go/doc/go1.20.html

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<h2 id="introduction">DRAFT RELEASE NOTES — Introduction to Go 1.20</h2>

<p>
  <strong>
    Go 1.20 is not yet released. These are work-in-progress
    release notes. Go 1.20 is expected to be released in February 2023.
  </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>

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

<p><!-- https://go.dev/issue/38687, CL 421440 -->
  TODO: <a href="https://go.dev/cl/421440">https://go.dev/cl/421440</a>: cmd/go: add go generate -skip flag
</p>

<p><!-- https://go.dev/issue/45454 -->
  TODO: <a href="https://go.dev/issue/45454">https://go.dev/issue/45454</a>: provide build tags for architecture environment variables
</p>

<p>
  The Go distribution no longer ships with pre-compiled <code>.a</code>
  files for most of the packages in <code>GOROOT</code>, now only including
  .a files for the five packages in <code>GOROOT</code> that use <code>cgo</code>.
  Instead, those packages will be built as needed and cached in the build
  cache, as is already done for non-<code>main</code> packages outside
  <code>GOROOT</code>. Further, <code>go</code> <code>install</code> will
  also not install <code>.a</code> files for <code>GOROOT</code> packages
  except for those that use <code>cgo</code>. These changes are intended to
  reduce the size of the Go distribution, in some cases by up to two-thirds.
</p>

<p><!-- https://go.dev/issue/37015 -->
  When the main module is located within <code>GOPATH/src</code>,
  <code>go</code> <code>install</code> no longer installs libraries for
  non-<code>main</code> packages to <code>GOPATH/pkg</code>,
  and <code>go</code> <code>list</code> no longer reports a <code>Target</code>
  field for such packages. (In module mode, compiled packages are stored in the
  <a href="https://pkg.go.dev/cmd/go#hdr-Build_and_test_caching">build cache</a>
  only, but <a href="https://go.dev/issue/37015">a bug</a> had caused
  the <code>GOPATH</code> install targets to unexpectedly remain in effect.)
</p>

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

<p><!-- https://go.dev/issue/48187 -->
  The <code>go</code> <code>version</code> <code>-m</code> command
  now supports reading more types of Go binaries, most notably, Windows DLLs
  built with <code>go</code> <code>build</code> <code>-buildmode=c-shared</code>
  and Linux binaries without execute permission.
</p>

<h3 id="vet">Vet</h3>

<p><!-- https://go.dev/issue/48801, CL 354010 -->
  TODO: <a href="https://go.dev/issue/48801">https://go.dev/issue/48801</a>: check for time formats with 2006-02-01
</p>

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

<p>
  TODO: complete this section, or delete if not needed
</p>

<h2 id="compiler">Compiler</h2>

<p><!-- https://go.dev/issue/49390 -->
  TODO: <a href="https://go.dev/issue/49390">https://go.dev/issue/49390</a>: clarify whether "-l" and "-N" compiler flags are actually supported
</p>

<h2 id="linker">Linker</h2>

<p>
  TODO: complete this section, or delete if not needed
</p>

<h2 id="bootstrap">Bootstrap</h2>

<p><!-- https://go.dev/issue/44505 -->
  TODO: <a href="https://go.dev/issue/44505">https://go.dev/issue/44505</a>: adopt Go 1.17.13 as bootstrap toolchain for Go 1.20
</p>

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

<h3 id="crypto/ecdh">New <code>crypto/ecdh</code> package</h3>

<p><!-- https://go.dev/issue/52221, CL 398914 -->
  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.
  There are also various performance improvements, not enumerated here.
</p>

<p>
  TODO: complete this section
</p>

<dl id="bytes"><dt><a href="/pkg/bytes/">bytes</a></dt>
  <dd>
    <p><!-- CL 407176 -->
      TODO: <a href="https://go.dev/cl/407176">https://go.dev/cl/407176</a>: strings, bytes: add CutPrefix and CutSuffix
    </p>

    <p><!-- CL 359675 -->
      TODO: <a href="https://go.dev/cl/359675">https://go.dev/cl/359675</a>: bytes: add Clone function
    </p>
  </dd>
</dl><!-- bytes -->

<dl id="crypto/elliptic"><dt><a href="/pkg/crypto/elliptic/">crypto/elliptic</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/34648 -->
      TODO: <a href="https://go.dev/issue/34648">https://go.dev/issue/34648</a>: automatically upgrade CurveParams for known curves and deprecate custom ones
    </p>
  </dd>
</dl><!-- crypto/elliptic -->

<dl id="crypto/subtle"><dt><a href="/pkg/crypto/subtle/">crypto/subtle</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/53021 -->
      TODO: <a href="https://go.dev/issue/53021">https://go.dev/issue/53021</a>: add XORBytes
    </p>

    <p><!-- CL 421435 -->
      TODO: <a href="https://go.dev/cl/421435">https://go.dev/cl/421435</a>: crypto/subtle: add XORBytes; modified api/next/53021.txt
    </p>
  </dd>
</dl><!-- crypto/subtle -->

<dl id="debug/elf"><dt><a href="/pkg/debug/elf/">debug/elf</a></dt>
  <dd>
    <p><!-- CL 420982 -->
      TODO: <a href="https://go.dev/cl/420982">https://go.dev/cl/420982</a>: debug/elf: add new-style LoongArch reloc types; modified api/next/54222.txt
    </p>
  </dd>
</dl><!-- debug/elf -->

<dl id="debug/pe"><dt><a href="/pkg/debug/pe/">debug/pe</a></dt>
  <dd>
    <p><!-- CL 421357 -->
      TODO: <a href="https://go.dev/cl/421357">https://go.dev/cl/421357</a>: debug/pe: add IMAGE_FILE_MACHINE_RISCV{32,64,128}; modified api/next/54251.txt
    </p>
  </dd>
</dl><!-- debug/pe -->

<dl id="encoding/binary"><dt><a href="/pkg/encoding/binary/">encoding/binary</a></dt>
  <dd>
    <p><!-- CL 420274 -->
      TODO: <a href="https://go.dev/cl/420274">https://go.dev/cl/420274</a>: encoding/binary: ReadUvarint return io.ErrUnexpectedEOF when read at least 1 byte
    </p>
  </dd>
</dl><!-- encoding/binary -->

<dl id="encoding/xml"><dt><a href="/pkg/encoding/xml/">encoding/xml</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/53346 -->
      TODO: <a href="https://go.dev/issue/53346">https://go.dev/issue/53346</a>: Add (*Encoder).Close() to check for unclosed elements
    </p>

    <p><!-- CL 424777 -->
      TODO: <a href="https://go.dev/cl/424777">https://go.dev/cl/424777</a>: encoding/xml: add (*Encoder).Close
    </p>
  </dd>
</dl><!-- encoding/xml -->

<dl id="fmt"><dt><a href="/pkg/fmt/">fmt</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/51668 -->
      TODO: <a href="https://go.dev/issue/51668">https://go.dev/issue/51668</a>: add FormatString(State) string
    </p>

    <p><!-- CL 400875 -->
      TODO: <a href="https://go.dev/cl/400875">https://go.dev/cl/400875</a>: fmt: add a function to recover the original format string given a State; modified api/next/51668.txt
    </p>
  </dd>
</dl><!-- fmt -->

<dl id="go/build"><dt><a href="/pkg/go/build/">go/build</a></dt>
  <dd>
    <p><!-- CL 421434 -->
      TODO: <a href="https://go.dev/cl/421434">https://go.dev/cl/421434</a>: go/build: add GO$GOARCH-based ToolTags
    </p>
  </dd>
</dl><!-- go/build -->

<dl id="go/token"><dt><a href="/pkg/go/token/">go/token</a></dt>
  <dd>
    <p><!-- CL 410114 -->
      TODO: <a href="https://go.dev/cl/410114">https://go.dev/cl/410114</a>: go/token: add (*FileSet).RemoveFile(*File) method
    </p>
  </dd>
</dl><!-- go/token -->

<dl id="io"><dt><a href="/pkg/io/">io</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/45899 -->
      TODO: <a href="https://go.dev/issue/45899">https://go.dev/issue/45899</a>: add OffsetWriter, NewOffsetWriter
    </p>

    <p><!-- CL 406776 -->
      TODO: <a href="https://go.dev/cl/406776">https://go.dev/cl/406776</a>: io: add OffsetWriter, NewOffsetWriter; modified api/next/45899.txt
    </p>
  </dd>
</dl><!-- io -->

<dl id="net/http"><dt><a href="/pkg/net/http/">net/http</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/41773 -->
      TODO: <a href="https://go.dev/issue/41773">https://go.dev/issue/41773</a>: add Server.OptionsHandler to allow custom handling of OPTIONS *
    </p>

    <p><!-- CL 356410 -->
      TODO: <a href="https://go.dev/cl/356410">https://go.dev/cl/356410</a>: net/http: add Server.DisableOptionsHandler for custom handling of OPTIONS *; modified api/next/41773.txt
    </p>
  </dd>
</dl><!-- net/http -->

<dl id="net/http/httputil"><dt><a href="/pkg/net/http/httputil/">net/http/httputil</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/50465 -->
      TODO: <a href="https://go.dev/issue/50465">https://go.dev/issue/50465</a>: add X-Forwarded-Proto and X-Forwarded-Host by default
    </p>

    <p><!-- https://go.dev/issue/53002 -->
      TODO: <a href="https://go.dev/issue/53002">https://go.dev/issue/53002</a>: replace Director with Rewrite
    </p>

    <p><!-- CL 407214 -->
      TODO: <a href="https://go.dev/cl/407214">https://go.dev/cl/407214</a>: net/http/httputil: add ReverseProxy.Rewrite; modified api/next/53002.txt
    </p>

    <p><!-- CL 407414 -->
      TODO: <a href="https://go.dev/cl/407414">https://go.dev/cl/407414</a>: net/http/httputil: add X-Forwarded-{Host,Proto} headers in ReverseProxy
    </p>
  </dd>
</dl><!-- net/http/httputil -->

<dl id="os/exec"><dt><a href="/pkg/os/exec/">os/exec</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/50436, CL 401835 -->
      The new <code>Cmd</code> fields <code>Cancel</code> and <code>WaitDelay</code>
      specify the behavior of the <code>Cmd</code> when its associated
      <code>Context</code> is canceled or its process exits with I/O pipes still
      held open by a child process.
    </p>
  </dd>
</dl><!-- os/exec -->

<dl id="strconv"><dt><a href="/pkg/strconv/">strconv</a></dt>
  <dd>
    <p><!-- CL 345488 -->
      TODO: <a href="https://go.dev/cl/345488">https://go.dev/cl/345488</a>: strconv: optimize Parse for []byte arguments
    </p>
  </dd>
</dl><!-- strconv -->

<dl id="strings"><dt><a href="/pkg/strings/">strings</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/42537 -->
      TODO: <a href="https://go.dev/issue/42537">https://go.dev/issue/42537</a>: add CutPrefix and CutSuffix
    </p>

    <p><!-- https://go.dev/issue/45038 -->
      TODO: <a href="https://go.dev/issue/45038">https://go.dev/issue/45038</a>: bytes, strings: add Clone
    </p>
  </dd>
</dl><!-- strings -->

<dl id="syscall"><dt><a href="/pkg/syscall/">syscall</a></dt>
  <dd>
    <p><!-- CL 407574 -->
      TODO: <a href="https://go.dev/cl/407574">https://go.dev/cl/407574</a>: syscall: add new CLONE_ flags for Linux
    </p>
  </dd>
</dl><!-- syscall -->

<dl id="time"><dt><a href="/pkg/time/">time</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/52746 -->
      TODO: <a href="https://go.dev/issue/52746">https://go.dev/issue/52746</a>: add DateTime, DateOnly, TimeOnly format constants
    </p>

    <p><!-- CL 412495 -->
      TODO: <a href="https://go.dev/cl/412495">https://go.dev/cl/412495</a>: time: add DateTime, DateOnly, and TimeOnly
    </p>
  </dd>
</dl><!-- time -->

<dl id="unicode/utf16"><dt><a href="/pkg/unicode/utf16/">unicode/utf16</a></dt>
  <dd>
    <p><!-- https://go.dev/issue/51896 -->
      TODO: <a href="https://go.dev/issue/51896">https://go.dev/issue/51896</a>: add AppendRune
    </p>

    <p><!-- CL 409054 -->
      TODO: <a href="https://go.dev/cl/409054">https://go.dev/cl/409054</a>: unicode/utf16: add AppendRune; modified api/next/51896.txt
    </p>
  </dd>
</dl><!-- unicode/utf16 -->

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