go/doc/go1.14.html

<!--{
        "Title": "Go 1.14 Release Notes",
        "Path":  "/doc/go1.14",
        "Template": true
}-->

<!--
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 1.14</h2>

<p>
  <strong>
    Go 1.14 is not yet released. These are work-in-progress
    release notes. Go 1.14 is expected to be released in February 2020.
  </strong>
</p>

<h2 id="language">Changes to the language</h2>

<p>
TODO
</p>

<h2 id="ports">Ports</h2>

<p>
  TODO: is Dragonfly passing? On both Dragonfly release & tip? (ABI
  change happened) Does the net package's interface APIs work on both?
  https://golang.org/issue/34368.
</p>

<p>
  TODO: is Illumos up with a builder and passing?
  https://golang.org/issue/15581.
</p>

<p>
  TODO: announce something about the Go Solaris port? Solaris itself
  is unmaintained? The builder is still running at Oracle, but the
  employee who set it up left the company and we have no way to
  maintain it.
</p>

<h3 id="darwin">Darwin</h3>

<p><!-- golang.org/issue/34749 -->
  Go 1.14 is the last Go release to support 32-bit binaries on
  macOS (the <code>darwin/386</code> port). They are no longer
  supported by macOS, starting with macOS 10.15 (Catalina).
  Go continues to support the 64-bit <code>darwin/amd64</code> port.
</p>

<p><!-- golang.org/issue/34751 -->
  Go 1.14 will likely be the last Go release to support 32-bit
  binaries on iOS, iPadOS, watchOS, and tvOS
  (the <code>darwin/arm</code> port). Go continues to support the
  64-bit <code>darwin/arm64</code> port.
</p>

<h3 id="freebsd">FreeBSD</h3>

<p><!-- golang.org/issue/24715 -->
  Go now supports the 64-bit ARM architecture on FreeBSD (the
  <code>freebsd/arm64</code> port).
</p>

<h3 id="nacl">Native Client (NaCl)</h3>

<p><!-- golang.org/issue/30439 -->
  As <a href="go1.13#ports">announced</a> in the Go 1.13 release notes,
  Go 1.14 drops support for the Native Client platform (<code>GOOS=nacl</code>).
</p>

<h2 id="tools">Tools</h2>

<p>
TODO
</p>

<h3 id="go-command">Go command</h3>

<h4 id="vendor">Vendoring</h4>
<!-- golang.org/issue/33848 -->

<p>
  When the main module contains a top-level <code>vendor</code> directory and
  its <code>go.mod</code> file specifies <code>go</code> <code>1.14</code> or
  higher, the <code>go</code> command now defaults to <code>-mod=vendor</code>
  for operations that accept that flag. A new value for that flag,
  <code>-mod=mod</code>, causes the <code>go</code> command to instead load
  modules from the module cache (as when no <code>vendor</code> directory is
  present).
</p>

<p>
  When <code>-mod=vendor</code> is set (explicitly or by default), the
  <code>go</code> command now verifies that the main module's
  <code>vendor/modules.txt</code> file is consistent with its
  <code>go.mod</code> file.
</p>

<p>
  <code>go</code> <code>list</code> <code>-m</code> no longer silently omits
  transitive dependencies that do not provide packages in
  the <code>vendor</code> directory. It now fails explicitly if
  <code>-mod=vendor</code> is set.
</p>

<h4 id="go-flags">Flags</h4>

<p><!-- golang.org/issue/32502, golang.org/issue/30345 -->
  The <code>go</code> <code>get</code> command no longer accepts
  the <code>-mod</code> flag. Previously, the flag's setting either
  <a href="https://golang.org/issue/30345">was ignored</a> or
  <a href="https://golang.org/issue/32502">caused the build to fail</a>.
</p>

<p><!-- golang.org/issue/31481 -->
  <code>-modcacherw</code> is a new flag that instructs the <code>go</code>
  command to leave newly-created directories in the module cache at their
  default permissions rather than making them read-only.
  The use of this flag makes it more likely that tests or other tools will
  accidentally add files not included in the module's verified checksum.
  However, it allows the use of <code>rm</code> <code>-rf</code>
  (instead of <code>go</code> <code>clean</code> <code>-modcache</code>)
  to remove the module cache.
</p>

<p><!-- golang.org/issue/34506 -->
  <code>-modfile=file</code> is a new flag that instructs the <code>go</code>
  command to read (and possibly write) an alternate go.mod file instead of the
  one in the module root directory. A file named "go.mod" must still be present
  in order to determine the module root directory, but it is not
  accessed. When <code>-modfile</code> is specified, an alternate go.sum file
  is also used: its path is derived from the <code>-modfile</code> flag by
  trimming the ".mod" extension and appending ".sum".
</p>

<h4 id="incompatible-versions"><code>+incompatible</code> versions</h4>
<!-- golang.org/issue/34165 -->

<p>
  If the latest version of a module contains a <code>go.mod</code> file,
  <code>go</code> <code>get</code> will no longer upgrade to an
  <a href="/cmd/go/#hdr-Module_compatibility_and_semantic_versioning">incompatible</a>
  major version of that module unless such a version is requested explicitly
  or is already required.
  <code>go</code> <code>list</code> also omits incompatible major versions
  for such a module when fetching directly from version control, but may
  include them if reported by a proxy.
</p>

<h4 id="module-downloading">Module downloading</h4>

<p><!-- golang.org/issue/26092 -->
  The <code>go</code> command now supports Subversion repositories in module mode.
</p>

<p><!-- golang.org/issue/30748 -->
  The <code>go</code> command now includes snippets of plain-text error messages
  from module proxies and other HTTP servers.
  An error message will only be shown if it is valid UTF-8 and consists of only
  graphic characters and spaces.
</p>

<h2 id="runtime">Runtime</h2>

<p>
TODO
</p>

<p><!-- CL 171844 and many others -->
  Internal timers, used by
  <a href="/pkg/time/#After"><code>time.After</code></a>,
  <a href="/pkg/time/#Tick"><code>time.Tick</code></a>,
  <a href="/pkg/net/#Conn"><code>net.Conn.SetDeadline</code></a>,
  and friends, are more efficient, with less lock contention and fewer
  context switches.
  This is a performance improvement that should not cause any user
  visible changes.
</p>

<h2 id="library">Core library</h2>

<p>
TODO
</p>

<dl id="bytes/hash"><dt><a href="/pkg/bytes/hash/">bytes/hash</a></dt>
  <dd>
    <p><!-- CL 186877 -->
      TODO: <a href="https://golang.org/cl/186877">https://golang.org/cl/186877</a>: add hashing package for bytes and strings
    </p>

</dl><!-- bytes/hash -->

<dl id="crypto/tls"><dt><a href="/pkg/crypto/tls/">crypto/tls</a></dt>
  <dd>
    <p><!-- CL 191976 -->
      TODO: <a href="https://golang.org/cl/191976">https://golang.org/cl/191976</a>: remove SSLv3 support
    </p>

    <p><!-- CL 191999 -->
      TODO: <a href="https://golang.org/cl/191999">https://golang.org/cl/191999</a>: remove TLS 1.3 opt-out
    </p>

    <p><!-- CL 174329 -->
      The <code>tls</code> package no longer supports NPN and now only
      supports ALPN. In previous releases it supported both. There are
      no API changes and code should function identically as before.
      Most other clients & servers have already removed NPN support in
      favor of the standardized ALPN.
    </p>

</dl><!-- crypto/tls -->

<dl id="encoding/asn1"><dt><a href="/pkg/encoding/asn1/">encoding/asn1</a></dt>
  <dd>
    <p><!-- CL 126624 -->
      TODO: <a href="https://golang.org/cl/126624">https://golang.org/cl/126624</a>: handle ASN1&#39;s string type BMPString
    </p>

</dl><!-- encoding/asn1 -->

<dl id="mime"><dt><a href="/pkg/mime/">mime</a></dt>
  <dd>
    <p><!-- CL 186927 -->
      TODO: <a href="https://golang.org/cl/186927">https://golang.org/cl/186927</a>: update type of .js and .mjs files to text/javascript
    </p>

</dl><!-- mime -->

<dl id="math"><dt><a href="/pkg/math/">math</a></dt>
  <dd>
    <p><!-- CL 127458 -->
      The new <a href="/pkg/math/#FMA"><code>FMA</code></a> function
      computes <code>x*y+z</code> in floating point with no
      intermediate rounding of the <code>x*y</code>
      computation. Several architectures implement this computation
      using dedicated hardware instructions for additional performance.
    </p>

</dl><!-- math -->

<dl id="plugin"><dt><a href="/pkg/plugin/">plugin</a></dt>
  <dd>
    <p><!-- CL 191617 -->
      TODO: <a href="https://golang.org/cl/191617">https://golang.org/cl/191617</a>: add freebsd/amd64 plugin support
    </p>

</dl><!-- plugin -->

<dl id="reflect">

<dt><a href="/pkg/reflect/">reflect</a></dt>
  <dd>
    <p><!-- CL 85661 -->
      <a href="/pkg/reflect#StructOf"><code>StructOf</code></a> now
      supports creating struct types with unexported fields, by
      setting the <code>PkgPath</code> field in
      a <code>StructField</code> element.
    </p>

</dl><!-- reflect -->

<dl id="runtime"><dt><a href="/pkg/runtime/">runtime</a></dt>
  <dd>
    <p><!-- CL 187739 -->
      TODO: <a href="https://golang.org/cl/187739">https://golang.org/cl/187739</a>: treat CTRL_CLOSE_EVENT, CTRL_LOGOFF_EVENT, CTRL_SHUTDOWN_EVENT as SIGTERM on Windows
    </p>

    <p><!-- CL 188297 -->
      TODO: <a href="https://golang.org/cl/188297">https://golang.org/cl/188297</a>: don&#39;t forward SIGPIPE on macOS
    </p>

</dl><!-- runtime -->

<dl id="testing"><dt><a href="/pkg/testing/">testing</a></dt>
  <dd>
    <p><!-- CL 201359 -->
       The testing package now supports cleanup functions, called after
       a test or benchmark has finished, by calling
       <a href="/pkg/testing#T.Cleanup"><code>T.Cleanup</code></a> or
       <a href="/pkg/testing#B.Cleanup"><code>B.Cleanup</code></a> respectively.
    </p>
</dl><!-- testing -->

<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
</p>