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diff --git a/doc/manual/src/release-notes/rl-1.2.md b/doc/manual/src/release-notes/rl-1.2.md new file mode 100644 index 000000000..25b830955 --- /dev/null +++ b/doc/manual/src/release-notes/rl-1.2.md @@ -0,0 +1,97 @@ +# Release 1.2 (2012-12-06) + +This release has the following improvements and changes: + + - Nix has a new binary substituter mechanism: the *binary cache*. A + binary cache contains pre-built binaries of Nix packages. Whenever + Nix wants to build a missing Nix store path, it will check a set of + binary caches to see if any of them has a pre-built binary of that + path. The configuration setting `binary-caches` contains a list of + URLs of binary caches. For instance, doing + + $ nix-env -i thunderbird --option binary-caches http://cache.nixos.org + + will install Thunderbird and its dependencies, using the available + pre-built binaries in <http://cache.nixos.org>. The main advantage + over the old “manifest”-based method of getting pre-built binaries + is that you don’t have to worry about your manifest being in sync + with the Nix expressions you’re installing from; i.e., you don’t + need to run `nix-pull` to update your manifest. It’s also more + scalable because you don’t need to redownload a giant manifest file + every time. + + A Nix channel can provide a binary cache URL that will be used + automatically if you subscribe to that channel. If you use the + Nixpkgs or NixOS channels (<http://nixos.org/channels>) you + automatically get the cache <http://cache.nixos.org>. + + Binary caches are created using `nix-push`. For details on the + operation and format of binary caches, see the `nix-push` manpage. + More details are provided in [this nix-dev + posting](https://nixos.org/nix-dev/2012-September/009826.html). + + - Multiple output support should now be usable. A derivation can + declare that it wants to produce multiple store paths by saying + something like + + outputs = [ "lib" "headers" "doc" ]; + + This will cause Nix to pass the intended store path of each output + to the builder through the environment variables `lib`, `headers` + and `doc`. Other packages can refer to a specific output by + referring to `pkg.output`, e.g. + + buildInputs = [ pkg.lib pkg.headers ]; + + If you install a package with multiple outputs using `nix-env`, each + output path will be symlinked into the user environment. + + - Dashes are now valid as part of identifiers and attribute names. + + - The new operation `nix-store --repair-path` allows corrupted or + missing store paths to be repaired by redownloading them. `nix-store + --verify --check-contents + --repair` will scan and repair all paths in the Nix store. + Similarly, `nix-env`, `nix-build`, `nix-instantiate` and `nix-store + --realise` have a `--repair` flag to detect and fix bad paths by + rebuilding or redownloading them. + + - Nix no longer sets the immutable bit on files in the Nix store. + Instead, the recommended way to guard the Nix store against + accidental modification on Linux is to make it a read-only bind + mount, like this: + + $ mount --bind /nix/store /nix/store + $ mount -o remount,ro,bind /nix/store + + Nix will automatically make `/nix/store` writable as needed (using a + private mount namespace) to allow modifications. + + - Store optimisation (replacing identical files in the store with hard + links) can now be done automatically every time a path is added to + the store. This is enabled by setting the configuration option + `auto-optimise-store` to `true` (disabled by default). + + - Nix now supports `xz` compression for NARs in addition to `bzip2`. + It compresses about 30% better on typical archives and decompresses + about twice as fast. + + - Basic Nix expression evaluation profiling: setting the environment + variable `NIX_COUNT_CALLS` to `1` will cause Nix to print how many + times each primop or function was executed. + + - New primops: `concatLists`, `elem`, `elemAt` and `filter`. + + - The command `nix-copy-closure` has a new flag `--use-substitutes` + (`-s`) to download missing paths on the target machine using the + substitute mechanism. + + - The command `nix-worker` has been renamed to `nix-daemon`. Support + for running the Nix worker in “slave” mode has been removed. + + - The `--help` flag of every Nix command now invokes `man`. + + - Chroot builds are now supported on systemd machines. + +This release has contributions from Eelco Dolstra, Florian Friesdorf, +Mats Erik Andersson and Shea Levy. |