diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/libexpr/flake/lockfile.cc | 5 | ||||
| -rw-r--r-- | src/libexpr/flake/lockfile.hh | 3 | ||||
| -rw-r--r-- | src/libutil/config.cc | 16 | ||||
| -rw-r--r-- | src/libutil/config.hh | 19 | ||||
| -rw-r--r-- | src/libutil/experimental-features.cc | 241 | ||||
| -rw-r--r-- | src/libutil/experimental-features.hh | 42 | ||||
| -rw-r--r-- | src/libutil/util.hh | 10 | ||||
| -rw-r--r-- | src/nix/main.cc | 5 |
8 files changed, 288 insertions, 53 deletions
diff --git a/src/libexpr/flake/lockfile.cc b/src/libexpr/flake/lockfile.cc index a74e68c9c..ba2fd46f0 100644 --- a/src/libexpr/flake/lockfile.cc +++ b/src/libexpr/flake/lockfile.cc @@ -234,6 +234,11 @@ bool LockFile::operator ==(const LockFile & other) const return toJSON() == other.toJSON(); } +bool LockFile::operator !=(const LockFile & other) const +{ + return !(*this == other); +} + InputPath parseInputPath(std::string_view s) { InputPath path; diff --git a/src/libexpr/flake/lockfile.hh b/src/libexpr/flake/lockfile.hh index 0ac731b5d..ba4c0c848 100644 --- a/src/libexpr/flake/lockfile.hh +++ b/src/libexpr/flake/lockfile.hh @@ -73,6 +73,9 @@ struct LockFile std::optional<FlakeRef> isUnlocked() const; bool operator ==(const LockFile & other) const; + // Needed for old gcc versions that don't synthesize it (like gcc 8.2.2 + // that is still the default on aarch64-linux) + bool operator !=(const LockFile & other) const; std::shared_ptr<Node> findInput(const InputPath & path); diff --git a/src/libutil/config.cc b/src/libutil/config.cc index 8d63536d6..5ff8d91ba 100644 --- a/src/libutil/config.cc +++ b/src/libutil/config.cc @@ -70,17 +70,10 @@ void AbstractConfig::reapplyUnknownSettings() set(s.first, s.second); } -// Whether we should process the option. Excludes aliases, which are handled elsewhere, and disabled features. -static bool applicable(const Config::SettingData & sd) -{ - return !sd.isAlias - && experimentalFeatureSettings.isEnabled(sd.setting->experimentalFeature); -} - void Config::getSettings(std::map<std::string, SettingInfo> & res, bool overriddenOnly) { for (auto & opt : _settings) - if (applicable(opt.second) && (!overriddenOnly || opt.second.setting->overridden)) + if (!opt.second.isAlias && (!overriddenOnly || opt.second.setting->overridden)) res.emplace(opt.first, SettingInfo{opt.second.setting->to_string(), opt.second.setting->description}); } @@ -154,7 +147,7 @@ nlohmann::json Config::toJSON() { auto res = nlohmann::json::object(); for (auto & s : _settings) - if (applicable(s.second)) + if (!s.second.isAlias) res.emplace(s.first, s.second.setting->toJSON()); return res; } @@ -163,7 +156,7 @@ std::string Config::toKeyValue() { auto res = std::string(); for (auto & s : _settings) - if (applicable(s.second)) + if (s.second.isAlias) res += fmt("%s = %s\n", s.first, s.second.setting->to_string()); return res; } @@ -171,9 +164,6 @@ std::string Config::toKeyValue() void Config::convertToArgs(Args & args, const std::string & category) { for (auto & s : _settings) { - /* We do include args for settings gated on disabled - experimental-features. The args themselves however will also be - gated on any experimental feature the underlying setting is. */ if (!s.second.isAlias) s.second.setting->convertToArg(args, category); } diff --git a/src/libutil/config.hh b/src/libutil/config.hh index 3c1d70294..162626791 100644 --- a/src/libutil/config.hh +++ b/src/libutil/config.hh @@ -371,8 +371,23 @@ extern GlobalConfig globalConfig; struct ExperimentalFeatureSettings : Config { - Setting<std::set<ExperimentalFeature>> experimentalFeatures{this, {}, "experimental-features", - "Experimental Nix features to enable."}; + Setting<std::set<ExperimentalFeature>> experimentalFeatures{ + this, {}, "experimental-features", + R"( + Experimental features that are enabled. + + Example: + + ``` + experimental-features = nix-command flakes + ``` + + The following experimental features are available: + + {{#include experimental-features-shortlist.md}} + + Experimental features are [further documented in the manual](@docroot@/contributing/experimental-features.md). + )"}; /** * Check whether the given experimental feature is enabled. diff --git a/src/libutil/experimental-features.cc b/src/libutil/experimental-features.cc index 32aa66db1..be5a2c088 100644 --- a/src/libutil/experimental-features.cc +++ b/src/libutil/experimental-features.cc @@ -5,30 +5,218 @@ namespace nix { -std::map<ExperimentalFeature, std::string> stringifiedXpFeatures = { - { Xp::CaDerivations, "ca-derivations" }, - { Xp::ImpureDerivations, "impure-derivations" }, - { Xp::Flakes, "flakes" }, - { Xp::NixCommand, "nix-command" }, - { Xp::RecursiveNix, "recursive-nix" }, - { Xp::NoUrlLiterals, "no-url-literals" }, - { Xp::FetchClosure, "fetch-closure" }, - { Xp::ReplFlake, "repl-flake" }, - { Xp::AutoAllocateUids, "auto-allocate-uids" }, - { Xp::Cgroups, "cgroups" }, - { Xp::DiscardReferences, "discard-references" }, - { Xp::NixTesting, "nix-testing" }, +struct ExperimentalFeatureDetails +{ + ExperimentalFeature tag; + std::string_view name; + std::string_view description; }; +constexpr std::array<ExperimentalFeatureDetails, 12> xpFeatureDetails = {{ + { + .tag = Xp::CaDerivations, + .name = "ca-derivations", + .description = R"( + Allow 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](@docroot@/language/advanced-attributes.md#adv-attr-__contentAddressed) + for details. + )", + }, + { + .tag = Xp::ImpureDerivations, + .name = "impure-derivations", + .description = R"( + Allow derivations to produce non-fixed outputs by setting the + `__impure` derivation attribute to `true`. An impure derivation can + have differing outputs each time it is built. + + Example: + + ``` + derivation { + name = "impure"; + builder = /bin/sh; + __impure = true; # mark this derivation as impure + args = [ "-c" "read -n 10 random < /dev/random; echo $random > $out" ]; + system = builtins.currentSystem; + } + ``` + + Each time this derivation is built, it can produce a different + output (as the builder outputs random bytes to `$out`). Impure + derivations also have access to the network, and only fixed-output + or other impure derivations can rely on impure derivations. Finally, + an impure derivation cannot also be + [content-addressed](#xp-feature-ca-derivations). + )", + }, + { + .tag = Xp::Flakes, + .name = "flakes", + .description = R"( + Enable flakes. See the manual entry for [`nix + flake`](@docroot@/command-ref/new-cli/nix3-flake.md) for details. + )", + }, + { + .tag = Xp::NixCommand, + .name = "nix-command", + .description = R"( + Enable the new `nix` subcommands. See the manual on + [`nix`](@docroot@/command-ref/new-cli/nix.md) for details. + )", + }, + { + .tag = Xp::RecursiveNix, + .name = "recursive-nix", + .description = R"( + Allow derivation builders to call Nix, and thus build derivations + recursively. + + Example: + + ``` + with import <nixpkgs> {}; + + runCommand "foo" + { + buildInputs = [ nix jq ]; + NIX_PATH = "nixpkgs=${<nixpkgs>}"; + } + '' + hello=$(nix-build -E '(import <nixpkgs> {}).hello.overrideDerivation (args: { name = "recursive-hello"; })') + + mkdir -p $out/bin + ln -s $hello/bin/hello $out/bin/hello + '' + ``` + + An important restriction on recursive builders is disallowing + arbitrary substitutions. For example, running + + ``` + nix-store -r /nix/store/kmwd1hq55akdb9sc7l3finr175dajlby-hello-2.10 + ``` + + in the above `runCommand` script would be disallowed, as this could + lead to derivations with hidden dependencies or breaking + reproducibility by relying on the current state of the Nix store. An + exception would be if + `/nix/store/kmwd1hq55akdb9sc7l3finr175dajlby-hello-2.10` were + already in the build inputs or built by a previous recursive Nix + call. + )", + }, + { + .tag = Xp::NoUrlLiterals, + .name = "no-url-literals", + .description = R"( + Disallow unquoted URLs as part of the Nix language syntax. The Nix + language allows for URL literals, like so: + + ``` + $ nix repl + Welcome to Nix 2.15.0. Type :? for help. + + nix-repl> http://foo + "http://foo" + ``` + + But enabling this experimental feature will cause the Nix parser to + throw an error when encountering a URL literal: + + ``` + $ nix repl --extra-experimental-features 'no-url-literals' + Welcome to Nix 2.15.0. Type :? for help. + + nix-repl> http://foo + error: URL literals are disabled + + at «string»:1:1: + + 1| http://foo + | ^ + + ``` + + While this is currently an experimental feature, unquoted URLs are + being deprecated and their usage is discouraged. + + The reason is that, as opposed to path literals, URLs have no + special properties that distinguish them from regular strings, URLs + containing parameters have to be quoted anyway, and unquoted URLs + may confuse external tooling. + )", + }, + { + .tag = Xp::FetchClosure, + .name = "fetch-closure", + .description = R"( + Enable the use of the [`fetchClosure`](@docroot@/language/builtins.md#builtins-fetchClosure) built-in function in the Nix language. + )", + }, + { + .tag = Xp::ReplFlake, + .name = "repl-flake", + .description = R"( + Allow passing [installables](@docroot@/command-ref/new-cli/nix.md#installables) to `nix repl`, making its interface consistent with the other experimental commands. + )", + }, + { + .tag = Xp::AutoAllocateUids, + .name = "auto-allocate-uids", + .description = R"( + Allows Nix to automatically pick UIDs for builds, rather than creating + `nixbld*` user accounts. See the [`auto-allocate-uids`](#conf-auto-allocate-uids) setting for details. + )", + }, + { + .tag = Xp::Cgroups, + .name = "cgroups", + .description = R"( + Allows Nix to execute builds inside cgroups. See + the [`use-cgroups`](#conf-use-cgroups) setting for details. + )", + }, + { + .tag = Xp::DiscardReferences, + .name = "discard-references", + .description = R"( + Allow the use of the [`unsafeDiscardReferences`](@docroot@/language/advanced-attributes.html#adv-attr-unsafeDiscardReferences) attribute in derivations + that use [structured attributes](@docroot@/language/advanced-attributes.html#adv-attr-structuredAttrs). This disables scanning of outputs for + runtime dependencies. + )", + }, + { + .tag = Xp::NixTesting, + .name = "nix-testing", + .description = R"( + A "permanent" experimental feature for extra features we just need + for testing. Not actually an "experiment" in the sense of being + prospective functionality for regular users. + )", + }, +}}; + +static_assert( + []() constexpr { + for (auto [index, feature] : enumerate(xpFeatureDetails)) + if (index != (size_t)feature.tag) + return false; + return true; + }(), + "array order does not match enum tag order"); + const std::optional<ExperimentalFeature> parseExperimentalFeature(const std::string_view & name) { using ReverseXpMap = std::map<std::string_view, ExperimentalFeature>; - static auto reverseXpMap = []() - { + static std::unique_ptr<ReverseXpMap> reverseXpMap = []() { auto reverseXpMap = std::make_unique<ReverseXpMap>(); - for (auto & [feature, name] : stringifiedXpFeatures) - (*reverseXpMap)[name] = feature; + for (auto & xpFeature : xpFeatureDetails) + (*reverseXpMap)[xpFeature.name] = xpFeature.tag; return reverseXpMap; }(); @@ -38,20 +226,27 @@ const std::optional<ExperimentalFeature> parseExperimentalFeature(const std::str return std::nullopt; } -std::string_view showExperimentalFeature(const ExperimentalFeature feature) +std::string_view showExperimentalFeature(const ExperimentalFeature tag) +{ + assert((size_t)tag < xpFeatureDetails.size()); + return xpFeatureDetails[(size_t)tag].name; +} + +nlohmann::json documentExperimentalFeatures() { - const auto ret = get(stringifiedXpFeatures, feature); - assert(ret); - return *ret; + StringMap res; + for (auto & xpFeature : xpFeatureDetails) + res[std::string { xpFeature.name }] = + trim(stripIndentation(xpFeature.description)); + return (nlohmann::json) res; } std::set<ExperimentalFeature> parseFeatures(const std::set<std::string> & rawFeatures) { std::set<ExperimentalFeature> res; - for (auto & rawFeature : rawFeatures) { + for (auto & rawFeature : rawFeatures) if (auto feature = parseExperimentalFeature(rawFeature)) res.insert(*feature); - } return res; } diff --git a/src/libutil/experimental-features.hh b/src/libutil/experimental-features.hh index 6a3c929df..c41f73fa0 100644 --- a/src/libutil/experimental-features.hh +++ b/src/libutil/experimental-features.hh @@ -11,8 +11,9 @@ namespace nix { /** * The list of available experimental features. * - * If you update this, don’t forget to also change the map defining their - * string representation in the corresponding `.cc` file. + * If you update this, don’t forget to also change the map defining + * their string representation and documentation in the corresponding + * `.cc` file as well. */ enum struct ExperimentalFeature { @@ -27,11 +28,6 @@ enum struct ExperimentalFeature AutoAllocateUids, Cgroups, DiscardReferences, - - /** - * A "permanent" experimental feature for extra features we just - * need for testing. - **/ NixTesting, }; @@ -40,26 +36,52 @@ enum struct ExperimentalFeature */ using Xp = ExperimentalFeature; +/** + * Parse an experimental feature (enum value) from its name. Experimental + * feature flag names are hyphenated and do not contain spaces. + */ const std::optional<ExperimentalFeature> parseExperimentalFeature( const std::string_view & name); + +/** + * Show the name of an experimental feature. This is the opposite of + * parseExperimentalFeature(). + */ std::string_view showExperimentalFeature(const ExperimentalFeature); +/** + * Compute the documentation of all experimental features. + * + * See `doc/manual` for how this information is used. + */ +nlohmann::json documentExperimentalFeatures(); + +/** + * Shorthand for `str << showExperimentalFeature(feature)`. + */ std::ostream & operator<<( std::ostream & str, const ExperimentalFeature & feature); /** - * Parse a set of strings to the corresponding set of experimental features, - * ignoring (but warning for) any unkwown feature. + * Parse a set of strings to the corresponding set of experimental + * features, ignoring (but warning for) any unknown feature. */ std::set<ExperimentalFeature> parseFeatures(const std::set<std::string> &); +/** + * An experimental feature was required for some (experimental) + * operation, but was not enabled. + */ class MissingExperimentalFeature : public Error { public: + /** + * The experimental feature that was required but not enabled. + */ ExperimentalFeature missingFeature; - MissingExperimentalFeature(ExperimentalFeature); + MissingExperimentalFeature(ExperimentalFeature missingFeature); }; /** diff --git a/src/libutil/util.hh b/src/libutil/util.hh index 56160baaf..85ab77b1b 100644 --- a/src/libutil/util.hh +++ b/src/libutil/util.hh @@ -916,16 +916,16 @@ constexpr auto enumerate(T && iterable) { size_t i; TIter iter; - bool operator != (const iterator & other) const { return iter != other.iter; } - void operator ++ () { ++i; ++iter; } - auto operator * () const { return std::tie(i, *iter); } + constexpr bool operator != (const iterator & other) const { return iter != other.iter; } + constexpr void operator ++ () { ++i; ++iter; } + constexpr auto operator * () const { return std::tie(i, *iter); } }; struct iterable_wrapper { T iterable; - auto begin() { return iterator{ 0, std::begin(iterable) }; } - auto end() { return iterator{ 0, std::end(iterable) }; } + constexpr auto begin() { return iterator{ 0, std::begin(iterable) }; } + constexpr auto end() { return iterator{ 0, std::end(iterable) }; } }; return iterable_wrapper{ std::forward<T>(iterable) }; diff --git a/src/nix/main.cc b/src/nix/main.cc index f943f77bb..705061d25 100644 --- a/src/nix/main.cc +++ b/src/nix/main.cc @@ -375,6 +375,11 @@ void mainWrapped(int argc, char * * argv) return; } + if (argc == 2 && std::string(argv[1]) == "__dump-xp-features") { + logger->cout(documentExperimentalFeatures().dump()); + return; + } + Finally printCompletions([&]() { if (completions) { |