Vaadin 20 Gradle 插件：vaadinBuildFrontend 因“参数‘outputDirectory’%s提供的路径不是目录而失败”

如何解决Vaadin 20 Gradle 插件：vaadinBuildFrontend 因“参数‘outputDirectory’%s提供的路径不是目录而失败”

在相当简单的 Vaadin 20.0.3 项目中运行 ./gradlew vaadinBuildFrontend --stacktrace 导致

[...]
Caused by: com.vaadin.flow.server.ExecutionFailedException: Error occured during goal execution: Could not write exported web component module because of exception: Path provided by parameter 'outputDirectory' (PROJECT/SUBPROJECT/build/frontend) is not a directoryPlease run Maven with the -e switch (or Gradle with the --stacktrace switch),to learn the full stack trace.
        at com.vaadin.flow.plugin.base.BuildFrontendUtil.runNodeUpdater(BuildFrontendUtil.java:307)
        at com.vaadin.gradle.VaadinBuildFrontendTask.vaadinBuildFrontend(VaadinBuildFrontendTask.kt:73)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:104)
        ... 119 more
Caused by: java.lang.RuntimeException: Could not write exported web component module because of exception: Path provided by parameter 'outputDirectory' (PROJECT/SUBPROJECTe/build/frontend) is not a directory
        at com.vaadin.flow.server.webcomponent.WebComponentModulesWriter$DirectoryWriter.generateWebComponentsToDirectory(WebComponentModulesWriter.java:264)
        at com.vaadin.flow.server.frontend.FrontendWebComponentGenerator.generateWebComponents(FrontendWebComponentGenerator.java:95)
        at com.vaadin.flow.server.frontend.NodeTasks.<init>(NodeTasks.java:597)
        at com.vaadin.flow.server.frontend.NodeTasks.<init>(NodeTasks.java:54)
        at com.vaadin.flow.server.frontend.NodeTasks$Builder.build(NodeTasks.java:215)
        at com.vaadin.flow.plugin.base.BuildFrontendUtil.runNodeUpdater(BuildFrontendUtil.java:300)
        ... 121 more
Caused by: java.lang.IllegalArgumentException: Path provided by parameter 'outputDirectory' (PROJECT/SUBPROJECT/build/frontend) is not a directory
        at com.vaadin.flow.server.webcomponent.WebComponentModulesWriter.writeWebComponentsToDirectory(WebComponentModulesWriter.java:91)
        at com.vaadin.flow.server.webcomponent.WebComponentModulesWriter$DirectoryWriter.generateWebComponentsToDirectory(WebComponentModulesWriter.java:250)
        ... 126 more

vaadin 的配置关闭不配置任何目录，所以插件应该使用默认值：

vaadin {
    optimizeBundle = false
    productionMode = false
    pnpmEnable = true
}

在运行任务之前创建 build/frontend 目录没有帮助。它在异常之前被删除。

解决方法

https://github.com/vaadin/flow/issues/8033 票听起来很相似。您可以尝试使用 --dry-run 运行 Gradle 以查看 vaadinPrepareFrontend 任务是否已运行吗？

由于这看起来像是一个错误，最好的做法是在 https://github.com/vaadin/flow/issues 打开错误报告。

另外，请阅读有关如何在多项目构建中使用 Vaadin Gradle 插件的信息：https://github.com/vaadin/vaadin-gradle-plugin/#multi-project-builds