Commit graph

10 commits

Author SHA1 Message Date
Eelco Dolstra b95faccf03 Merge remote-tracking branch 'origin/master' into auto-uid-allocation 2022-11-03 17:43:40 +01:00
Tom Bereknyei 7a04fb1c56 repl: add repl-flake experimental feature for gating 2022-05-20 08:20:00 -04:00
Alain Zscheile 1385b20078
Get rid of most .at calls (#6393)
Use one of `get` or `getOr` instead which will either return a null-pointer (with a nicer error message) or a default value when the key is missing.
2022-05-04 07:44:32 +02:00
Eelco Dolstra a3c6c5b1c7 nix profile: Support overriding outputs 2022-05-03 15:00:34 +02:00
Yorick ebf2fd76b1
Add custom to_json and from_json functions for ExperimentalFeature
nix show-config --json was serializing experimental features as ints.
nlohmann::json will automatically use these definitions to serialize
and deserialize ExperimentalFeatures.

Strictly, we don't use the from_json instance yet, it's provided for
completeness and hopefully future use.
2022-04-20 15:41:01 +02:00
Eelco Dolstra 5cd72598fe Add support for impure derivations
Impure derivations are derivations that can produce a different result
every time they're built. Example:

  stdenv.mkDerivation {
    name = "impure";
    __impure = true; # marks this derivation as impure
    outputHashAlgo = "sha256";
    outputHashMode = "recursive";
    buildCommand = "date > $out";
  };

Some important characteristics:

* This requires the 'impure-derivations' experimental feature.

* Impure derivations are not "cached". Thus, running "nix-build" on
  the example above multiple times will cause a rebuild every time.

* They are implemented similar to CA derivations, i.e. the output is
  moved to a content-addressed path in the store. The difference is
  that we don't register a realisation in the Nix database.

* Pure derivations are not allowed to depend on impure derivations. In
  the future fixed-output derivations will be allowed to depend on
  impure derivations, thus forming an "impurity barrier" in the
  dependency graph.

* When sandboxing is enabled, impure derivations can access the
  network in the same way as fixed-output derivations. In relaxed
  sandboxing mode, they can access the local filesystem.
2022-03-31 13:43:20 +02:00
Eelco Dolstra f902f3c2cb Add experimental feature 'fetch-closure' 2022-03-24 21:33:33 +01:00
John Ericson dc92b01885 Merge remote-tracking branch 'upstream/master' into auto-uid-allocation 2022-02-28 23:54:20 +00:00
Eelco Dolstra 0d9e050ba7 parseExperimentalFeature(): Initialize atomically 2021-10-26 14:29:48 +02:00
regnat af99941279 Make experimental-features a proper type
Rather than having them plain strings scattered through the whole
codebase, create an enum containing all the known experimental features.

This means that
- Nix can now `warn` when an unkwown experimental feature is passed
  (making it much nicer to spot typos and spot deprecated features)
- It’s now easy to remove a feature altogether (once the feature isn’t
  experimental anymore or is dropped) by just removing the field for the
  enum and letting the compiler point us to all the now invalid usages
  of it.
2021-10-26 07:02:31 +02:00