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author | Eelco Dolstra <edolstra@gmail.com> | 2022-03-31 17:33:06 +0200 |
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committer | Eelco Dolstra <edolstra@gmail.com> | 2022-03-31 17:33:06 +0200 |
commit | d63a5f5dd3b47e629295eb68264b4a6aadc65aa7 (patch) | |
tree | 5c24a5a282da46d9cd1b9daee97f72e10850559b /doc/manual/src/release-notes/rl-next.md | |
parent | 75370972847a1b992055085f39b38f1f659e5275 (diff) |
Update release notes
Diffstat (limited to 'doc/manual/src/release-notes/rl-next.md')
-rw-r--r-- | doc/manual/src/release-notes/rl-next.md | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/doc/manual/src/release-notes/rl-next.md b/doc/manual/src/release-notes/rl-next.md index 2ec864ee4..4f3c9ce41 100644 --- a/doc/manual/src/release-notes/rl-next.md +++ b/doc/manual/src/release-notes/rl-next.md @@ -14,3 +14,21 @@ This function is only available if you enable the experimental feature `fetch-closure`. + +* New experimental feature: *impure derivations*. These are + derivations that can produce a different result every time they're + built. Here is an example: + + ```nix + stdenv.mkDerivation { + name = "impure"; + __impure = true; # marks this derivation as impure + buildCommand = "date > $out"; + } + ``` + + Running `nix build` twice on this expression will build the + derivation twice, producing two different content-addressed store + paths. Like fixed-output derivations, impure derivations have access + to the network. Only fixed-output derivations and impure derivations + can depend on an impure derivation. |