Release 0.10 (2006-10-06)
Note
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
$ nix-store --clear-substitutesfirst.
Warning
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.
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nix-envusability improvements:-
An option
--compare-versions(or-c) has been added tonix-env --queryto 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 isnix-env -qc \*. -
nix-env --querynow takes as arguments a list of package names about which to show information, just like--install, etc.: for example,nix-env -q gcc. Note that to show all derivations, you need to specify\*. -
nix-env -i pkgnamewill now install the highest available version of pkgname, rather than installing all available versions (which would probably give collisions) (NIX-31). -
nix-env (-i|-u) --dry-runnow shows exactly which missing paths will be built or substituted. -
nix-env -qa --descriptionshows human-readable descriptions of packages, provided that they have ameta.descriptionattribute (which most packages in Nixpkgs don’t have yet).
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New language features:
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Reference scanning (which happens after each build) is much faster and takes a constant amount of memory.
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String interpolation. Expressions like
"--with-freetype2-library=" + freetype + "/lib"can now be written as
"--with-freetype2-library=${freetype}/lib"You can write arbitrary expressions within
${...}, not just identifiers. -
Multi-line string literals.
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String concatenations can now involve derivations, as in the example
"--with-freetype2-library=" + freetype + "/lib". This was not previously possible because we need to register that a derivation that uses such a string is dependent onfreetype. The evaluator now properly propagates this information. Consequently, the subpath operator (~) has been deprecated. -
Default values of function arguments can now refer to other function arguments; that is, all arguments are in scope in the default values (
NIX-45). -
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
builtins, allowing one to test for the availability of primop in a backwards-compatible way. -
Real let-expressions:
let x = ...; ... z = ...; in ....
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New commands
nix-pack-closureandnix-unpack-closurethan 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. -
XML support:
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nix-env -q --xmlprints the installed or available packages in an XML representation for easy processing by other tools. -
nix-instantiate --eval-only --xmlprints an XML representation of the resulting term. (The new flag--strictforces ‘deep’ evaluation of the result, i.e., list elements and attributes are evaluated recursively.) -
In Nix expressions, the primop
builtins.toXMLconverts a term to an XML representation. This is primarily useful for passing structured information to builders.
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You can now unambiguously specify which derivation to build or install in
nix-env,nix-instantiateandnix-buildusing the--attr/-Aflags, which takes an attribute name as argument. (Unlike symbolic package names such assubversion-1.4.0, attribute names in an attribute set are unique.) For instance, a quick way to perform a test build of a package in Nixpkgs isnix-build pkgs/top-level/all-packages.nix -A foo.nix-env -q --attrshows the attribute names corresponding to each derivation. -
If the top-level Nix expression used by
nix-env,nix-instantiateornix-buildevaluates to a function whose arguments all have default values, the function will be called automatically. Also, the new command-line switch--arg name valuecan be used to specify function arguments on the command line. -
nix-install-package --url URLallows a package to be installed directly from the given URL. -
Nix now works behind an HTTP proxy server; just set the standard environment variables
http_proxy,https_proxy,ftp_proxyorall_proxyappropriately. Functions such asfetchurlin Nixpkgs also respect these variables. -
nix-build -o symlinkallows the symlink to the build result to be named something other thanresult. -
Platform support:
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Support for 64-bit platforms, provided a suitably patched ATerm library is used. Also, files larger than 2 GiB are now supported.
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Added support for Cygwin (Windows,
i686-cygwin), Mac OS X on Intel (i686-darwin) and Linux on PowerPC (powerpc-linux). -
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
build-max-jobssetting.
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Garbage collector improvements:
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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 (
find-runtime-roots.pl) is inherently system-specific, but it should work on Linux and on all platforms that have thelsofutility. -
nix-store --gc(a.k.a.nix-collect-garbage) prints out the number of bytes freed on standard output.nix-store --gc --print-deadshows how many bytes would be freed by an actual garbage collection. -
nix-collect-garbage -dremoves all old generations of all profiles before calling the actual garbage collector (nix-store --gc). This is an easy way to get rid of all old packages in the Nix store. -
nix-storenow has an operation--deleteto delete specific paths from the Nix store. It won’t delete reachable (non-garbage) paths unless--ignore-livenessis specified.
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Berkeley DB 4.4’s process registry feature is used to recover from crashed Nix processes.
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A performance issue has been fixed with the
referertable, which stores the inverse of thereferencestable (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) (NIX-23). -
Nix now catches the
TERMandHUPsignals in addition to theINTsignal. So you can now do akillall nix-storewithout triggering a database recovery. -
bsdiffupdated to version 4.3. -
Substantial performance improvements in expression evaluation and
nix-env -qa, all thanks to Valgrind. Memory use has been reduced by a factor 8 or so. Big speedup by memoisation of path hashing. -
Lots of bug fixes, notably:
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Make sure that the garbage collector can run successfully when the disk is full (
NIX-18). -
nix-envnow locks the profile to prevent races between concurrentnix-envoperations on the same profile (NIX-7). -
Removed misleading messages from
nix-env -i(e.g.,installing `foo'followed byuninstalling `foo') (NIX-17).
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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).
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Header files are now installed so that external programs can use the Nix libraries.