Stabilize the "nix-command" feature

doc/manual/generate-manpage.nix

@@ -36,11 +36,6 @@ let
     let
 
       result = ''
-        > **Warning** \
-        > This program is
-        > [**experimental**](@docroot@/contributing/experimental-features.md#xp-feature-nix-command)
-        > and its interface is subject to change.
-
         # Name
 
         `${command}` - ${details.description}

src/libstore/build/derivation-goal.cc

@@ -994,9 +994,7 @@ void DerivationGoal::buildDone()
                     msg += line;
                     msg += "\n";
                 }
-                auto nixLogCommand = experimentalFeatureSettings.isEnabled(Xp::NixCommand)
-                    ? "nix log"
-                    : "nix-store -l";
+                auto nixLogCommand = "nix log";
                 msg += fmt("For full logs, run '" ANSI_BOLD "%s %s" ANSI_NORMAL "'.",
                     nixLogCommand,
                     worker.store.printStorePath(drvPath));

src/libutil/args.cc

@@ -583,7 +583,7 @@ Strings argvToStrings(int argc, char * * argv)
 
 std::optional<ExperimentalFeature> Command::experimentalFeature ()
 {
-    return { Xp::NixCommand };
+    return {};
 }
 
 MultiCommand::MultiCommand(std::string_view commandName, const Commands & commands_)

src/libutil/experimental-features.cc

@@ -86,15 +86,6 @@ constexpr std::array<ExperimentalFeatureDetails, numXpFeatures> xpFeatureDetails
         )",
         .trackingUrl = "https://github.com/NixOS/nix/milestone/31",
     },
-    {
-        .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.
-        )",
-        .trackingUrl = "https://github.com/NixOS/nix/milestone/28",
-    },
     {
         .tag = Xp::GitHashing,
         .name = "git-hashing",
@@ -302,7 +293,7 @@ static_assert(
  * A set of previously experimental features that are now considered
  * stable. We don't warn if users have these in `experimental-features`.
  */
-std::set<std::string> stabilizedFeatures{"flakes"};
+std::set<std::string> stabilizedFeatures{"flakes", "nix-command"};
 
 const std::optional<ExperimentalFeature> parseExperimentalFeature(const std::string_view & name)
 {

src/libutil/experimental-features.hh

@@ -20,7 +20,6 @@ enum struct ExperimentalFeature
     CaDerivations,
     ImpureDerivations,
     FetchTree,
-    NixCommand,
     GitHashing,
     RecursiveNix,
     NoUrlLiterals,

src/nix/main.cc

@@ -120,7 +120,6 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs, virtual RootArgs
             .description = "Print full build logs on standard error.",
             .category = loggingCategory,
             .handler = {[&]() { logger->setPrintBuildLogs(true); }},
-            .experimentalFeature = Xp::NixCommand,
         });
 
         addFlag({
@@ -136,7 +135,6 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs, virtual RootArgs
             .description = "Disable substituters and consider all previously downloaded files up-to-date.",
             .category = miscCategory,
             .handler = {[&]() { useNet = false; }},
-            .experimentalFeature = Xp::NixCommand,
         });
 
         addFlag({
@@ -144,7 +142,6 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs, virtual RootArgs
             .description = "Consider all previously downloaded files out-of-date.",
             .category = miscCategory,
             .handler = {[&]() { refresh = true; }},
-            .experimentalFeature = Xp::NixCommand,
         });
     }
 

tests/functional/config.sh

@@ -54,8 +54,8 @@ var=$(nix config show | grep '^allowed-uris =' | cut -d '=' -f 2 | xargs)
 
 # Test that we can !include a file.
 export NIX_USER_CONF_FILES=$here/config/nix-with-bang-include.conf
-var=$(nix config show | grep '^experimental-features =' | cut -d '=' -f 2 | xargs)
-[[ $var == nix-command ]]
+var=$(nix config show | grep '^fsync-metadata =' | cut -d '=' -f 2 | xargs)
+[[ $var == true ]]
 
 # Test that it's possible to load config from the environment
 prev=$(nix config show | grep '^cores' | cut -d '=' -f 2 | xargs)

tests/functional/config/nix-with-bang-include.conf

@@ -1,2 +1,2 @@
-experimental-features = nix-command
+fsync-metadata = true
 !include ./missing-extra-config.conf

tests/functional/experimental-features.sh

@@ -79,12 +79,3 @@ nix --experimental-features '' --help 1>/dev/null
 nix --experimental-features '' doctor --help 1>/dev/null
 nix --experimental-features '' repl --help 1>/dev/null
 nix --experimental-features '' upgrade-nix --help 1>/dev/null
-
-# These 3 arguments are currently given to all commands, which is wrong (as not
-# all care). To deal with fixing later, we simply make them require the
-# nix-command experimental features --- it so happens that the commands we wish
-# stabilizing to do not need them anyways.
-for arg in '--print-build-logs' '--offline' '--refresh'; do
-    nix --experimental-features 'nix-command' "$arg" --help 1>/dev/null
-    expect 1 nix --experimental-features '' "$arg" --help 1>/dev/null
-done