fix: ensure Source.findLanguage and context operations run on platform thread in PolyglotDeployer and JSInterceptorFactory to prevent thread-local issues

See #663

Author: mkjsix

polyglot/src/main/java/org/restheart/polyglot/PolyglotDeployer.java

@@ -78,9 +78,9 @@
  * @author Andrea Di Cesare {@literal <andrea@softinstigate.com>}
  */
 @RegisterPlugin(
-        name = "polyglotDeployer",
-        description = "handles GraalVM polyglot plugins",
-        enabledByDefault = true)
+    name = "polyglotDeployer",
+    description = "handles GraalVM polyglot plugins",
+    enabledByDefault = true)
 public class PolyglotDeployer implements Initializer {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(PolyglotDeployer.class);
@@ -353,14 +353,18 @@ private List<Path> findDeclaredPlugins(final Path path, final String prop, final
                         if (checkPluginFiles) {
                             if (Files.isRegularFile(pluginPath)) {
                                 try {
-                                    final var language = PolyglotClassloaderHelper.withPluginsClassloaderResult(
-                                        () -> Source.findLanguage(pluginPath.toFile()));
+                                    // Source.findLanguage() touches Truffle internals;
+                                    // this lambda may run on a virtual thread (file watcher),
+                                    // so dispatch to a platform thread (see PolyglotThreadUtils)
+                                    final var language = PolyglotThreadUtils.onPlatformThread(
+                                            () -> PolyglotClassloaderHelper.withPluginsClassloaderResult(
+                                                    () -> Source.findLanguage(pluginPath.toFile())));
                                     if ("js".equals(language)) {
                                         ret.add(pluginPath);
                                     } else {
                                         LOGGER.warn("{} is not javascript", pluginPath.toAbsolutePath());
                                     }
-                                } catch (final IOException e) {
+                                } catch (final Exception e) {
                                     LOGGER.warn("{} is not javascript", pluginPath.toAbsolutePath(), e);
                                 }
                             } else {
@@ -454,8 +458,8 @@ private void deployNodeService(final Path pluginPath) throws IOException {
                 DEPLOYEES.put(pluginPath.toAbsolutePath(), srv);
 
                 LOGGER.info(ansi().fg(GREEN).a(
-                                "Service '{}' deployed at URI '{}' with description: '{}'. Secured: {}. Uri match policy: {}")
-                                .reset().toString(), srv.name(), srv.uri(), srv.getDescription(), srv.secured(),
+                        "Service '{}' deployed at URI '{}' with description: '{}'. Secured: {}. Uri match policy: {}")
+                        .reset().toString(), srv.name(), srv.uri(), srv.getDescription(), srv.secured(),
                         srv.matchPolicy());
             } catch (IOException | InterruptedException | ExecutionException | TimeoutException ex) {
                 LOGGER.error("Error deploying node service {}", pluginPath, ex);

polyglot/src/main/java/org/restheart/polyglot/interceptors/JSInterceptorFactory.java

@@ -94,6 +94,13 @@ public JSInterceptorFactory(Optional<MongoClient> mclient, Configuration config)
             LOGGER.debug("Enabling require for interceptor {} with require-cwd {} ", pluginPath, requireCwdPath);
         }
 
+        // Source.findLanguage() and all Context/Value operations must run on a
+        // platform thread (see PolyglotThreadUtils).  The whole block is dispatched
+        // as a single task so eval() and subsequent Value member access happen on
+        // the very same thread that entered the context.
+        try {
+        return PolyglotThreadUtils.onPlatformThread(() -> {
+
         // check that the plugin script is js (use PluginsClassloader so js-language is visible)
         final var language = PolyglotClassloaderHelper.withPluginsClassloaderResult(
             () -> Source.findLanguage(pluginPath.toFile()));
@@ -107,12 +114,6 @@ public JSInterceptorFactory(Optional<MongoClient> mclient, Configuration config)
         var sindexPath = pluginPath.toUri().toString();
         LOGGER.debug("Resolved interceptor path: {}", sindexPath);
 
-        // Context creation, eval and all Value member access must happen on the very
-        // same platform thread: a Value returned by eval() is only safely readable on
-        // the thread the context is entered on (see PolyglotThreadUtils), so the whole
-        // block below -- not just the eval() calls -- is dispatched as a single task.
-        try {
-        return PolyglotThreadUtils.onPlatformThread(() -> {
         var ctx = ContextQueue.newContext(engine, "foo", config, LOGGER, mclient, "", contextOptions);
         ctx.enter();
         try {