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10 commits

Author SHA1 Message Date
Eelco Dolstra ca8caaec5e nix: Add --expr flag
This replaces the '(...)' installable syntax, which is not very
discoverable. The downside is that you can't have multiple expressions
or mix expressions and other installables.
2019-11-27 00:05:30 +01:00
Eelco Dolstra ee1254d4f5 nix: Add --impure as a shorter alias of --no-pure-eval 2019-04-08 23:19:19 +02:00
Eelco Dolstra d2875f6782 Fix tests 2019-04-08 16:11:36 +02:00
Eelco Dolstra d4dcffd643
Add pure evaluation mode
In this mode, the following restrictions apply:

* The builtins currentTime, currentSystem and storePath throw an
  error.

* $NIX_PATH and -I are ignored.

* fetchGit and fetchMercurial require a revision hash.

* fetchurl and fetchTarball require a sha256 attribute.

* No file system access is allowed outside of the paths returned by
  fetch{Git,Mercurial,url,Tarball}. Thus 'nix build -f ./foo.nix' is
  not allowed.

Thus, the evaluation result is completely reproducible from the
command line arguments. E.g.

  nix build --pure-eval '(
    let
      nix = fetchGit { url = https://github.com/NixOS/nixpkgs.git; rev = "9c927de4b179a6dd210dd88d34bda8af4b575680"; };
      nixpkgs = fetchGit { url = https://github.com/NixOS/nixpkgs.git; ref = "release-17.09"; rev = "66b4de79e3841530e6d9c6baf98702aa1f7124e4"; };
    in (import (nix + "/release.nix") { inherit nix nixpkgs; }).build.x86_64-linux
  )'

The goal is to enable completely reproducible and traceable
evaluation. For example, a NixOS configuration could be fully
described by a single Git commit hash. 'nixos-rebuild' would do
something like

  nix build --pure-eval '(
    (import (fetchGit { url = file:///my-nixos-config; rev = "..."; })).system
  ')

where the Git repository /my-nixos-config would use further fetchGit
calls or Git externals to fetch Nixpkgs and whatever other
dependencies it has. Either way, the commit hash would uniquely
identify the NixOS configuration and allow it to reproduced.
2018-01-16 19:23:18 +01:00
Eelco Dolstra d7da6c9ea9
fetchGit/fetchMercurial: Fix directory inclusion check
E.g. the existence of .gitignore would cause .git to be included.
2017-11-21 19:34:46 +01:00
Eelco Dolstra fd10f6f241
Show when tests are skipped
Also, don't depend on tput (ncurses). It's really not needed since
ANSI escape sequences have been standardized for 35 years or so.
2017-11-07 12:09:57 +01:00
Eelco Dolstra ee6ac38848
fetchGit/fetchMercurial: Filter out directories with untracked files 2017-11-03 13:55:31 +01:00
Eelco Dolstra 4dee01da7c
fetchGit: Add a test 2017-11-03 13:55:30 +01:00
Eelco Dolstra e026bc3b05
fetchMercurial: Don't fetch hashes we already have 2017-11-01 18:43:11 +01:00
Eelco Dolstra 1969f357b7
Add fetchMercurial primop
E.g.

  $ nix eval '(fetchMercurial https://www.mercurial-scm.org/repo/hello)'
  { branch = "default"; outPath = "/nix/store/alvb9y1kfz42bjishqmyy3pphnrh1pfa-source"; rev = "82e55d328c8ca4ee16520036c0aaace03a5beb65"; revCount = 1; shortRev = "82e55d328c8c"; }

  $ nix eval '(fetchMercurial { url = https://www.mercurial-scm.org/repo/hello; rev = "0a04b987be5ae354b710cefeba0e2d9de7ad41a9"; })'
  { branch = "default"; outPath = "/nix/store/alvb9y1kfz42bjishqmyy3pphnrh1pfa-source"; rev = "0a04b987be5ae354b710cefeba0e2d9de7ad41a9"; revCount = 0; shortRev = "0a04b987be5a"; }

  $ nix eval '(fetchMercurial /tmp/unclean-hg-tree)'
  { branch = "default"; outPath = "/nix/store/cm750cdw1x8wfpm3jq7mz09r30l9r024-source"; rev = "0000000000000000000000000000000000000000"; revCount = 0; shortRev = "000000000000"; }
2017-11-01 17:45:32 +01:00