Commit graph

11 commits

Author SHA1 Message Date
John Ericson
018e2571aa Test store paths, with property tests
The property test in fact found a bug: we were excluding numbers!
2023-01-23 07:05:50 -05:00
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
John Ericson
7a2b566dc8 Move StorePathWithOutputs into its own header/file
In the following commits it will become less prevalent.
2021-04-05 08:31:37 -04:00
Eelco Dolstra
c0dd05131e toStorePath(): Return a StorePath and the suffix 2020-07-13 16:25:48 +02:00
Eelco Dolstra
29542865ce Remove StorePath::clone() and related functions 2020-06-16 22:20:18 +02:00
Eelco Dolstra
759947bf72 StorePath: Rewrite in C++
On nix-env -qa -f '<nixpkgs>', this reduces maximum RSS by 20970 KiB
and runtime by 0.8%. This is mostly because we're not parsing the hash
part as a hash anymore (just validating that it consists of base-32
characters).

Also, replace storePathToHash() by StorePath::hashPart().
2020-06-16 14:28:41 +02:00
Eelco Dolstra
d37dc71e3c
nix-build: Fix !<output> handling
This was broken by 22a754c091.

https://hydra.nixos.org/eval/1573669
2020-03-04 13:56:17 +01:00
Eelco Dolstra
22a754c091
Fix GC failures on bad store path names
It failed on names like '/nix/store/9ip48nkc9rfy0a4yaw98lp6gipqlib1a-'.
2020-02-28 18:07:10 +01:00
Eelco Dolstra
aef635da78 Fix derivation computation with __structuredAttrs and multiple outputs
Fixes

  error: derivation '/nix/store/klivma7r7h5lndb99f7xxmlh5whyayvg-zlib-1.2.11.drv' has incorrect output '/nix/store/fv98nnx5ykgbq8sqabilkgkbc4169q05-zlib-1.2.11-dev', should be '/nix/store/adm7pilzlj3z5k249s8b4wv3scprhzi1-zlib-1.2.11-dev'
2020-01-21 21:14:13 +01:00
Eelco Dolstra
54bf5ba422 nix-store -r: Handle symlinks to store paths
Fixes #3270.
2019-12-16 19:11:47 +01:00
Eelco Dolstra
bbe97dff8b Make the Store API more type-safe
Most functions now take a StorePath argument rather than a Path (which
is just an alias for std::string). The StorePath constructor ensures
that the path is syntactically correct (i.e. it looks like
<store-dir>/<base32-hash>-<name>). Similarly, functions like
buildPaths() now take a StorePathWithOutputs, rather than abusing Path
by adding a '!<outputs>' suffix.

Note that the StorePath type is implemented in Rust. This involves
some hackery to allow Rust values to be used directly in C++, via a
helper type whose destructor calls the Rust type's drop()
function. The main issue is the dynamic nature of C++ move semantics:
after we have moved a Rust value, we should not call the drop function
on the original value. So when we move a value, we set the original
value to bitwise zero, and the destructor only calls drop() if the
value is not bitwise zero. This should be sufficient for most types.

Also lots of minor cleanups to the C++ API to make it more modern
(e.g. using std::optional and std::string_view in some places).
2019-12-10 22:06:05 +01:00