[POM-leading for DSLs] Dynamic capabilities

rascal-lsp/src/main/java/org/rascalmpl/vscode/lsp/parametric/ParametricTextDocumentService.java

@@ -1013,10 +1013,14 @@ private static String buildContributionKey(LanguageParameter lang) {
         return lang.getMainFunction() + "::" + lang.getMainFunction();
     }
 
+    public static boolean isLanguageCompletelyRemoved(LanguageParameter lang) {
+        return lang.getMainModule() == null || lang.getMainModule().isEmpty();
+    }
+
     @Override
     public synchronized void unregisterLanguage(LanguageParameter lang) {
         logger.info("unregisterLanguage({})", lang.getName());
-        boolean removeAll = lang.getMainModule() == null || lang.getMainModule().isEmpty();
+        boolean removeAll = isLanguageCompletelyRemoved(lang);
         if (!removeAll) {
             var contrib = contributions.get(lang.getName());
             if (contrib != null && !contrib.removeContributor(buildContributionKey(lang))) {

rascal-lsp/src/main/java/org/rascalmpl/vscode/lsp/parametric/capabilities/AbstractDynamicCapability.java

@@ -150,7 +150,8 @@ public boolean equals(@Nullable Object obj) {
         }
         var other = (AbstractDynamicCapability<?>) obj;
         return Objects.equals(id, other.id)
-            && Objects.equals(methodName, other.methodName);
+            && Objects.equals(methodName, other.methodName)
+            && Objects.equals(preferStaticRegistration, other.preferStaticRegistration);
     }
 
     @Override

rascal-lsp/src/main/java/org/rascalmpl/vscode/lsp/parametric/capabilities/CapabilityRegistration.java

@@ -75,6 +75,8 @@
     private final Set<AbstractDynamicCapability<?>> staticCapabilities;
 
     private final AtomicReference<Collection<ICapabilityParams>> lastParams = new AtomicReference<>(Collections.emptyList());
+    private final AtomicReference<CompletableFuture<Void>> currentUpdate;
+
     // Map of method names with current registration values
     private final Map<String, Registration> currentRegistrations = new ConcurrentHashMap<>();
 
@@ -87,6 +89,7 @@
         this.client = client;
         this.exec = exec;
         this.noop = CompletableFutureUtils.completedFuture(null, exec);
+        this.currentUpdate = new AtomicReference<>(noop);
 
         // Check whether to register capabilities dynamically or statically
         var dynamicCaps = new HashSet<AbstractDynamicCapability<?>>();
@@ -120,16 +123,19 @@
      * @return A future that completes with a boolean that is false when any registration failed, and true otherwise.
      */
     public CompletableFuture<Void> update(Collection<ICapabilityParams> languages) {
-        logger.debug("Updating {} dynamic capabilities for {} languages", dynamicCapabilities.size(), languages.size());
         // Copy the contributions so we know we are looking at a stable collection of elements.
-
         /*
             *VERY IMPORTANT* Setting the atomic reference from the thread that called us.
             We need to be sure that the `lastContributions` reference actually points to the most recently known contributions.
             Therefore, we need to set this reference before delegating any work to futures, where we lose guaranteed execution order.
             Additionally, this function should be called from a thread pool with predictable execution order.
         */
         lastParams.set(List.copyOf(languages));
+        return currentUpdate.updateAndGet(current -> current.thenComposeAsync(v -> doUpdate(languages), exec));
+    }
+
+    private CompletableFuture<Void> doUpdate(Collection<ICapabilityParams> languages) {
+        logger.debug("Updating {} dynamic capabilities for {} languages", dynamicCapabilities.size(), languages.size());
         return CompletableFutureUtils.reduce(dynamicCapabilities.stream().map(this::updateRegistration), exec)
             .thenAccept(_v -> logger.debug("Done updating dynamic capabilities"));
     }
@@ -200,6 +206,7 @@
                     result = register(registration, existingRegistration);
                 }
 
+                // TODO Check/Fix that if one capability fails, the rest are still registered
                 return result.handle((_v, t) -> {
                     if (t != null) {
                         // An error occurred. Inform the user and do not recurse.

rascal-lsp/src/main/java/org/rascalmpl/vscode/lsp/parametric/routing/ActualRoutingLanguageServer.java

@@ -113,7 +113,7 @@ public class ActualRoutingLanguageServer extends BaseLanguageServer.ActualLangua
     private final Map<String, CompletableFuture<IBaseLanguageServerExtensions>> languageServers = new ConcurrentHashMap<>();
     private final Map<String, String> languagesByExtension = new ConcurrentHashMap<>();
 
-    private final MultipleClientProxy client = new MultipleClientProxy();
+    private @MonotonicNonNull MultipleClientProxy remoteClient;
     private @MonotonicNonNull InitializeParams initializeParams;
     private final JsonWriter logForwarder;
 
@@ -173,7 +173,7 @@ public CompletableFuture<IBaseLanguageServerExtensions> route(ISourceLocation lo
     @Override
     public void connect(LanguageClient client) {
         super.connect(client); // first let the super class proxy the client
-        this.client.connect(availableClient());
+        this.remoteClient = new MultipleClientProxy(availableClient(), getExecutor());
     }
 
     private static String extension(ISourceLocation doc) {
@@ -349,6 +349,11 @@ public void write(JsonWriter writer, ProxiedIValue proxiedValue) throws IOExcept
     }
 
     private @Nullable CompletableFuture<IBaseLanguageServerExtensions> startServer(LanguageParameter lang) {
+        if (remoteClient == null) {
+            // This should never happen, since it's initialized by `connect` before we are able to receive any `registerLanguage` requests.
+            throw new IllegalStateException("Remote client is not initialized");
+        }
+
         var serverParams = BaseLanguageServer.DEPLOY_MODE
             ? startServerProcess(lang)
             : connectToServer(lang)
@@ -360,7 +365,7 @@ public void write(JsonWriter writer, ProxiedIValue proxiedValue) throws IOExcept
 
         var serverLauncher = new Launcher.Builder<IBaseLanguageServerExtensions>()
             .setRemoteInterface(IBaseLanguageServerExtensions.class)
-            .setLocalService(client)
+            .setLocalService(remoteClient)
             .setInput(serverParams.getLeft())
             .setOutput(serverParams.getMiddle())
             .configureGson(ActualRoutingLanguageServer::configureProxyGson)
@@ -468,27 +473,23 @@ public synchronized CompletableFuture<Void> sendRegisterLanguage(LanguageParamet
     public synchronized CompletableFuture<Void> sendUnregisterLanguage(LanguageParameter lang) {
         logger.debug("rascal/sendUnregisterLanguage({})", lang.getName());
 
-        var work = route(lang.getName())
-            .thenCompose(s -> s.sendUnregisterLanguage(lang));
-
-        // Note: this should be handled for the deployed scenario by the process onExit hook.
-        boolean removeAll = lang.getMainModule() == null || lang.getMainModule().isEmpty();
-        if (removeAll) {
-            // clear the whole language
-            logger.trace("unregisterLanguage({}) completely", lang.getName());
+        if (ParametricTextDocumentService.isLanguageCompletelyRemoved(lang)) {
+            // Do not remove the connection to the server.
+            // For the deployed scenario, this is handled by the process onExit hook.
+            // For the development scenario, we maintain the connection, since the remote server does not exit.
 
             for (var extension : lang.getExtensions()) {
                 this.languagesByExtension.remove(extension);
             }
-            var removed = languageServers.remove(lang.getName());
-            if (removed != null) {
-                work = work
-                    .thenCompose(ignored -> removed)
-                    .thenCompose(server -> server.shutdown().thenAccept(ignored -> server.exit()));
-            }
         }
 
-        return work;
+        return route(lang.getName()).handle((s, t) -> {
+            if (s == null) {
+                // Nothing to unregister
+                return CompletableFutureUtils.<Void>completedFuture(null, getExecutor());
+            }
+            return s.sendUnregisterLanguage(lang);
+        }).thenCompose(Function.identity());
     }
 
     @Override