Version 0.8
NOTE: the hashing scheme in Nix 0.8 changed (as detailed below). As a
result, `nix-pull' 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.
If you get the error message
you have an old-style manifest `/nix/var/nix/manifests/[...]';
please delete it
you should delete previously downloaded manifests:
$ rm /nix/var/nix/manifests/*
If `nix-channel' gives the error message
manifest `http://catamaran.labs.cs.uu.nl/dist/nix/channels/[channel]/MANIFEST'
is too old (i.e., for Nix <= 0.7)
then you should unsubscribe from the offending channel (`nix-channel
--remove URL'; leave out `/MANIFEST'), and subscribe to the same URL,
with `channels' replaced by `channels-v3' (e.g.,
http://catamaran.labs.cs.uu.nl/dist/nix/channels-v3/nixpkgs-unstable).
Nix 0.8 has the following improvements:
* 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., /nix/store/csw87wag8bqlqk7ipllbwypb14xainap-atk-1.9.0).
(This is actually a 160 bit truncation of a SHA-256 hash.)
* 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.
For instance, given any store path, you can query its closure:
$ nix-store -qR $(which firefox)
... lots of paths ...
Also, Nix now remembers for each store path the derivation that
built it (the "deriver"):
$ nix-store -qR $(which firefox)
/nix/store/4b0jx7vq80l9aqcnkszxhymsf1ffa5jd-firefox-1.0.1.drv
So to see the build-time dependencies, you can do
$ nix-store -qR $(nix-store -qd $(which firefox))
or, in a nicer format:
$ nix-store -q --tree $(nix-store -qd $(which firefox))
File system references are also stored in reverse. For instance,
you can query all paths that directly or indirectly use a certain
Glibc:
$ nix-store -q --referers-closure \
/nix/store/8lz9yc6zgmc0vlqmn2ipcpkjlmbi51vv-glibc-2.3.4
* The concept of fixed-output derivations has been formalised.
Previously, functions such as `fetchurl' 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 `outputHash' and `outputHashAlgo'
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.)
* One-click installation :-) It is now possible to install any
top-level component in Nixpkgs directly, through the web - see,
e.g., http://catamaran.labs.cs.uu.nl/dist/nixpkgs-0.8/. All you
have to do is associate `/nix/bin/nix-install-package' with the MIME
type `application/nix-package' (or the extension `.nixpkg'), 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.
* `nix-store -r PATHS' 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.
* `nix-channel' has new operations `--list' and `--remove'.
* New ways of installing components into user environments:
- Copy from another user environment:
$ nix-env -i --from-profile .../other-profile firefox
- Install a store derivation directly (bypassing the Nix expression
language entirely):
$ nix-env -i /nix/store/z58v41v21xd3...-aterm-2.3.1.drv
(This is used to implement `nix-install-package', which is
therefore immune to evolution in the Nix expression language.)
- Install an already built store path directly:
$ nix-env -i /nix/store/hsyj5pbn0d9i...-aterm-2.3.1
- Install the result of a Nix expression specified as a command-line
argument:
$ nix-env -f .../i686-linux.nix -i -E 'x: x.firefoxWrapper'
The difference with the normal installation mode is that `-E' does
not use the `name' attributes of derivations. Therefore, this can
be used to disambiguate multiple derivations with the same name.
* 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: `nix-store --verify --check-contents'.
* Implemented a concurrent garbage collector. It is now always safe
to run the garbage collector, even if other Nix operations are
happening simultaneously.
However, there can still be GC races if you use `nix-instantiate'
and `nix-store -r' directly to build things. To prevent races, use
the `--add-root' flag of those commands.
* 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.
* Likewise, the substitute mechanism now downloads files in the right
order, thus preserving the closure invariant at all times.
* The result of `nix-build' is now registered as a root of the garbage
collector. If the `./result' link is deleted, the GC root
disappears automatically.
* The behaviour of the garbage collector can be changed globally by
setting options in `/nix/etc/nix/nix.conf'.
- `gc-keep-derivations' specifies whether deriver links should be
followed when searching for live paths.
- `gc-keep-outputs' specifies whether outputs of derivations should
be followed when searching for live paths.
- `env-keep-derivations' specifies whether user environments should
store the paths of derivations when they are added (thus keeping
the derivations alive).
* New `nix-env' query flags `--drv-path' and `--out-path'.
* `fetchurl' allows SHA-1 and SHA-256 in addition to MD5. Just
specify the attribute `sha1' or `sha256' instead of `md5'.
Version 0.7 (January 12, 2005)
* 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 *sequence* of patches
to an installed component, Nix will use it. Patches are currently
generated automatically between Nixpkgs (pre-)releases.
* Simplifications to the substitute mechanism.
* Nix-pull now stores downloaded manifests in /nix/var/nix/manifests.
* 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.
Version 0.6 (November 14, 2004)
Major changes include the following:
* Rewrite of the normalisation engine.
* Multiple builds can now be performed in parallel (option `-j').
* 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.
* Option `--fallback' allows recovery from broken substitutes.
* Option `--keep-going' causes building of other (unaffected)
derivations to continue if one failed.
* Improvements to the garbage collector (i.e., it should actually work
now).
* Setuid Nix installations allow a Nix store to be shared among
multiple users.
* Substitute registration is much faster now.
* A utility `nix-build' to build a Nix expression and create a symlink
to the result int the current directory; useful for testing Nix
derivations.
* Manual updates.
* `nix-env' changes:
* Derivations for other platforms are filtered out (which can be
overriden using `--system-filter').
* `--install' by default now uninstall previous derivations with the
same name.
* `--upgrade' allows upgrading to a specific version.
* New operation `--delete-generations' to remove profile
generations (necessary for effective garbage collection).
* Nicer output (sorted, columnised).
* More sensible verbosity levels all around (builder output is now
shown always, unless `-Q' is given).
* Nix expression language changes:
* New language construct: `with E1; E2' brings all attributes
defined in the attribute set E1 in scope in E2.
* Added a `map' function.
* Various new operators (e.g., string concatenation).
* Expression evaluation is much faster.
* An Emacs mode for editing Nix expressions (with syntax highlighting
and indentation) has been added.
* Many bug fixes.
Version 0.5 and earlier
Please refer to the Subversion commit log messages.
