<article xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-relnotes"> <title>Nix Release Notes</title> <!--==================================================================--> <section xml:id="ssec-relnotes-0.16"><title>Release 0.16 (August 17, 2010)</title> <para>This release has the following improvements:</para> <itemizedlist> <listitem> <para>The Nix expression evaluator is now much faster in most cases: typically, <link xlink:href="http://www.mail-archive.com/nix-dev@cs.uu.nl/msg04113.html">3 to 8 times compared to the old implementation</link>. It also uses less memory. It no longer depends on the ATerm library.</para> </listitem> <listitem> <para> Support for configurable parallelism inside builders. Build scripts have always had the ability to perform multiple build actions in parallel (for instance, by running <command>make -j 2</command>), but this was not desirable because the number of actions to be performed in parallel was not configurable. Nix now has an option <option>--cores <replaceable>N</replaceable></option> as well as a configuration setting <varname>build-cores = <replaceable>N</replaceable></varname> that causes the environment variable <envar>NIX_BUILD_CORES</envar> to be set to <replaceable>N</replaceable> when the builder is invoked. The builder can use this at its discretion to perform a parallel build, e.g., by calling <command>make -j <replaceable>N</replaceable></command>. In Nixpkgs, this can be enabled on a per-package basis by setting the derivation attribute <varname>enableParallelBuilding</varname> to <literal>true</literal>. </para> </listitem> <listitem> <para><command>nix-store -q</command> now supports XML output through the <option>--xml</option> flag.</para> </listitem> <listitem> <para>Several bug fixes.</para> </listitem> </itemizedlist> </section> <!--==================================================================--> <section xml:id="ssec-relnotes-0.15"><title>Release 0.15 (March 17, 2010)</title> <para>This is a bug-fix release. Among other things, it fixes building on Mac OS X (Snow Leopard), and improves the contents of <filename>/etc/passwd</filename> and <filename>/etc/group</filename> in <literal>chroot</literal> builds.</para> </section> <!--==================================================================--> <section xml:id="ssec-relnotes-0.14"><title>Release 0.14 (February 4, 2010)</title> <para>This release has the following improvements:</para> <itemizedlist> <listitem> <para>The garbage collector now starts deleting garbage much faster than before. It no longer determines liveness of all paths in the store, but does so on demand.</para> </listitem> <listitem> <para>Added a new operation, <command>nix-store --query --roots</command>, that shows the garbage collector roots that directly or indirectly point to the given store paths.</para> </listitem> <listitem> <para>Removed support for converting Berkeley DB-based Nix databases to the new schema.</para> </listitem> <listitem> <para>Removed the <option>--use-atime</option> and <option>--max-atime</option> garbage collector options. They were not very useful in practice.</para> </listitem> <listitem> <para>On Windows, Nix now requires Cygwin 1.7.x.</para> </listitem> <listitem> <para>A few bug fixes.</para> </listitem> </itemizedlist> </section> <!--==================================================================--> <section xml:id="ssec-relnotes-0.13"><title>Release 0.13 (November 5, 2009)</title> <para>This is primarily a bug fix release. It has some new features:</para> <itemizedlist> <listitem> <para>Syntactic sugar for writing nested attribute sets. Instead of <programlisting> { foo = { bar = 123; xyzzy = true; }; a = { b = { c = "d"; }; }; } </programlisting> you can write <programlisting> { foo.bar = 123; foo.xyzzy = true; a.b.c = "d"; } </programlisting> This is useful, for instance, in NixOS configuration files.</para> </listitem> <listitem> <para>Support for Nix channels generated by Hydra, the Nix-based continuous build system. (Hydra generates NAR archives on the fly, so the size and hash of these archives isn’t known in advance.)</para> </listitem> <listitem> <para>Support <literal>i686-linux</literal> builds directly on <literal>x86_64-linux</literal> Nix installations. This is implemented using the <function>personality()</function> syscall, which causes <command>uname</command> to return <literal>i686</literal> in child processes.</para> </listitem> <listitem> <para>Various improvements to the <literal>chroot</literal> support. Building in a <literal>chroot</literal> works quite well now.</para> </listitem> <listitem> <para>Nix no longer blocks if it tries to build a path and another process is already building the same path. Instead it tries to build another buildable path first. This improves parallelism.</para> </listitem> <listitem> <para>Support for large (> 4 GiB) files in NAR archives.</para> </listitem> <listitem> <para>Various (performance) improvements to the remote build mechanism.</para> </listitem> <listitem> <para>New primops: <varname>builtins.addErrorContext</varname> (to add a string to stack traces — useful for debugging), <varname>builtins.isBool</varname>, <varname>builtins.isString</varname>, <varname>builtins.isInt</varname>, <varname>builtins.intersectAttrs</varname>.</para> </listitem> <listitem> <para>OpenSolaris support (Sander van der Burg).</para> </listitem> <listitem> <para>Stack traces are no longer displayed unless the <option>--show-trace</option> option is used.</para> </listitem> <listitem> <para>The scoping rules for <literal>inherit (<replaceable>e</replaceable>) ...</literal> in recursive attribute sets have changed. The expression <replaceable>e</replaceable> can now refer to the attributes defined in the containing set.</para> </listitem> </itemizedlist> </section> <!--==================================================================--> <section xml:id="ssec-relnotes-0.12"><title>Release 0.12 (November 20, 2008)</title> <itemizedlist> <listitem> <para>Nix no longer uses Berkeley DB to store Nix store metadata. The principal advantages of the new storage scheme are: it works properly over decent implementations of NFS (allowing Nix stores to be shared between multiple machines); no recovery is needed when a Nix process crashes; no write access is needed for read-only operations; no more running out of Berkeley DB locks on certain operations.</para> <para>You still need to compile Nix with Berkeley DB support if you want Nix to automatically convert your old Nix store to the new schema. If you don’t need this, you can build Nix with the <filename>configure</filename> option <option>--disable-old-db-compat</option>.</para> <para>After the automatic conversion to the new schema, you can delete the old Berkeley DB files: <screen> $ cd /nix/var/nix/db $ rm __db* log.* derivers references referrers reserved validpaths DB_CONFIG</screen> The new metadata is stored in the directories <filename>/nix/var/nix/db/info</filename> and <filename>/nix/var/nix/db/referrer</filename>. Though the metadata is stored in human-readable plain-text files, they are not intended to be human-editable, as Nix is rather strict about the format.</para> <para>The new storage schema may or may not require less disk space than the Berkeley DB environment, mostly depending on the cluster size of your file system. With 1 KiB clusters (which seems to be the <literal>ext3</literal> default nowadays) it usually takes up much less space.</para> </listitem> <listitem><para>There is a new substituter that copies paths directly from other (remote) Nix stores mounted somewhere in the filesystem. For instance, you can speed up an installation by mounting some remote Nix store that already has the packages in question via NFS or <literal>sshfs</literal>. The environment variable <envar>NIX_OTHER_STORES</envar> specifies the locations of the remote Nix directories, e.g. <literal>/mnt/remote-fs/nix</literal>.</para></listitem> <listitem><para>New <command>nix-store</command> operations <option>--dump-db</option> and <option>--load-db</option> to dump and reload the Nix database.</para></listitem> <listitem><para>The garbage collector has a number of new options to allow only some of the garbage to be deleted. The option <option>--max-freed <replaceable>N</replaceable></option> tells the collector to stop after at least <replaceable>N</replaceable> bytes have been deleted. The option <option>--max-links <replaceable>N</replaceable></option> tells it to stop after the link count on <filename>/nix/store</filename> has dropped below <replaceable>N</replaceable>. This is useful for very large Nix stores on filesystems with a 32000 subdirectories limit (like <literal>ext3</literal>). The option <option>--use-atime</option> causes store paths to be deleted in order of ascending last access time. This allows non-recently used stuff to be deleted. The option <option>--max-atime <replaceable>time</replaceable></option> specifies an upper limit to the last accessed time of paths that may be deleted. For instance, <screen> $ nix-store --gc -v --max-atime $(date +%s -d "2 months ago")</screen> deletes everything that hasn’t been accessed in two months.</para></listitem> <listitem><para><command>nix-env</command> now uses optimistic profile locking when performing an operation like installing or upgrading, instead of setting an exclusive lock on the profile. This allows multiple <command>nix-env -i / -u / -e</command> operations on the same profile in parallel. If a <command>nix-env</command> operation sees at the end that the profile was changed in the meantime by another process, it will just restart. This is generally cheap because the build results are still in the Nix store.</para></listitem> <listitem><para>The option <option>--dry-run</option> is now supported by <command>nix-store -r</command> and <command>nix-build</command>.</para></listitem> <listitem><para>The information previously shown by <option>--dry-run</option> (i.e., which derivations will be built and which paths will be substituted) is now always shown by <command>nix-env</command>, <command>nix-store -r</command> and <command>nix-build</command>. The total download size of substitutable paths is now also shown. For instance, a build will show something like <screen> the following derivations will be built: /nix/store/129sbxnk5n466zg6r1qmq1xjv9zymyy7-activate-configuration.sh.drv /nix/store/7mzy971rdm8l566ch8hgxaf89x7lr7ik-upstart-jobs.drv ... the following paths will be downloaded/copied (30.02 MiB): /nix/store/4m8pvgy2dcjgppf5b4cj5l6wyshjhalj-samba-3.2.4 /nix/store/7h1kwcj29ip8vk26rhmx6bfjraxp0g4l-libunwind-0.98.6 ...</screen> </para></listitem> <listitem><para>Language features: <itemizedlist> <listitem><para>@-patterns as in Haskell. For instance, in a function definition <programlisting>f = args @ {x, y, z}: <replaceable>...</replaceable>;</programlisting> <varname>args</varname> refers to the argument as a whole, which is further pattern-matched against the attribute set pattern <literal>{x, y, z}</literal>.</para></listitem> <listitem><para>“<literal>...</literal>” (ellipsis) patterns. An attribute set pattern can now say <literal>...</literal> at the end of the attribute name list to specify that the function takes <emphasis>at least</emphasis> the listed attributes, while ignoring additional attributes. For instance, <programlisting>{stdenv, fetchurl, fuse, ...}: <replaceable>...</replaceable></programlisting> defines a function that accepts any attribute set that includes at least the three listed attributes.</para></listitem> <listitem><para>New primops: <varname>builtins.parseDrvName</varname> (split a package name string like <literal>"nix-0.12pre12876"</literal> into its name and version components, e.g. <literal>"nix"</literal> and <literal>"0.12pre12876"</literal>), <varname>builtins.compareVersions</varname> (compare two version strings using the same algorithm that <command>nix-env</command> uses), <varname>builtins.length</varname> (efficiently compute the length of a list), <varname>builtins.mul</varname> (integer multiplication), <varname>builtins.div</varname> (integer division). <!-- <varname>builtins.genericClosure</varname> --> </para></listitem> </itemizedlist> </para></listitem> <listitem><para><command>nix-prefetch-url</command> now supports <literal>mirror://</literal> URLs, provided that the environment variable <envar>NIXPKGS_ALL</envar> points at a Nixpkgs tree.</para></listitem> <listitem><para>Removed the commands <command>nix-pack-closure</command> and <command>nix-unpack-closure</command>. You can do almost the same thing but much more efficiently by doing <literal>nix-store --export $(nix-store -qR <replaceable>paths</replaceable>) > closure</literal> and <literal>nix-store --import < closure</literal>.</para></listitem> <listitem><para>Lots of bug fixes, including a big performance bug in the handling of <literal>with</literal>-expressions.</para></listitem> </itemizedlist> </section> <!--==================================================================--> <section xml:id="ssec-relnotes-0.11"><title>Release 0.11 (December 31, 2007)</title> <para>Nix 0.11 has many improvements over the previous stable release. The most important improvement is secure multi-user support. It also features many usability enhancements and language extensions, many of them prompted by NixOS, the purely functional Linux distribution based on Nix. Here is an (incomplete) list:</para> <itemizedlist> <listitem><para>Secure multi-user support. A single Nix store can now be shared between multiple (possible untrusted) users. This is an important feature for NixOS, where it allows non-root users to install software. The old setuid method for sharing a store between multiple users has been removed. Details for setting up a multi-user store can be found in the manual.</para></listitem> <listitem><para>The new command <command>nix-copy-closure</command> gives you an easy and efficient way to exchange software between machines. It copies the missing parts of the closure of a set of store path to or from a remote machine via <command>ssh</command>.</para></listitem> <listitem><para>A new kind of string literal: strings between double single-quotes (<literal>''</literal>) have indentation “intelligently” removed. This allows large strings (such as shell scripts or configuration file fragments in NixOS) to cleanly follow the indentation of the surrounding expression. It also requires much less escaping, since <literal>''</literal> is less common in most languages than <literal>"</literal>.</para></listitem> <listitem><para><command>nix-env</command> <option>--set</option> modifies the current generation of a profile so that it contains exactly the specified derivation, and nothing else. For example, <literal>nix-env -p /nix/var/nix/profiles/browser --set firefox</literal> lets the profile named <filename>browser</filename> contain just Firefox.</para></listitem> <listitem><para><command>nix-env</command> now maintains meta-information about installed packages in profiles. The meta-information is the contents of the <varname>meta</varname> attribute of derivations, such as <varname>description</varname> or <varname>homepage</varname>. The command <literal>nix-env -q --xml --meta</literal> shows all meta-information.</para></listitem> <listitem><para><command>nix-env</command> now uses the <varname>meta.priority</varname> attribute of derivations to resolve filename collisions between packages. Lower priority values denote a higher priority. For instance, the GCC wrapper package and the Binutils package in Nixpkgs both have a file <filename>bin/ld</filename>, so previously if you tried to install both you would get a collision. Now, on the other hand, the GCC wrapper declares a higher priority than Binutils, so the former’s <filename>bin/ld</filename> is symlinked in the user environment.</para></listitem> <listitem><para><command>nix-env -i / -u</command>: instead of breaking package ties by version, break them by priority and version number. That is, if there are multiple packages with the same name, then pick the package with the highest priority, and only use the version if there are multiple packages with the same priority.</para> <para>This makes it possible to mark specific versions/variant in Nixpkgs more or less desirable than others. A typical example would be a beta version of some package (e.g., <literal>gcc-4.2.0rc1</literal>) which should not be installed even though it is the highest version, except when it is explicitly selected (e.g., <literal>nix-env -i gcc-4.2.0rc1</literal>).</para></listitem> <listitem><para><command>nix-env --set-flag</command> allows meta attributes of installed packages to be modified. There are several attributes that can be usefully modified, because they affect the behaviour of <command>nix-env</command> or the user environment build script: <itemizedlist> <listitem><para><varname>meta.priority</varname> can be changed to resolve filename clashes (see above).</para></listitem> <listitem><para><varname>meta.keep</varname> can be set to <literal>true</literal> to prevent the package from being upgraded or replaced. Useful if you want to hang on to an older version of a package.</para></listitem> <listitem><para><varname>meta.active</varname> can be set to <literal>false</literal> to “disable” the package. That is, no symlinks will be generated to the files of the package, but it remains part of the profile (so it won’t be garbage-collected). Set it back to <literal>true</literal> to re-enable the package.</para></listitem> </itemizedlist> </para></listitem> <listitem><para><command>nix-env -q</command> now has a flag <option>--prebuilt-only</option> (<option>-b</option>) that causes <command>nix-env</command> to show only those derivations whose output is already in the Nix store or that can be substituted (i.e., downloaded from somewhere). In other words, it shows the packages that can be installed “quickly”, i.e., don’t need to be built from source. The <option>-b</option> flag is also available in <command>nix-env -i</command> and <command>nix-env -u</command> to filter out derivations for which no pre-built binary is available.</para></listitem> <listitem><para>The new option <option>--argstr</option> (in <command>nix-env</command>, <command>nix-instantiate</command> and <command>nix-build</command>) is like <option>--arg</option>, except that the value is a string. For example, <literal>--argstr system i686-linux</literal> is equivalent to <literal>--arg system \"i686-linux\"</literal> (note that <option>--argstr</option> prevents annoying quoting around shell arguments).</para></listitem> <listitem><para><command>nix-store</command> has a new operation <option>--read-log</option> (<option>-l</option>) <parameter>paths</parameter> that shows the build log of the given paths.</para></listitem> <!-- <listitem><para>TODO: semantic cleanups of string concatenation etc. (mostly in r6740).</para></listitem> --> <listitem><para>Nix now uses Berkeley DB 4.5. The database is upgraded automatically, but you should be careful not to use old versions of Nix that still use Berkeley DB 4.4.</para></listitem> <!-- foo <listitem><para>TODO: option <option>- -reregister</option> in <command>nix-store - -register-validity</command>.</para></listitem> --> <listitem><para>The option <option>--max-silent-time</option> (corresponding to the configuration setting <literal>build-max-silent-time</literal>) allows you to set a timeout on builds — if a build produces no output on <literal>stdout</literal> or <literal>stderr</literal> for the given number of seconds, it is terminated. This is useful for recovering automatically from builds that are stuck in an infinite loop.</para></listitem> <listitem><para><command>nix-channel</command>: each subscribed channel is its own attribute in the top-level expression generated for the channel. This allows disambiguation (e.g. <literal>nix-env -i -A nixpkgs_unstable.firefox</literal>).</para></listitem> <listitem><para>The substitutes table has been removed from the database. This makes operations such as <command>nix-pull</command> and <command>nix-channel --update</command> much, much faster.</para></listitem> <listitem><para><command>nix-pull</command> now supports bzip2-compressed manifests. This speeds up channels.</para></listitem> <listitem><para><command>nix-prefetch-url</command> now has a limited form of caching. This is used by <command>nix-channel</command> to prevent unnecessary downloads when the channel hasn’t changed.</para></listitem> <listitem><para><command>nix-prefetch-url</command> now by default computes the SHA-256 hash of the file instead of the MD5 hash. In calls to <function>fetchurl</function> you should pass the <literal>sha256</literal> attribute instead of <literal>md5</literal>. You can pass either a hexadecimal or a base-32 encoding of the hash.</para></listitem> <listitem><para>Nix can now perform builds in an automatically generated “chroot”. This prevents a builder from accessing stuff outside of the Nix store, and thus helps ensure purity. This is an experimental feature.</para></listitem> <listitem><para>The new command <command>nix-store --optimise</command> reduces Nix store disk space usage by finding identical files in the store and hard-linking them to each other. It typically reduces the size of the store by something like 25-35%.</para></listitem> <listitem><para><filename>~/.nix-defexpr</filename> can now be a directory, in which case the Nix expressions in that directory are combined into an attribute set, with the file names used as the names of the attributes. The command <command>nix-env --import</command> (which set the <filename>~/.nix-defexpr</filename> symlink) is removed.</para></listitem> <listitem><para>Derivations can specify the new special attribute <varname>allowedReferences</varname> to enforce that the references in the output of a derivation are a subset of a declared set of paths. For example, if <varname>allowedReferences</varname> is an empty list, then the output must not have any references. This is used in NixOS to check that generated files such as initial ramdisks for booting Linux don’t have any dependencies.</para></listitem> <listitem><para>The new attribute <varname>exportReferencesGraph</varname> allows builders access to the references graph of their inputs. This is used in NixOS for tasks such as generating ISO-9660 images that contain a Nix store populated with the closure of certain paths.</para></listitem> <listitem><para>Fixed-output derivations (like <function>fetchurl</function>) can define the attribute <varname>impureEnvVars</varname> to allow external environment variables to be passed to builders. This is used in Nixpkgs to support proxy configuration, among other things.</para></listitem> <listitem><para>Several new built-in functions: <function>builtins.attrNames</function>, <function>builtins.filterSource</function>, <function>builtins.isAttrs</function>, <function>builtins.isFunction</function>, <function>builtins.listToAttrs</function>, <function>builtins.stringLength</function>, <function>builtins.sub</function>, <function>builtins.substring</function>, <function>throw</function>, <function>builtins.trace</function>, <function>builtins.readFile</function>.</para></listitem> </itemizedlist> </section> <!--==================================================================--> <section><title>Release 0.10.1 (October 11, 2006)</title> <para>This release fixes two somewhat obscure bugs that occur when evaluating Nix expressions that are stored inside the Nix store (<literal>NIX-67</literal>). These do not affect most users.</para> </section> <!--==================================================================--> <section><title>Release 0.10 (October 6, 2006)</title> <note><para>This version of Nix uses Berkeley DB 4.4 instead of 4.3. The database is upgraded automatically, but you should be careful not to use old versions of Nix that still use Berkeley DB 4.3. In particular, if you use a Nix installed through Nix, you should run <screen> $ nix-store --clear-substitutes</screen> first.</para></note> <warning><para>Also, the database schema has changed slighted to fix a performance issue (see below). When you run any Nix 0.10 command for the first time, the database will be upgraded automatically. This is irreversible.</para></warning> <itemizedlist> <!-- Usability / features --> <listitem><para><command>nix-env</command> usability improvements: <itemizedlist> <listitem><para>An option <option>--compare-versions</option> (or <option>-c</option>) has been added to <command>nix-env --query</command> to allow you to compare installed versions of packages to available versions, or vice versa. An easy way to see if you are up to date with what’s in your subscribed channels is <literal>nix-env -qc \*</literal>.</para></listitem> <listitem><para><literal>nix-env --query</literal> now takes as arguments a list of package names about which to show information, just like <option>--install</option>, etc.: for example, <literal>nix-env -q gcc</literal>. Note that to show all derivations, you need to specify <literal>\*</literal>.</para></listitem> <listitem><para><literal>nix-env -i <replaceable>pkgname</replaceable></literal> will now install the highest available version of <replaceable>pkgname</replaceable>, rather than installing all available versions (which would probably give collisions) (<literal>NIX-31</literal>).</para></listitem> <listitem><para><literal>nix-env (-i|-u) --dry-run</literal> now shows exactly which missing paths will be built or substituted.</para></listitem> <listitem><para><literal>nix-env -qa --description</literal> shows human-readable descriptions of packages, provided that they have a <literal>meta.description</literal> attribute (which most packages in Nixpkgs don’t have yet).</para></listitem> </itemizedlist> </para></listitem> <listitem><para>New language features: <itemizedlist> <listitem><para>Reference scanning (which happens after each build) is much faster and takes a constant amount of memory.</para></listitem> <listitem><para>String interpolation. Expressions like <programlisting> "--with-freetype2-library=" + freetype + "/lib"</programlisting> can now be written as <programlisting> "--with-freetype2-library=${freetype}/lib"</programlisting> You can write arbitrary expressions within <literal>${<replaceable>...</replaceable>}</literal>, not just identifiers.</para></listitem> <listitem><para>Multi-line string literals.</para></listitem> <listitem><para>String concatenations can now involve derivations, as in the example <code>"--with-freetype2-library=" + freetype + "/lib"</code>. This was not previously possible because we need to register that a derivation that uses such a string is dependent on <literal>freetype</literal>. The evaluator now properly propagates this information. Consequently, the subpath operator (<literal>~</literal>) has been deprecated.</para></listitem> <listitem><para>Default values of function arguments can now refer to other function arguments; that is, all arguments are in scope in the default values (<literal>NIX-45</literal>).</para></listitem> <!-- <listitem><para>TODO: domain checks (r5895).</para></listitem> --> <listitem><para>Lots of new built-in primitives, such as functions for list manipulation and integer arithmetic. See the manual for a complete list. All primops are now available in the set <varname>builtins</varname>, allowing one to test for the availability of primop in a backwards-compatible way.</para></listitem> <listitem><para>Real let-expressions: <literal>let x = ...; ... z = ...; in ...</literal>.</para></listitem> </itemizedlist> </para></listitem> <listitem><para>New commands <command>nix-pack-closure</command> and <command>nix-unpack-closure</command> than can be used to easily transfer a store path with all its dependencies to another machine. Very convenient whenever you have some package on your machine and you want to copy it somewhere else.</para></listitem> <listitem><para>XML support: <itemizedlist> <listitem><para><literal>nix-env -q --xml</literal> prints the installed or available packages in an XML representation for easy processing by other tools.</para></listitem> <listitem><para><literal>nix-instantiate --eval-only --xml</literal> prints an XML representation of the resulting term. (The new flag <option>--strict</option> forces ‘deep’ evaluation of the result, i.e., list elements and attributes are evaluated recursively.)</para></listitem> <listitem><para>In Nix expressions, the primop <function>builtins.toXML</function> converts a term to an XML representation. This is primarily useful for passing structured information to builders.</para></listitem> </itemizedlist> </para></listitem> <listitem><para>You can now unambigously specify which derivation to build or install in <command>nix-env</command>, <command>nix-instantiate</command> and <command>nix-build</command> using the <option>--attr</option> / <option>-A</option> flags, which takes an attribute name as argument. (Unlike symbolic package names such as <literal>subversion-1.4.0</literal>, attribute names in an attribute set are unique.) For instance, a quick way to perform a test build of a package in Nixpkgs is <literal>nix-build pkgs/top-level/all-packages.nix -A <replaceable>foo</replaceable></literal>. <literal>nix-env -q --attr</literal> shows the attribute names corresponding to each derivation.</para></listitem> <listitem><para>If the top-level Nix expression used by <command>nix-env</command>, <command>nix-instantiate</command> or <command>nix-build</command> evaluates to a function whose arguments all have default values, the function will be called automatically. Also, the new command-line switch <option>--arg <replaceable>name</replaceable> <replaceable>value</replaceable></option> can be used to specify function arguments on the command line.</para></listitem> <listitem><para><literal>nix-install-package --url <replaceable>URL</replaceable></literal> allows a package to be installed directly from the given URL.</para></listitem> <listitem><para>Nix now works behind an HTTP proxy server; just set the standard environment variables <envar>http_proxy</envar>, <envar>https_proxy</envar>, <envar>ftp_proxy</envar> or <envar>all_proxy</envar> appropriately. Functions such as <function>fetchurl</function> in Nixpkgs also respect these variables.</para></listitem> <listitem><para><literal>nix-build -o <replaceable>symlink</replaceable></literal> allows the symlink to the build result to be named something other than <literal>result</literal>.</para></listitem> <!-- Stability / performance / etc. --> <listitem><para>Platform support: <itemizedlist> <listitem><para>Support for 64-bit platforms, provided a <link xlink:href="http://bugzilla.sen.cwi.nl:8080/show_bug.cgi?id=606">suitably patched ATerm library</link> is used. Also, files larger than 2 GiB are now supported.</para></listitem> <listitem><para>Added support for Cygwin (Windows, <literal>i686-cygwin</literal>), Mac OS X on Intel (<literal>i686-darwin</literal>) and Linux on PowerPC (<literal>powerpc-linux</literal>).</para></listitem> <listitem><para>Users of SMP and multicore machines will appreciate that the number of builds to be performed in parallel can now be specified in the configuration file in the <literal>build-max-jobs</literal> setting.</para></listitem> </itemizedlist> </para></listitem> <listitem><para>Garbage collector improvements: <itemizedlist> <listitem><para>Open files (such as running programs) are now used as roots of the garbage collector. This prevents programs that have been uninstalled from being garbage collected while they are still running. The script that detects these additional runtime roots (<filename>find-runtime-roots.pl</filename>) is inherently system-specific, but it should work on Linux and on all platforms that have the <command>lsof</command> utility.</para></listitem> <listitem><para><literal>nix-store --gc</literal> (a.k.a. <command>nix-collect-garbage</command>) prints out the number of bytes freed on standard output. <literal>nix-store --gc --print-dead</literal> shows how many bytes would be freed by an actual garbage collection.</para></listitem> <listitem><para><literal>nix-collect-garbage -d</literal> removes all old generations of <emphasis>all</emphasis> profiles before calling the actual garbage collector (<literal>nix-store --gc</literal>). This is an easy way to get rid of all old packages in the Nix store.</para></listitem> <listitem><para><command>nix-store</command> now has an operation <option>--delete</option> to delete specific paths from the Nix store. It won’t delete reachable (non-garbage) paths unless <option>--ignore-liveness</option> is specified.</para></listitem> </itemizedlist> </para></listitem> <listitem><para>Berkeley DB 4.4’s process registry feature is used to recover from crashed Nix processes.</para></listitem> <!-- <listitem><para>TODO: shared stores.</para></listitem> --> <listitem><para>A performance issue has been fixed with the <literal>referer</literal> table, which stores the inverse of the <literal>references</literal> table (i.e., it tells you what store paths refer to a given path). Maintaining this table could take a quadratic amount of time, as well as a quadratic amount of Berkeley DB log file space (in particular when running the garbage collector) (<literal>NIX-23</literal>).</para></listitem> <listitem><para>Nix now catches the <literal>TERM</literal> and <literal>HUP</literal> signals in addition to the <literal>INT</literal> signal. So you can now do a <literal>killall nix-store</literal> without triggering a database recovery.</para></listitem> <listitem><para><command>bsdiff</command> updated to version 4.3.</para></listitem> <listitem><para>Substantial performance improvements in expression evaluation and <literal>nix-env -qa</literal>, all thanks to <link xlink:href="http://valgrind.org/">Valgrind</link>. Memory use has been reduced by a factor 8 or so. Big speedup by memoisation of path hashing.</para></listitem> <listitem><para>Lots of bug fixes, notably: <itemizedlist> <listitem><para>Make sure that the garbage collector can run succesfully when the disk is full (<literal>NIX-18</literal>).</para></listitem> <listitem><para><command>nix-env</command> now locks the profile to prevent races between concurrent <command>nix-env</command> operations on the same profile (<literal>NIX-7</literal>).</para></listitem> <listitem><para>Removed misleading messages from <literal>nix-env -i</literal> (e.g., <literal>installing `foo'</literal> followed by <literal>uninstalling `foo'</literal>) (<literal>NIX-17</literal>).</para></listitem> </itemizedlist> </para></listitem> <listitem><para>Nix source distributions are a lot smaller now since we no longer include a full copy of the Berkeley DB source distribution (but only the bits we need).</para></listitem> <listitem><para>Header files are now installed so that external programs can use the Nix libraries.</para></listitem> </itemizedlist> </section> <!--==================================================================--> <section><title>Release 0.9.2 (September 21, 2005)</title> <para>This bug fix release fixes two problems on Mac OS X: <itemizedlist> <listitem><para>If Nix was linked against statically linked versions of the ATerm or Berkeley DB library, there would be dynamic link errors at runtime.</para></listitem> <listitem><para><command>nix-pull</command> and <command>nix-push</command> intermittently failed due to race conditions involving pipes and child processes with error messages such as <literal>open2: open(GLOB(0x180b2e4), >&=9) failed: Bad file descriptor at /nix/bin/nix-pull line 77</literal> (issue <literal>NIX-14</literal>).</para></listitem> </itemizedlist> </para> </section> <!--==================================================================--> <section><title>Release 0.9.1 (September 20, 2005)</title> <para>This bug fix release addresses a problem with the ATerm library when the <option>--with-aterm</option> flag in <command>configure</command> was <emphasis>not</emphasis> used.</para> </section> <!--==================================================================--> <section><title>Release 0.9 (September 16, 2005)</title> <para>NOTE: this version of Nix uses Berkeley DB 4.3 instead of 4.2. The database is upgraded automatically, but you should be careful not to use old versions of Nix that still use Berkeley DB 4.2. In particular, if you use a Nix installed through Nix, you should run <screen> $ nix-store --clear-substitutes</screen> first.</para> <itemizedlist> <listitem><para>Unpacking of patch sequences is much faster now since we no longer do redundant unpacking and repacking of intermediate paths.</para></listitem> <listitem><para>Nix now uses Berkeley DB 4.3.</para></listitem> <listitem><para>The <function>derivation</function> primitive is lazier. Attributes of dependent derivations can mutually refer to each other (as long as there are no data dependencies on the <varname>outPath</varname> and <varname>drvPath</varname> attributes computed by <function>derivation</function>).</para> <para>For example, the expression <literal>derivation attrs</literal> now evaluates to (essentially) <programlisting> attrs // { type = "derivation"; outPath = derivation! attrs; drvPath = derivation! attrs; }</programlisting> where <function>derivation!</function> is a primop that does the actual derivation instantiation (i.e., it does what <function>derivation</function> used to do). The advantage is that it allows commands such as <command>nix-env -qa</command> and <command>nix-env -i</command> to be much faster since they no longer need to instantiate all derivations, just the <varname>name</varname> attribute.</para> <para>Also, it allows derivations to cyclically reference each other, for example, <programlisting> webServer = derivation { ... hostName = "svn.cs.uu.nl"; services = [svnService]; };   svnService = derivation { ... hostName = webServer.hostName; };</programlisting> Previously, this would yield a black hole (infinite recursion).</para> </listitem> <listitem><para><command>nix-build</command> now defaults to using <filename>./default.nix</filename> if no Nix expression is specified.</para></listitem> <listitem><para><command>nix-instantiate</command>, when applied to a Nix expression that evaluates to a function, will call the function automatically if all its arguments have defaults.</para></listitem> <listitem><para>Nix now uses libtool to build dynamic libraries. This reduces the size of executables.</para></listitem> <listitem><para>A new list concatenation operator <literal>++</literal>. For example, <literal>[1 2 3] ++ [4 5 6]</literal> evaluates to <literal>[1 2 3 4 5 6]</literal>.</para></listitem> <listitem><para>Some currently undocumented primops to support low-level build management using Nix (i.e., using Nix as a Make replacement). See the commit messages for <literal>r3578</literal> and <literal>r3580</literal>.</para></listitem> <listitem><para>Various bug fixes and performance improvements.</para></listitem> </itemizedlist> </section> <!--==================================================================--> <section><title>Release 0.8.1 (April 13, 2005)</title> <para>This is a bug fix release.</para> <itemizedlist> <listitem><para>Patch downloading was broken.</para></listitem> <listitem><para>The garbage collector would not delete paths that had references from invalid (but substitutable) paths.</para></listitem> </itemizedlist> </section> <!--==================================================================--> <section><title>Release 0.8 (April 11, 2005)</title> <para>NOTE: the hashing scheme in Nix 0.8 changed (as detailed below). As a result, <command>nix-pull</command> manifests and channels built for Nix 0.7 and below will now work anymore. However, the Nix expression language has not changed, so you can still build from source. Also, existing user environments continue to work. Nix 0.8 will automatically upgrade the database schema of previous installations when it is first run.</para> <para>If you get the error message <screen> you have an old-style manifest `/nix/var/nix/manifests/[...]'; please delete it</screen> you should delete previously downloaded manifests: <screen> $ rm /nix/var/nix/manifests/*</screen> If <command>nix-channel</command> gives the error message <screen> manifest `http://catamaran.labs.cs.uu.nl/dist/nix/channels/[channel]/MANIFEST' is too old (i.e., for Nix <= 0.7)</screen> then you should unsubscribe from the offending channel (<command>nix-channel --remove <replaceable>URL</replaceable></command>; leave out <literal>/MANIFEST</literal>), and subscribe to the same URL, with <literal>channels</literal> replaced by <literal>channels-v3</literal> (e.g., <link xlink:href='http://catamaran.labs.cs.uu.nl/dist/nix/channels-v3/nixpkgs-unstable' />).</para> <para>Nix 0.8 has the following improvements: <itemizedlist> <listitem><para>The cryptographic hashes used in store paths are now 160 bits long, but encoded in base-32 so that they are still only 32 characters long (e.g., <filename>/nix/store/csw87wag8bqlqk7ipllbwypb14xainap-atk-1.9.0</filename>). (This is actually a 160 bit truncation of a SHA-256 hash.)</para></listitem> <listitem><para>Big cleanups and simplifications of the basic store semantics. The notion of “closure store expressions” is gone (and so is the notion of “successors”); the file system references of a store path are now just stored in the database.</para> <para>For instance, given any store path, you can query its closure: <screen> $ nix-store -qR $(which firefox) ... lots of paths ...</screen> Also, Nix now remembers for each store path the derivation that built it (the “deriver”): <screen> $ nix-store -qR $(which firefox) /nix/store/4b0jx7vq80l9aqcnkszxhymsf1ffa5jd-firefox-1.0.1.drv</screen> So to see the build-time dependencies, you can do <screen> $ nix-store -qR $(nix-store -qd $(which firefox))</screen> or, in a nicer format: <screen> $ nix-store -q --tree $(nix-store -qd $(which firefox))</screen> </para> <para>File system references are also stored in reverse. For instance, you can query all paths that directly or indirectly use a certain Glibc: <screen> $ nix-store -q --referrers-closure \ /nix/store/8lz9yc6zgmc0vlqmn2ipcpkjlmbi51vv-glibc-2.3.4</screen> </para> </listitem> <listitem><para>The concept of fixed-output derivations has been formalised. Previously, functions such as <function>fetchurl</function> in Nixpkgs used a hack (namely, explicitly specifying a store path hash) to prevent changes to, say, the URL of the file from propagating upwards through the dependency graph, causing rebuilds of everything. This can now be done cleanly by specifying the <varname>outputHash</varname> and <varname>outputHashAlgo</varname> attributes. Nix itself checks that the content of the output has the specified hash. (This is important for maintaining certain invariants necessary for future work on secure shared stores.)</para></listitem> <listitem><para>One-click installation :-) It is now possible to install any top-level component in Nixpkgs directly, through the web — see, e.g., <link xlink:href='http://catamaran.labs.cs.uu.nl/dist/nixpkgs-0.8/' />. All you have to do is associate <filename>/nix/bin/nix-install-package</filename> with the MIME type <literal>application/nix-package</literal> (or the extension <filename>.nixpkg</filename>), and clicking on a package link will cause it to be installed, with all appropriate dependencies. If you just want to install some specific application, this is easier than subscribing to a channel.</para></listitem> <listitem><para><command>nix-store -r <replaceable>PATHS</replaceable></command> now builds all the derivations PATHS in parallel. Previously it did them sequentially (though exploiting possible parallelism between subderivations). This is nice for build farms.</para></listitem> <listitem><para><command>nix-channel</command> has new operations <option>--list</option> and <option>--remove</option>.</para></listitem> <listitem><para>New ways of installing components into user environments: <itemizedlist> <listitem><para>Copy from another user environment: <screen> $ nix-env -i --from-profile .../other-profile firefox</screen> </para></listitem> <listitem><para>Install a store derivation directly (bypassing the Nix expression language entirely): <screen> $ nix-env -i /nix/store/z58v41v21xd3...-aterm-2.3.1.drv</screen> (This is used to implement <command>nix-install-package</command>, which is therefore immune to evolution in the Nix expression language.)</para></listitem> <listitem><para>Install an already built store path directly: <screen> $ nix-env -i /nix/store/hsyj5pbn0d9i...-aterm-2.3.1</screen> </para></listitem> <listitem><para>Install the result of a Nix expression specified as a command-line argument: <screen> $ nix-env -f .../i686-linux.nix -i -E 'x: x.firefoxWrapper'</screen> The difference with the normal installation mode is that <option>-E</option> does not use the <varname>name</varname> attributes of derivations. Therefore, this can be used to disambiguate multiple derivations with the same name.</para></listitem> </itemizedlist></para></listitem> <listitem><para>A hash of the contents of a store path is now stored in the database after a succesful build. This allows you to check whether store paths have been tampered with: <command>nix-store --verify --check-contents</command>.</para></listitem> <listitem> <para>Implemented a concurrent garbage collector. It is now always safe to run the garbage collector, even if other Nix operations are happening simultaneously.</para> <para>However, there can still be GC races if you use <command>nix-instantiate</command> and <command>nix-store --realise</command> directly to build things. To prevent races, use the <option>--add-root</option> flag of those commands.</para> </listitem> <listitem><para>The garbage collector now finally deletes paths in the right order (i.e., topologically sorted under the “references” relation), thus making it safe to interrupt the collector without risking a store that violates the closure invariant.</para></listitem> <listitem><para>Likewise, the substitute mechanism now downloads files in the right order, thus preserving the closure invariant at all times.</para></listitem> <listitem><para>The result of <command>nix-build</command> is now registered as a root of the garbage collector. If the <filename>./result</filename> link is deleted, the GC root disappears automatically.</para></listitem> <listitem> <para>The behaviour of the garbage collector can be changed globally by setting options in <filename>/nix/etc/nix/nix.conf</filename>. <itemizedlist> <listitem><para><literal>gc-keep-derivations</literal> specifies whether deriver links should be followed when searching for live paths.</para></listitem> <listitem><para><literal>gc-keep-outputs</literal> specifies whether outputs of derivations should be followed when searching for live paths.</para></listitem> <listitem><para><literal>env-keep-derivations</literal> specifies whether user environments should store the paths of derivations when they are added (thus keeping the derivations alive).</para></listitem> </itemizedlist> </para></listitem> <listitem><para>New <command>nix-env</command> query flags <option>--drv-path</option> and <option>--out-path</option>.</para></listitem> <listitem><para><command>fetchurl</command> allows SHA-1 and SHA-256 in addition to MD5. Just specify the attribute <varname>sha1</varname> or <varname>sha256</varname> instead of <varname>md5</varname>.</para></listitem> <listitem><para>Manual updates.</para></listitem> </itemizedlist> </para> </section> <!--==================================================================--> <section><title>Release 0.7 (January 12, 2005)</title> <itemizedlist> <listitem><para>Binary patching. When upgrading components using pre-built binaries (through nix-pull / nix-channel), Nix can automatically download and apply binary patches to already installed components instead of full downloads. Patching is “smart”: if there is a <emphasis>sequence</emphasis> of patches to an installed component, Nix will use it. Patches are currently generated automatically between Nixpkgs (pre-)releases.</para></listitem> <listitem><para>Simplifications to the substitute mechanism.</para></listitem> <listitem><para>Nix-pull now stores downloaded manifests in <filename>/nix/var/nix/manifests</filename>.</para></listitem> <listitem><para>Metadata on files in the Nix store is canonicalised after builds: the last-modified timestamp is set to 0 (00:00:00 1/1/1970), the mode is set to 0444 or 0555 (readable and possibly executable by all; setuid/setgid bits are dropped), and the group is set to the default. This ensures that the result of a build and an installation through a substitute is the same; and that timestamp dependencies are revealed.</para></listitem> </itemizedlist> </section> <!--==================================================================--> <section><title>Release 0.6 (November 14, 2004)</title> <itemizedlist> <listitem> <para>Rewrite of the normalisation engine. <itemizedlist> <listitem><para>Multiple builds can now be performed in parallel (option <option>-j</option>).</para></listitem> <listitem><para>Distributed builds. Nix can now call a shell script to forward builds to Nix installations on remote machines, which may or may not be of the same platform type.</para></listitem> <listitem><para>Option <option>--fallback</option> allows recovery from broken substitutes.</para></listitem> <listitem><para>Option <option>--keep-going</option> causes building of other (unaffected) derivations to continue if one failed.</para></listitem> </itemizedlist> </para> </listitem> <listitem><para>Improvements to the garbage collector (i.e., it should actually work now).</para></listitem> <listitem><para>Setuid Nix installations allow a Nix store to be shared among multiple users.</para></listitem> <listitem><para>Substitute registration is much faster now.</para></listitem> <listitem><para>A utility <command>nix-build</command> to build a Nix expression and create a symlink to the result int the current directory; useful for testing Nix derivations.</para></listitem> <listitem><para>Manual updates.</para></listitem> <listitem> <para><command>nix-env</command> changes: <itemizedlist> <listitem><para>Derivations for other platforms are filtered out (which can be overriden using <option>--system-filter</option>).</para></listitem> <listitem><para><option>--install</option> by default now uninstall previous derivations with the same name.</para></listitem> <listitem><para><option>--upgrade</option> allows upgrading to a specific version.</para></listitem> <listitem><para>New operation <option>--delete-generations</option> to remove profile generations (necessary for effective garbage collection).</para></listitem> <listitem><para>Nicer output (sorted, columnised).</para></listitem> </itemizedlist> </para> </listitem> <listitem><para>More sensible verbosity levels all around (builder output is now shown always, unless <option>-Q</option> is given).</para></listitem> <listitem> <para>Nix expression language changes: <itemizedlist> <listitem><para>New language construct: <literal>with <replaceable>E1</replaceable>; <replaceable>E2</replaceable></literal> brings all attributes defined in the attribute set <replaceable>E1</replaceable> in scope in <replaceable>E2</replaceable>.</para></listitem> <listitem><para>Added a <function>map</function> function.</para></listitem> <listitem><para>Various new operators (e.g., string concatenation).</para></listitem> </itemizedlist> </para> </listitem> <listitem><para>Expression evaluation is much faster.</para></listitem> <listitem><para>An Emacs mode for editing Nix expressions (with syntax highlighting and indentation) has been added.</para></listitem> <listitem><para>Many bug fixes.</para></listitem> </itemizedlist> </section> <!--==================================================================--> <section><title>Release 0.5 and earlier</title> <para>Please refer to the Subversion commit log messages.</para> </section> </article>