nix-testing -> daemon-trust-override

And only enable in the tests that need it. This makes it less of a
sledgehammer.

src/libutil/experimental-features.cc

@@ -190,12 +190,13 @@ constexpr std::array<ExperimentalFeatureDetails, 12> xpFeatureDetails = {{
         )",
     },
     {
-        .tag = Xp::NixTesting,
-        .name = "nix-testing",
+        .tag = Xp::DaemonTrustOverride,
+        .name = "daemon-trust-override",
         .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.
+            Allow forcing trusting or not trusting clients with
+            `nix-daemon`. This is useful for testing, but possibly also
+            useful for various experiments with `nix-daemon --stdio`
+            networking.
         )",
     },
 }};

src/libutil/experimental-features.hh

@@ -28,7 +28,7 @@ enum struct ExperimentalFeature
     AutoAllocateUids,
     Cgroups,
     DiscardReferences,
-    NixTesting,
+    DaemonTrustOverride,
 };
 
 /**

src/nix/daemon.cc

@@ -472,13 +472,13 @@ static int main_nix_daemon(int argc, char * * argv)
             else if (*arg == "--stdio")
                 stdio = true;
             else if (*arg == "--force-trusted") {
-                experimentalFeatureSettings.require(Xp::NixTesting);
+                experimentalFeatureSettings.require(Xp::DaemonTrustOverride);
                 isTrustedOpt = Trusted;
             } else if (*arg == "--force-untrusted") {
-                experimentalFeatureSettings.require(Xp::NixTesting);
+                experimentalFeatureSettings.require(Xp::DaemonTrustOverride);
                 isTrustedOpt = NotTrusted;
             } else if (*arg == "--default-trust") {
-                experimentalFeatureSettings.require(Xp::NixTesting);
+                experimentalFeatureSettings.require(Xp::DaemonTrustOverride);
                 isTrustedOpt = std::nullopt;
             } else return false;
             return true;

tests/build-remote-trustless-should-fail-0.sh

@@ -1,5 +1,9 @@
 source common.sh
 
+enableFeatures "daemon-trust-override"
+
+restartDaemon
+
 [[ $busybox =~ busybox ]] || skipTest "no busybox"
 
 unset NIX_STORE_DIR

tests/build-remote-trustless-should-pass-2.sh

@@ -1,5 +1,9 @@
 source common.sh
 
+enableFeatures "daemon-trust-override"
+
+restartDaemon
+
 # Remote doesn't trust us
 file=build-hook.nix
 prog=$(readlink -e ./nix-daemon-untrusting.sh)

tests/build-remote-trustless-should-pass-3.sh

@@ -1,5 +1,9 @@
 source common.sh
 
+enableFeatures "daemon-trust-override"
+
+restartDaemon
+
 # Remote doesn't trusts us, but this is fine because we are only
 # building (fixed) CA derivations.
 file=build-hook-ca-fixed.nix

tests/init.sh

@@ -20,7 +20,7 @@ cat > "$NIX_CONF_DIR"/nix.conf <<EOF
 build-users-group =
 keep-derivations = false
 sandbox = false
-experimental-features = nix-command flakes nix-testing
+experimental-features = nix-command flakes
 gc-reserved-space = 0
 substituters =
 flake-registry = $TEST_ROOT/registry.json