vaadin:clean-frontend fails with "Couldn't remove [...]\node_modules directory" on Windows

[OlliTietavainenVaadin]

Description of the bug

Running the vaadin:clean-frontend goal sometimes fails with an exception (instead of with a nice error message Failed to remove .../node_modules. Please remove it manually.) which seems to be related to not being able to delete \node_modules`.

Occasionally this error also occurs after running vaadin:clean-frontend and starting the Spring Boot application again (can't confirm whether node_modules was properly deleted in this case or not).

The exception stack trace looks as follows:

java.lang.IllegalStateException: com.vaadin.flow.server.ExecutionFailedException: Couldn't remove [...]\node_modules directory
at com.vaadin.base.devserver.AbstractDevServerRunner.getCause(AbstractDevServerRunner.java:782) ~[vaadin-dev-server-9.0.2.jar:na]
at com.vaadin.base.devserver.AbstractDevServerRunner.getCause(AbstractDevServerRunner.java:778) ~[vaadin-dev-server-9.0.2.jar:na]
at com.vaadin.base.devserver.AbstractDevServerRunner.handleRequest(AbstractDevServerRunner.java:644) ~[vaadin-dev-server-9.0.2.jar:na]
at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1567) ~[flow-server-9.0.2.jar:9.0.2]
at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:299) ~[flow-server-9.0.2.jar:9.0.2]
at com.vaadin.flow.spring.SpringServlet.service(SpringServlet.java:109) ~[vaadin-spring-19.0.2.jar:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.56.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:711) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:353) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:313) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:141) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:177) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:51) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.14.jar:5.3.14]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.56.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.14.jar:5.3.14]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.56.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:327) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:115) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:81) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:122) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:116) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:126) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:81) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:109) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:136) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:93) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:149) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:219) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:213) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:103) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:89) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:117) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:110) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:80) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:55) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:211) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:183) ~[spring-security-web-5.6.1.jar:5.6.1]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:354) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267) ~[spring-web-5.3.14.jar:5.3.14]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:96) ~[spring-boot-actuator-2.6.2.jar:2.6.2]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:769) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1732) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]
Caused by: com.vaadin.flow.server.ExecutionFailedException: Couldn't remove [...]\node_modules directory
at com.vaadin.flow.server.frontend.TaskRunNpmInstall.runNpmInstall(TaskRunNpmInstall.java:305) ~[flow-server-9.0.2.jar:9.0.2]
at com.vaadin.flow.server.frontend.TaskRunNpmInstall.execute(TaskRunNpmInstall.java:143) ~[flow-server-9.0.2.jar:9.0.2]
at com.vaadin.flow.server.frontend.NodeTasks.execute(NodeTasks.java:919) ~[flow-server-9.0.2.jar:9.0.2]
at com.vaadin.base.devserver.startup.DevModeInitializer.runNodeTasks(DevModeInitializer.java:407) ~[vaadin-dev-server-9.0.2.jar:na]
at com.vaadin.base.devserver.startup.DevModeInitializer.lambda$initDevModeHandler$0(DevModeInitializer.java:336) ~[vaadin-dev-server-9.0.2.jar:na]
at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run$$$capture(CompletableFuture.java:1804) ~[na:na]
at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java) ~[na:na]
at java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1796) ~[na:na]
at java.base/java.util.concurrent.ForkJoinTask.doExec$$$capture(ForkJoinTask.java:373) ~[na:na]
at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java) ~[na:na]
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182) ~[na:na]
at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655) ~[na:na]
at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622) ~[na:na]
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165) ~[na:na]
Caused by: java.io.IOException: Cannot delete file: [...]\node_modules
at org.apache.commons.io.FileUtils.forceDelete(FileUtils.java:1344) ~[commons-io-2.11.0.jar:2.11.0]
at com.vaadin.flow.server.frontend.TaskRunNpmInstall.cleanUp(TaskRunNpmInstall.java:532) ~[flow-server-9.0.2.jar:9.0.2]
at com.vaadin.flow.server.frontend.TaskRunNpmInstall.runNpmInstall(TaskRunNpmInstall.java:303) ~[flow-server-9.0.2.jar:9.0.2]
... 13 common frames omitted
Caused by: java.nio.file.NoSuchFileException: [...]\node_modules\.pnpm\@babel\core@7.16.5\node_modules\@babel\code-frame
at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:85) ~[na:na]
at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103) ~[na:na]
at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:108) ~[na:na]
at java.base/sun.nio.fs.WindowsDirectoryStream.<init>(WindowsDirectoryStream.java:86) ~[na:na]
at java.base/sun.nio.fs.WindowsFileSystemProvider.newDirectoryStream(WindowsFileSystemProvider.java:535) ~[na:na]
at java.base/java.nio.file.Files.newDirectoryStream(Files.java:482) ~[na:na]
at java.base/java.nio.file.FileTreeWalker.visit(FileTreeWalker.java:301) ~[na:na]
at java.base/java.nio.file.FileTreeWalker.next(FileTreeWalker.java:374) ~[na:na]
at java.base/java.nio.file.Files.walkFileTree(Files.java:2845) ~[na:na]
at java.base/java.nio.file.Files.walkFileTree(Files.java:2882) ~[na:na]
at org.apache.commons.io.file.PathUtils.visitFileTree(PathUtils.java:971) ~[commons-io-2.11.0.jar:2.11.0]
at org.apache.commons.io.file.PathUtils.deleteDirectory(PathUtils.java:434) ~[commons-io-2.11.0.jar:2.11.0]
at org.apache.commons.io.file.PathUtils.delete(PathUtils.java:391) ~[commons-io-2.11.0.jar:2.11.0]
at org.apache.commons.io.FileUtils.forceDelete(FileUtils.java:1341) ~[commons-io-2.11.0.jar:2.11.0]
... 15 common frames omitted

Expected behavior

If deleting node_modules fails, it should give a graceful error message.

Minimal reproducible example

https://github.com/OlliTietavainenVaadin/v22-flow-start

1. run mvn spring-boot:run, wait for the front-end build to finish
2. stop the process
3. run mvn vaadin:dance

Repeat the process if necessary.

The results may be a bit different depending on if these are run from the IDE or from command line (used WSL for command line for testing which gave me the exception)

Versions

• Vaadin / Flow version: Vaadin 22.0.2
• Java version: Tested with 1.8.0_191 and17+35-LTS-2724
• OS version: Windows 10
• Browser version (if applicable): n/a
• Application Server (if applicable): Spring Boot
• IDE (if applicable): IntelliJ Idea Ultimate

[mvysny]

The NoSuchFileException suggests that dirs are being deleted as the webpack/pnpm terminates, and this happens in parallel with vaadin:dance. Perhaps in this case Vaadin plugin should retry

[OlliTietavainenVaadin]

I have a vague feeling that this might be some timing / process forking issue, but I don't have any facts to back that up.

[caalador]

To be clear the vaadin:clean-frontend goal doesn't fail as it cleans everything except the node_modules forlder which for some unknown reason could not be deleted so the user is asked to remove the folder manually.

The second exception is not from the clean task, but from npm installation task that sees that there is something that needs node_modules to be removed which then fails as there is (according to the stacktrace) a file marked that doesn't exist and this can not be removed and windows throws an exception.