go/doc/go1.15.html

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<h2 id="introduction">DRAFT RELEASE NOTES — Introduction to Go 1.15</h2>

<p>
  <strong>
    Go 1.15 is not yet released. These are work-in-progress
    release notes. Go 1.15 is expected to be released in August 2020.
  </strong>
</p>

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

<p>
TODO
</p>

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

<p>
TODO
</p>

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

<p>
TODO
</p>

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

<p><!-- golang.org/issue/37367 -->
  The <code>GOPROXY</code> environment variable now supports skipping proxies
  that return errors. Proxy URLs may now be separated with either commas
  (<code>,</code>) or pipe characters (<code>|</code>). If a proxy URL is
  followed by a comma, the <code>go</code> command will only try the next proxy
  in the list after a 404 or 410 HTTP response. If a proxy URL is followed by a
  pipe character, the <code>go</code> command will try the next proxy in the
  list after any error. Note that the default value of <code>GOPROXY</code>
  remains <code>https://proxy.golang.org,direct</code>, which does not fall
  back to <code>direct</code> in case of errors.
</p>

<p>
TODO
</p>

<h4 id="go-test"><code>go</code> <code>test</code></h4>

<p><!-- https://golang.org/issue/36134 -->
  Changing the <code>-timeout</code> flag now invalidates cached test results. A
  cached result for a test run with a long timeout will no longer count as
  passing when <code>go</code> <code>test</code> is re-invoked with a short one.
</p>

<h4 id="go-flag-parsing">Flag parsing</h4>

<p><!-- https://golang.org/cl/211358 -->
  Various flag parsing issues in <code>go</code> <code>test</code> and
  <code>go</code> <code>vet</code> have been fixed. Notably, flags specified
  in <code>GOFLAGS</code> are handled more consistently, and
  the <code>-outputdir</code> flag now interprets relative paths relative to the
  working directory of the <code>go</code> command (rather than the working
  directory of each individual test).
</p>

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

<p>
TODO
</p>


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

<p>
TODO
</p>

<dl id="testing"><dt><a href="/pkg/testing/">testing</a></dt>
  <dd>
    <p><!-- golang.org/issue/28135 -->
      The <code>testing.T</code> type now has a <code>Deadline</code> method
      that reports the time at which the test binary will have exceeded its
      timeout.
    </p>
    <p><!-- golang.org/issue/34129 -->
      A <code>TestMain</code> function is no longer required to call
      <code>os.Exit</code>. If a <code>TestMain</code> function returns,
      the test binary will call <code>os.Exit</code> with the value returned
      by <code>m.Run</code>.
    </p>
  </dd>
</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>

<dl id="flag"><dt><a href="/pkg/flag/">flag</a></dt>
  <dd>
    <p><!-- CL 221427 -->
      When the flag package sees <code>-h</code> or <code>-help</code>, and
      those flags are not defined, the flag package prints a usage message.
      If the <a href=/pkg/flag/#FlagSet><code>FlagSet</code></a> was created with
      <a href=/pkg/flag/#ExitOnError><code>ExitOnError</code></a>,
      <a href=/pkg/flag/#FlagSet.Parse><code>FlagSet.Parse</code></a> would then
      exit with a status of 2. In this release, the exit status for <code>-h</code>
      or <code>-help</code> has been changed to 0. In particular, this applies to
      the default handling of command line flags.
    </p>
  </dd>
</dl>

<dl id="pkg-runtime"><dt><a href="/pkg/runtime/">runtime</a></dt>
  <dd>
    <p><!-- CL 221779 -->
      If <code>panic</code> is invoked with a value whose type is derived from any
      of: <code>bool</code>, <code>complex64</code>, <code>complex128</code>, <code>float32</code>, <code>float64</code>,
      <code>int</code>, <code>int8</code>, <code>int16</code>, <code>int32</code>, <code>int64</code>, <code>string</code>,
      <code>uint</code>, <code>uint8</code>, <code>uint16</code>, <code>uint32</code>, <code>uint64</code>, <code>uintptr</code>,
      then the value will be printed, instead of just its address.
    </p>
  </dd>
</dl>

<dl id="sync"><dt><a href="/pkg/sync/">sync</a></dt>
  <dd>
    <p><!-- CL 205899, golang.org/issue/33762 -->
      The new method
      <a href="/pkg/sync/#Map.LoadAndDelete"><code>Map.LoadAndDelete</code></a>
      atomically deletes a key and returns the previous value if present.
    </p>
    <p><!-- CL 205899 -->
      The method
      <a href="/pkg/sync/#Map.Delete"><code>Map.Delete</code></a>
      is more efficient.
    </p>
</dl><!-- sync -->

<dl id="testing"><dt><a href="/pkg/testing/">testing</a></dt>
  <dd>
    <p><!-- CL 226877, golang.org/issue/35998 -->
       The new methods
       <a href="/pkg/testing/#T.TempDir"><code>T.TempDir</code></a> and
       <a href="/pkg/testing/#B.TempDir"><code>B.TempDir</code></a> and
       return temporary directories that are automatically cleaned up
       at the end of the test.
    </p>
  </dd>
</dl><!-- testing -->

<dl id="time"><dt><a href="/pkg/time/">time</a></dt>
  <dd>
    <p><!-- CL 220424, CL 217362, golang.org/issue/33184 -->
       The new method
       <a href="/pkg/time/#Ticker.Reset"><code>Ticker.Reset</code></a>
       supports changing the duration of a ticker.
    </p>
  </dd>
</dl><!-- time -->