test: prevent ambient environment from leaking into daemon builds on CI (2.x)

client/src/main/java-mvnd/org/mvndaemon/mvnd/client/DefaultClient.java

@@ -242,6 +242,15 @@ public DefaultClient(DaemonParameters parameters) {
                 true);
     }
 
+    /**
+     * The environment forwarded to the daemon in the {@link Message.BuildRequest}. Defaults to the
+     * client's own environment; overridable so tests can run hermetically (e.g. without inheriting
+     * an ambient {@code MAVEN_ARGS}).
+     */
+    protected Map<String, String> buildRequestEnvironment() {
+        return System.getenv();
+    }
+
     @Override
     public ExecutionResult execute(ClientOutput output, List<String> argv) {
         LOGGER.debug("Starting client");
@@ -374,7 +383,7 @@ public ExecutionResult execute(ClientOutput output, List<String> argv) {
                         args,
                         parameters.userDir().toString(),
                         parameters.multiModuleProjectDirectory().toString(),
-                        System.getenv()));
+                        buildRequestEnvironment()));
 
                 output.accept(Message.buildStatus(
                         "Connected to daemon " + daemon.getDaemon().getId() + ", scanning for projects..."));

integration-tests/src/test/java/org/mvndaemon/mvnd/junit/JvmTestClient.java

@@ -21,6 +21,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -42,6 +43,18 @@ public JvmTestClient(DaemonParameters parameters) {
         this.parameters = parameters;
     }
 
+    /**
+     * Strip any ambient {@code MAVEN_ARGS} (e.g. actions/setup-java sets it to {@code -ntp}) from the
+     * environment forwarded to the daemon, so it cannot override per-test flags such as
+     * ConcurrentDownloadsTest's transfer-progress expectation. Keeps the test daemon hermetic.
+     */
+    @Override
+    protected Map<String, String> buildRequestEnvironment() {
+        final Map<String, String> env = new HashMap<>(super.buildRequestEnvironment());
+        env.remove("MAVEN_ARGS");
+        return env;
+    }
+
     @Override
     public ExecutionResult execute(ClientOutput output, List<String> argv) {
         setMultiModuleProjectDirectory(argv);

integration-tests/src/test/java/org/mvndaemon/mvnd/junit/MvndTestExtension.java

@@ -21,6 +21,7 @@
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.lang.reflect.Field;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -235,7 +236,7 @@ public static MvndResource create(
                     multiModuleProjectDirectory,
                     Paths.get(System.getProperty("java.home")).toAbsolutePath().normalize(),
                     localMavenRepository,
-                    null,
+                    createIsolatedSettings(testDir.resolve("settings.xml")),
                     TimeUtils.toDuration(Environment.MVND_IDLE_TIMEOUT.getDefault()),
                     keepAlive != null && !keepAlive.isEmpty()
                             ? TimeUtils.toDuration(keepAlive)
@@ -251,6 +252,24 @@ public static MvndResource create(
             return new MvndResource(parameters, registry, isNative, timeoutMs);
         }
 
+        /**
+         * Writes a minimal, isolated {@code settings.xml} and returns its path so that the daemon
+         * is always launched with an explicit {@code -s} and never falls back to the ambient
+         * {@code ${user.home}/.m2/settings.xml}. Without this, when running with {@code -Dmrm=false}
+         * (as CI does), the daemon reads the runner's user settings. actions/setup-java writes one
+         * containing {@code <interactiveMode>false</interactiveMode>}, which made {@code versions:set}
+         * run non-interactively and broke InteractiveTest. An empty settings keeps the defaults
+         * (interactive, no ambient mirrors) so the tests behave the same everywhere.
+         */
+        static Path createIsolatedSettings(Path settingsPath) {
+            try {
+                Files.write(settingsPath, "<settings/>\n".getBytes(StandardCharsets.UTF_8));
+            } catch (IOException e) {
+                throw new RuntimeException("Could not write " + settingsPath, e);
+            }
+            return settingsPath;
+        }
+
         private static void prefillLocalRepo(final Path localMavenRepository) {
             /* Workaround for https://github.com/apache/maven-mvnd/issues/281 */
             final String preinstallArtifacts =

integration-tests/src/test/java/org/mvndaemon/mvnd/junit/NativeTestClient.java

@@ -82,6 +82,9 @@ public ExecutionResult execute(ClientOutput output, List<String> args) throws In
                 .redirectErrorStream(true);
 
         final Map<String, String> env = builder.environment();
+        // Strip any ambient MAVEN_ARGS (e.g. actions/setup-java sets it to -ntp) so it cannot leak
+        // through the native binary into the daemon and override per-test flags. Keeps tests hermetic.
+        env.remove("MAVEN_ARGS");
         if (!Environment.MVND_HOME.hasCommandLineOption(args)) {
             env.put(Environment.MVND_HOME.getEnvironmentVariable(), Environment.MVND_HOME.asString());
         }