h2>
<p>
TODO: complete this section, or delete if not needed
</p>
<h2 id="linker">Linker</h2>
<p>
TODO: complete this section, or delete if not needed
</p>
<h2 id="library">Core library</h2>
<p>
TODO: complete this section
</p>
<h3 id="minor_library_changes">Minor changes to the library</h3>
<p>
As always, there are various minor changes and updates to the library,
made with the Go 1 <a href="/doc/go1compat">promise of compatibility</a>
in mind.
</p>
<p>
TODO: complete this section
</p>
<dl id="image/draw"><dt><a href="/pkg/image/draw/">image/draw</a></dt>
<dd>
<p><!-- CL 396795 -->
<code>Draw</code> with the <code>Src</code> operator preserves
non-premultiplied-alpha colors when destination and source images are
both <code>*image.NRGBA</code> (or both <code>*image.NRGBA64</code>).
This reverts a behavior change accidentally introduced by a Go 1.18
library optimization, to match the behavior in Go 1.17 and earlier.
</p>
</dd>
</dl><!-- image/draw -->
<dl id="net"><dt><a href="/pkg/net/">net</a></dt>
<dd>
<p><!-- CL 386016 -->
The pure Go resolver will now use EDNS(0) to include a suggested
maximum reply packet length, permitting reply packets to contain
up to 1232 bytes (the previous maximum was 512).
In the unlikely event that this causes problems with a local DNS
resolver, setting the environment variable
<code>GODEBUG=netdns=cgo</code> to use the cgo-based resolver
should work.
Please report any such problems on <a href="/issue/new">the
issue tracker</a>.
</p>
<p><!-- CL 396877 -->
When a net package function or method returns an "I/O timeout"
error, the error will now satisfy <code>errors.Is(err,
context.DeadlineExceeded)</code>. When a net package function
returns an "operation was canceled" error, the error will now
satisfy <code>errors.Is(err, context.Canceled)</code>.
These changes are intended to make it easier for code to test
for cases in which a context cancelation or timeout causes a net
package function or method to return an error, while preserving
backward compatibility for error messages.
</p>
</dd>
</dl><!-- net -->
<dl id="os/exec"><dt><a href="/pkg/os/exec/">os/exec</a></dt>
<dd><!-- https://go.dev/issue/50599 -->
<p>
An <code>exec.Cmd</code> with a non-empty <code>Dir</code> and a
nil <code>Env</code> now implicitly sets the <code>PWD</code> environment
variable for the subprocess to match <code>Dir</code>.
</p>
<p>
The new method <code>(*exec.Cmd).Environ</code> reports the
environment that would be used to run the command, including the
aforementioned <code>PWD</code> variable.
</p>
</dd>
</dl> <!-- os/exec -->
<dl id="runtime"><dt><a href="/pkg/runtime/">runtime</a></dt>
<dd>
<p><!-- https://go.dev/issue/51461 -->
The <code>GOROOT</code> function now returns the empty string
(instead of <code>"go"</code>) when the binary was built with
the <code>-trimpath</code> flag set and the <code>GOROOT</code>
variable is not set in the process environment.
</p>
</dd>
</dl><!-- runtime -->
<dl id="strconv"><dt><a href="/pkg/strconv/">strconv</a></dt>
<dd>
<p><!-- CL 397255 -->
<a href="/pkg/strconv/#strconv.Quote"><code>strconv.Quote</code></a>
and related functions now quote the rune 007F as <code>\x7f</code>,
not <code>\u007f</code>.
</p>
</dd>
</dl><!-- strconv -->