fix(engine-core): always consume Process output

packages/java/engine-core/src/main/java/com/vaadin/hilla/engine/GeneratorProcessor.java

@@ -190,8 +190,10 @@ private Path getTsgenPath() {
             var runner = new GeneratorShellRunner(baseDir.toFile(), nodeCommand,
                     arguments);
             runner.run(null, (stdOutStream) -> {
-                new BufferedReader(new InputStreamReader(stdOutStream)).lines()
-                        .limit(1).forEach(pathLine::set);
+                // Consume all output from Node
+                var lines = new BufferedReader(
+                        new InputStreamReader(stdOutStream)).lines().toList();
+                lines.stream().limit(1).forEach(pathLine::set);
             }, null);
             if (pathLine.get() == null) {
                 throw new CommandRunnerException("No output from Node");

packages/java/engine-core/src/main/java/com/vaadin/hilla/engine/commandrunner/CommandRunner.java

@@ -1,6 +1,7 @@
 package com.vaadin.hilla.engine.commandrunner;
 
 import com.vaadin.flow.server.frontend.FrontendUtils;
+import org.apache.commons.io.IOUtils;
 import org.slf4j.Logger;
 
 import java.io.*;
@@ -178,12 +179,18 @@ private void executeCommand(String executable, String[] arguments,
                     .of(new Pipe<>(stdOut, process.getInputStream()),
                             new Pipe<>(stdErr, process.getErrorStream()),
                             new Pipe<>(stdIn, process.getOutputStream()))
-                    .filter(handler -> handler.consumer() != null)
                     .map(handler -> {
                         var t = new Thread(() -> {
-                            try (var stream = handler.stream()) {
-                                ((Consumer<Closeable>) handler.consumer())
-                                        .accept(stream);
+                            var stream = handler.stream();
+                            try {
+                                if (handler.consumer() != null) {
+                                    ((Consumer<Closeable>) handler.consumer())
+                                            .accept(stream);
+                                } else if (stream instanceof InputStream inputStream) {
+                                    // make sure the stream is consumed
+                                    // to avoid deadlock
+                                    IOUtils.consume(inputStream);
+                                }
                             } catch (IOException e) {
                                 getLogger().error("Error while handling stream",
                                         e);

packages/ts/generator-plugin-client/src/index.ts

@@ -16,9 +16,14 @@ export default class ClientPlugin extends Plugin {
 
   static async #checkForCustomClientFile(path?: string): Promise<boolean> {
     const dir = path?.startsWith('file:') ? fileURLToPath(path) : path;
+    if (!dir) {
+      return false;
+    }
 
     try {
-      return !!(dir && (await open(`${dir}/${ClientPlugin.CUSTOM_CLIENT_FILE_NAME}.ts`, 'r')));
+      const fileHandle = await open(`${dir}/${ClientPlugin.CUSTOM_CLIENT_FILE_NAME}.ts`, 'r');
+      await fileHandle.close();
+      return true;
     } catch {
       return false;
     }