1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
#include "experimental-features.hh"
#include "util.hh"
#include "nlohmann/json.hpp"
namespace nix {
std::map<ExperimentalFeature, std::pair<std::string, std::string>> stringifiedXpFeatures = {
{ Xp::CaDerivations, {"ca-derivations", R"(
Allows derivations to be content-addressed in order to prevent rebuilds
when changes to the derivation do not result in changes to the
derivation's output. See
[__contentAddressed](../language/advanced-attributes.md#adv-attr-__contentAddressed)
for more info.
)"} },
{ Xp::ImpureDerivations, {"impure-derivations", R"(
Allows derivations to produce non-fixed outputs by setting the `__impure`
derivation attribute to `true`. See [these release
notes](../release-notes/rl-2.8.md) for an example.
)"} },
{ Xp::Flakes, {"flakes", R"(
Allows for derivations to be packaged in flakes. See the manual entry for
[`nix flake`](../command-ref/new-cli/nix3-flake.md) or this [detailed
introduction](https://www.tweag.io/blog/2020-05-25-flakes/) for more info.
)"} },
{ Xp::NixCommand, {"nix-command", R"(
Allows the usage of the new `nix` CLI subcommands, such as `nix build`, `nix
develop`, `nix run`, etc. See the manual for
[`nix`](../command-ref/new-cli/nix.md) for more info.
)"} },
{ Xp::RecursiveNix, {"recursive-nix", R"(
Allow Nix derivations to call Nix in order to recursively build derivations.
See [this
commit](https://github.com/edolstra/nix/commit/1a27aa7d64ffe6fc36cfca4d82bdf51c4d8cf717)
for more info.
)"} },
{ Xp::NoUrlLiterals, {"no-url-literals", R"(
Disallows unquoted URLs as part of the Nix language syntax. See [RFC
45](https://github.com/NixOS/rfcs/pull/45) for more info.
)"} },
{ Xp::FetchClosure, {"fetch-closure", R"(
Enables the use of the `fetchClosure` function in the standard library. See
the docs for [`fetchClosure`](../language/builtins.md#builtins-fetchClosure)
for more info.
)"} },
{ Xp::ReplFlake, {"repl-flake", R"(
Allows the user to enter a Nix REPL within a flake, e.g. `nix repl nixpkgs`
or `nix repl .#foo`.
)"} },
{ Xp::AutoAllocateUids, {"auto-allocate-uids", R"(
Allows Nix to automatically pick UIDs for builds, rather than creating
`nixbld*` user accounts. See [here](#conf-auto-allocate-uids) for more info.
)"} },
{ Xp::Cgroups, {"cgroups", R"(
Allows Nix to execute builds inside cgroups. See
[`use-cgroups`](#conf-use-cgroups) for more info.
)"} },
{ Xp::DiscardReferences, {"discard-references", R"(
Enables the use of the `unsafeDiscardReferences` attribute in derivations
that use structured attributes. This disables scanning of outputs for
runtime dependencies.
)"} },
};
const std::optional<ExperimentalFeature> parseExperimentalFeature(const std::string_view & name)
{
using ReverseXpMap = std::map<std::string_view, ExperimentalFeature>;
static auto reverseXpMap = []()
{
auto reverseXpMap = std::make_unique<ReverseXpMap>();
std::string_view name;
for (auto & [feature, featureStringPair] : stringifiedXpFeatures) {
name = featureStringPair.first;
(*reverseXpMap)[name] = feature;
}
return reverseXpMap;
}();
if (auto feature = get(*reverseXpMap, name))
return *feature;
else
return std::nullopt;
}
std::string_view showExperimentalFeature(const ExperimentalFeature feature)
{
const auto ret = get(stringifiedXpFeatures, feature);
assert(ret);
return ret->first;
}
std::string getExperimentalFeaturesList() {
std::string experimentalFeaturesList = R"(
Experimental Nix features to enable.
Current experimental features are the following:
)";
std::string experimentalFeatureString;
for (auto& [feature, featureStringPair] : stringifiedXpFeatures) {
experimentalFeatureString = " - `" + featureStringPair.first + "`\n";
experimentalFeatureString += featureStringPair.second + "\n\n";
experimentalFeaturesList += experimentalFeatureString;
}
return experimentalFeaturesList;
}
std::set<ExperimentalFeature> parseFeatures(const std::set<std::string> & rawFeatures)
{
std::set<ExperimentalFeature> res;
for (auto & rawFeature : rawFeatures) {
if (auto feature = parseExperimentalFeature(rawFeature))
res.insert(*feature);
}
return res;
}
MissingExperimentalFeature::MissingExperimentalFeature(ExperimentalFeature feature)
: Error("experimental Nix feature '%1%' is disabled; use '--extra-experimental-features %1%' to override", showExperimentalFeature(feature))
, missingFeature(feature)
{}
std::ostream & operator <<(std::ostream & str, const ExperimentalFeature & feature)
{
return str << showExperimentalFeature(feature);
}
void to_json(nlohmann::json & j, const ExperimentalFeature & feature)
{
j = showExperimentalFeature(feature);
}
void from_json(const nlohmann::json & j, ExperimentalFeature & feature)
{
const std::string input = j;
const auto parsed = parseExperimentalFeature(input);
if (parsed.has_value())
feature = *parsed;
else
throw Error("Unknown experimental feature '%s' in JSON input", input);
}
}
|
