nix-gh/doc/manual/release-notes/rl-2.0.xml

<section xmlns="http://docbook.org/ns/docbook"
      xmlns:xlink="http://www.w3.org/1999/xlink"
      xmlns:xi="http://www.w3.org/2001/XInclude"
      version="5.0"
      xml:id="ssec-relnotes-2.0">

<title>Release 2.0 (2018-02-??)</title>

<para>This release has the following new features:</para>

<itemizedlist>

  <listitem>
    <para>Start of new <command>nix</command> command line
    interface. This is a work in progress and the interface is subject
    to change.</para>

    <itemizedlist>

      <listitem><para>Self-documenting: <option>--help</option> shows
      all available command-line arguments.</para></listitem>

      <listitem><para><option>--help-config</option> shows all
      configuration options.</para></listitem>

      <listitem><para><command>nix build</command>: Replacement for
      <command>nix-build</command>.</para></listitem>

      <listitem><para><command>nix ls-store</command> and <command>nix
      ls-nar</command> allow listing the contents of a store path or
      NAR file.</para></listitem>

      <listitem><para><command>nix cat-store</command> and
      <command>nix cat-nar</command> allow extracting a file from a
      store path or NAR file.</para></listitem>

      <listitem><para><command>nix verify</command> checks whether a
      store path is unmodified and/or is trusted.</para></listitem>

      <listitem><para><command>nix copy-sigs</command> copies
      signatures from one store to another.</para></listitem>

      <listitem><para><command>nix sign-paths</command> signs store
      paths.</para></listitem>

      <listitem><para><command>nix copy</command> copies paths between
      arbitrary Nix stores, generalising
      <command>nix-copy-closure</command> and
      <command>nix-push</command>.</para></listitem>

      <listitem><para><command>nix path-info</command> shows
      information about store paths.</para></listitem>

      <listitem><para><command>nix run</command> starts a shell in
      which the specified packages are available.</para></listitem>

      <listitem><para><command>nix log</command> shows the build log
      of a package or path. If the build log is not available locally,
      it will try to obtain it from a binary cache.</para></listitem>

      <listitem><para><command>nix eval</command> replaces
      <command>nix-instantiate --eval</command>.</para></listitem>

      <listitem><para><command>nix dump-path</command> to get a NAR
      from a store path.</para></listitem>

      <listitem><para><command>nix edit</command> opens the source
      code of a package in an editor.</para></listitem>

      <listitem><para><command>nix search</command> replaces
      <command>nix-env -qa</command>. It searches the available
      packages for occurences of a search string in the attribute
      name, package name or description. It caches available packages
      to speed up searches.</para></listitem>

      <listitem><para><command>nix why-depends</command> (d41c5eb13f4f3a37d80dbc6d3888644170c3b44a).</para></listitem>

      <listitem><para><command>nix show-derivation</command> (e8d6ee7c1b90a2fe6d824f1a875acc56799ae6e2).</para></listitem>

      <listitem><para><command>nix add-to-store</command> (970366266b8df712f5f9cedb45af183ef5a8357f).</para></listitem>

      <listitem><para><command>nix upgrade-nix</command> upgrades Nix
      to the latest stable version. This requires that Nix is
      installed in a profile. (Thus it won’t work on NixOS, or if it’s
      installed outside of the Nix store.)</para></listitem>

      <listitem><para>Progress indicator.</para></listitem>

      <listitem><para>All options are available as flags now
      (b8283773bd64d7da6859ed520ee19867742a03ba).</para></listitem>

    </itemizedlist>

  </listitem>

  <listitem>
    <para>The external program <command>nix-repl</command> has been
    integrated into Nix as <command>nix repl</command>.</para>
  </listitem>

  <listitem>
    <para>If a fixed-output derivation produces a result with an
    incorrect hash, the output path will be moved to the location
    corresponding to the actual hash and registered as valid. Thus, a
    subsequent build of the fixed-output derivation with the correct
    hash is unnecessary.</para>
  </listitem>

  <listitem>
    <para>It is no longer necessary to set the
    <envar>NIX_REMOTE</envar> environment variable if you need to use
    the Nix daemon. Nix will use the daemon automatically if you don’t
    have write access to the Nix database.</para>
  </listitem>

  <listitem>
    <para>The Nix language now supports floating point numbers. They are
    based on regular C++ <literal>float</literal> and compatible with
    existing integers and number-related operations. Export and import to and
    from JSON and XML works, too.</para>
  </listitem>

  <listitem>
    <para><command>nix-shell</command> now sets the
    <varname>IN_NIX_SHELL</varname> environment variable during
    evaluation and in the shell itself. This can be used to perform
    different actions depending on whether you’re in a Nix shell or in
    a regular build. Nixpkgs provides
    <varname>lib.inNixShell</varname> to check this variable during
    evaluation. (bb36a1a3cf3fbe6bc9d0afcc5fa0f928bed03170)</para>
  </listitem>

  <listitem>
    <para>Internal: all <classname>Store</classname> classes are now
    thread-safe. <classname>RemoteStore</classname> supports multiple
    concurrent connections to the daemon. This is primarily useful in
    multi-threaded programs such as
    <command>hydra-queue-runner</command>.</para>
  </listitem>

  <listitem>
    <para>The dependency on Perl has been removed. As a result, some
    (obsolete) programs have been removed: <command>nix-push</command>
    (replaced by <command>nix copy</command>),
    <command>nix-pull</command> (obsoleted by binary caches),
    <command>nix-generate-patches</command>,
    <command>bsdiff</command>, <command>bspatch</command>.</para>
  </listitem>

  <listitem>
    <para>Improved store abstraction. Substituters
    eliminated. BinaryCacheStore, LocalBinaryCacheStore,
    HttpBinaryCacheStore, S3BinaryCacheStore (compile-time
    optional), SSHStore. Add docs + examples?
    </para>
  </listitem>

  <listitem>
    <para>Nix now stores signatures for local store
    paths. Locally-built paths are now signed automatically using the
    secret keys specified by the <option>secret-key-files</option>
    store option.</para>

    <para>In addition, store paths that have been built locally are
    marked as “ultimately trusted”, and content-addressable store
    paths carry a “content-addressability assertion” that allow them
    to be trusted without any signatures.</para>
  </listitem>

  <listitem>
    <para><envar>NIX_PATH</envar> is now lazy, so URIs in the path are
    only downloaded if they are needed for evaluation.</para>
  </listitem>

  <listitem>
    <para>You can now use
    <uri>channel:<replaceable>channel-name</replaceable></uri> as a
    short-hand for
    <uri>https://nixos.org/channels/<replaceable>channel-name</replaceable>/nixexprs.tar.xz</uri>. For
    example, <literal>nix-build channel:nixos-15.09 -A hello</literal>
    will build the GNU Hello package from the
    <literal>nixos-15.09</literal> channel.</para>
  </listitem>

  <listitem>
    <para>When <option>--no-build-output</option> is given, the last
    10 lines of the build log will be shown if a build
    fails.</para>
  </listitem>

  <listitem>
    <para><function>builtins.fetchGit</function>.
    (38539b943a060d9cdfc24d6e5d997c0885b8aa2f)</para>
  </listitem>

  <listitem>
    <para><literal>&lt;nix/fetchurl.nix&gt;</literal> now uses the
    content-addressable tarball cache at
    <uri>http://tarballs.nixos.org/</uri>, just like
    <function>fetchurl</function> in
    Nixpkgs. (f2682e6e18a76ecbfb8a12c17e3a0ca15c084197)</para>
  </listitem>

  <listitem>
    <para>Chroot Nix stores: allow the “physical” location of the Nix
    store (e.g. <filename>/home/alice/nix/store</filename>) to differ
    from its “logical” location (typically
    <filename>/nix/store</filename>). This allows non-root users to
    use Nix while still getting the benefits from prebuilt binaries
    from
    <uri>cache.nixos.org</uri>. (4494000e04122f24558e1436e66d20d89028b4bd,
    3eb621750848e0e6b30e5a79f76afbb096bb6c8a)</para>
  </listitem>

  <listitem>
    <para>On Linux, builds are now executed in a user
    namespace with uid 1000 and gid 100.</para>
  </listitem>

  <listitem>
    <para><function>builtins.fetchurl</function> and
    <function>builtins.fetchTarball</function> now support
    <varname>sha256</varname> and <varname>name</varname>
    attributes.</para>
  </listitem>

  <listitem>
    <para><literal>HttpBinaryCacheStore</literal> (the replacement of
    <command>download-from-binary-cache</command>) now retries
    automatically on certain HTTP error codes.</para>
  </listitem>

  <listitem>
    <para>Derivation attributes can now reference the outputs of the
    derivation using the <function>placeholder</function> builtin
    function. For example, the attribute

<programlisting>
configureFlags = "--prefix=${placeholder "out"} --includedir=${placeholder "dev"}";
</programlisting>

    will cause the <envar>configureFlags</envar> environment variable
    to contain the actual store paths corresponding to the
    <literal>out</literal> and <literal>dev</literal> outputs. TODO:
    add docs.</para>
  </listitem>

  <listitem>
    <para>Support for HTTP/2. This makes binary cache lookups much
    more efficient. (90ad02bf626b885a5dd8967894e2eafc953bdf92)</para>
  </listitem>

  <listitem>
    <para>The <option>build-sandbox-paths</option> configuration
    option can now specify optional paths by appending a
    <literal>?</literal>, e.g. <literal>/dev/nvidiactl?</literal> will
    bind-mount <varname>/dev/nvidiactl</varname> only if it
    exists.</para>
  </listitem>

  <listitem>
    <para>More support for testing build reproducibility: when
    <option>enforce-determinism</option> is set to
    <literal>false</literal>, it’s no longer a fatal error build
    rounds produce different output
    (8bdf83f936adae6f2c907a6d2541e80d4120f051); add a hook to run
    diffoscope when build rounds produce different output
    (9a313469a4bdea2d1e8df24d16289dc2a172a169w).</para>
  </listitem>

  <listitem>
    <para>Kill builds as soon as stdout/stderr is closed. This fixes a
    bug that allowed builds to hang Nix indefinitely (regardless of
    timeouts). (21948deed99a3295e4d5666e027a6ca42dc00b40)</para>
  </listitem>

  <listitem>
    <para>Add support for passing structured data to builders. TODO:
    document. (6de33a9c675b187437a2e1abbcb290981a89ecb1)</para>
  </listitem>

  <listitem>
    <para><varname>exportReferencesGraph</varname>: Export more
    complete info in JSON
    format. (c2b0d8749f7e77afc1c4b3e8dd36b7ee9720af4a)</para>
  </listitem>

  <listitem>
    <para>Support for
    netrc. (e6e74f987f0fa284d220432d426eb965269a97d6,
    302386f775eea309679654e5ea7c972fb6e7b9af)</para>
  </listitem>

  <listitem>
    <para>Support <uri>s3://</uri> URIs in all places where Nix allows
    URIs. (9ff9c3f2f80ba4108e9c945bbfda2c64735f987b)</para>
  </listitem>

  <listitem>
    <para>The <option>build-max-jobs</option> option can be set to
    <literal>auto</literal> to use the number of CPUs in the
    system. (7251d048fa812d2551b7003bc9f13a8f5d4c95a5)</para>
  </listitem>

  <listitem>
    <para>Add support for Brotli compression.
    <uri>cache.nixos.org</uri> compresses build logs using
    Brotli.</para>
  </listitem>

  <listitem>
    <para>Substitutions from binary caches now require signatures by
    default. This was already the case on
    NixOS. (ecbc3fedd3d5bdc5a0e1a0a51b29062f2874ac8b)</para>
  </listitem>

  <listitem>
    <para><command>nix-env</command> now ignores packages with bad
    derivation names (in particular those starting with a digit or
    containing a
    dot). (b0cb11722626e906a73f10dd9a0c9eea29faf43a)</para>
  </listitem>

  <listitem>
    <para>Renamed various configuration options. (TODO: in progress)</para>
  </listitem>

  <listitem>
    <para>Remote machines can now be specified on the command
    line. TODO:
    document. (1a68710d4dff609bbaf61db3e17a2573f0aadf17)</para>
  </listitem>

  <listitem>
    <para>In Linux sandbox builds, we now use
    <filename>/build</filename> instead of <filename>/tmp</filename>
    as the temporary build directory. This fixes potential security
    problems when a build accidentally stores its
    <envar>TMPDIR</envar> in some critical place, such as an
    RPATH. (eba840c8a13b465ace90172ff76a0db2899ab11b)</para>
  </listitem>

  <listitem>
    <para>In Linux sandbox builds, we now provide a default
    <filename>/bin/sh</filename> (namely <filename>ash</filename> from
    BusyBox). (a2d92bb20e82a0957067ede60e91fab256948b41)</para>
  </listitem>

  <listitem>
    <para>Make all configuration options available as command line
    flags (b8283773bd64d7da6859ed520ee19867742a03ba).</para>
  </listitem>

  <listitem>
    <para>Support base-64
    hashes. (c0015e87af70f539f24d2aa2bc224a9d8b84276b)</para>
  </listitem>

  <listitem>
    <para><command>nix-shell</command> now uses
    <varname>bashInteractive</varname> from Nixpkgs, rather than the
    <command>bash</command> command that happens to be in the caller’s
    <envar>PATH</envar>. This is especially important on macOS where
    the <command>bash</command> provided by the system is seriously
    outdated and cannot execute <literal>stdenv</literal>’s setup
    script.</para>
  </listitem>

  <listitem>
    <para>New builtin functions: <function>builtins.split</function>
    (b8867a0239b1930a16f9ef3f7f3e864b01416dff),
    <function>builtins.partition</function>.</para>
  </listitem>

  <listitem>
    <para>Automatic garbage collection.</para>
  </listitem>

  <listitem>
    <para><command>nix-store -q --roots</command> and
    <command>nix-store --gc --print-roots</command> now show temporary
    and in-memory roots.</para>
  </listitem>

  <listitem>
    <para>Builders can now communicate what build phase they are in by
    writing messages to the file descriptor specified in
    <envar>NIX_LOG_FD</envar>. (88e6bb76de5564b3217be9688677d1c89101b2a3)
    </para>
  </listitem>

</itemizedlist>

<para>Some features were removed:</para>

<itemizedlist>

  <listitem>
    <para>“Nested” log output. As a result,
    <command>nix-log2xml</command> was also removed.</para>
  </listitem>

  <listitem>
    <para>OpenSSL-based signing. (f435f8247553656774dd1b2c88e9de5d59cab203)</para>
  </listitem>

  <listitem>
    <para>Caching of failed
    builds. (8cffec84859cec8b610a2a22ab0c4d462a9351ff)</para>
  </listitem>

  <listitem>
    <para><filename>nix-mode.el</filename> has been removed from
    Nix. It is now a separate repository in
    <uri>https://github.com/NixOS/nix-mode</uri> and can be installed
    through the MELPA package repository.</para>
  </listitem>

  <listitem>
    <para>In restricted evaluation mode
    (<option>--restrict-eval</option>), builtin functions that
    download from the network (such as <function>fetchGit</function>)
    are permitted to fetch underneath the list of URI prefixes
    specified in the option <option>allowed-uris</option>.</para>
  </listitem>

</itemizedlist>

<para>This release has contributions from TBD.</para>

</section>