vaadin-testbench throws IllegalStateException: Webpack exited prematurely

Flow
1

Hello,
I’m trying to use vaadin-techbench the first time. But when I add the dependency to my vaadin spring project, the Webpack isn’t alive.
(Vaadin 14.4.1; springframework.boot=2.3.2.RELEASE)
I only added the dependency

<dependency>
      <groupId>com.vaadin</groupId>
      <artifactId>vaadin-testbench</artifactId>
</dependency>

and then while running a SpringBootTest, in the webbrowser I only get a white page that shows ‘Whitelabel Error Page’.
And the logging shows me following Stacktrace:

java.lang.IllegalStateException: Webpack exited prematurely
	at com.vaadin.flow.server.DevModeHandler.doStartWebpack(DevModeHandler.java:637)
	at com.vaadin.flow.server.DevModeHandler.doStartDevModeServer(DevModeHandler.java:563)
	at com.vaadin.flow.server.DevModeHandler.runOnFutureComplete(DevModeHandler.java:510)
	at com.vaadin.flow.server.DevModeHandler.lambda$new$0(DevModeHandler.java:141)
	at java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:760)
	at java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:736)
	at java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:443)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

Is there something else I have to configurate for Webpack and vaadin-techbench?
Regards,
Thorsten

2

Based on a quick search, the issue might be related to a faulty webpack.config.js. See https://github.com/vaadin/flow/issues/7472.

3

Tarek Oraby:
Based on a quick search, the issue might be related to a faulty webpack.config.js. See https://github.com/vaadin/flow/issues/7472.

Thanks for your help, but I think it has nothing to do with the webpack.config.js. Because my Application works fine without the vaadin-techbench dependency and the webpack.config.js doesnt change when I add the dependency or not.

4

Perhaps the troubleshooting steps mentioned here would be helpful: https://mvysny.github.io/Vaadin-troubleshooting/

5

Now I have checked all dependencies from vaadin-techbench.
So I added the vaadin-testbench dependency and excluded all dependencies that vaadin-testbench uses.
Then I have removed one exclusion by one. And endet up with this.

<dependency>
  <groupId>com.vaadin</groupId>
  <artifactId>vaadin-testbench</artifactId>
  <scope>test</scope>
  <exclusions>
	<exclusion>
	  <groupId>com.vaadin</groupId>
	  <artifactId>vaadin-accordion-testbench</artifactId>
	</exclusion>
	<exclusion>
	  <groupId>com.vaadin</groupId>
	  <artifactId>vaadin-app-layout-testbench</artifactId>
	</exclusion>
	<exclusion>
	  <groupId>com.vaadin</groupId>
	  <artifactId>vaadin-board-testbench</artifactId>
	</exclusion>
	<exclusion>
	  <groupId>com.vaadin</groupId>
	  <artifactId>vaadin-charts-testbench</artifactId>
	</exclusion>
	<exclusion>
	  <groupId>com.vaadin</groupId>
	  <artifactId>vaadin-checkbox-testbench</artifactId>
	</exclusion>
	<exclusion>
	  <groupId>com.vaadin</groupId>
	  <artifactId>vaadin-combo-box-testbench</artifactId>
	</exclusion>
	<exclusion>
	  <groupId>com.vaadin</groupId>
	  <artifactId>vaadin-confirm-dialog-testbench</artifactId>
	</exclusion>
  </exclusions>
</dependency>

Now it work for me and I dont have the ‘IllegalStateException’ from above.
I dont know why, but for now it works.