build (mvn install) of new application takes forever - vaadin

Question

I was trying to use an existing application as starting point for a new one.
So, I copied over the src-folder, the pom and a couple of IDE-specific files config files.
I then refactored all giving it a new path and application name and then I wanted to do a first build and entered mvn install.
This process is now hanging since 1 1/2 hours in vaadin-maven-plugin:18.0.2:build-frontend (see full console output below).
Is this expected or why is this taking so long? Can I somehow figure out, why and where this is hanging?
What am I missing? Are there any files other then those mentioned that absolutely MUST exist before a new Vaadin application can (even be tried to) be built?
[INFO] Scanning for projects...
[INFO]
[INFO] --------------< ch.zh.ksta.monitoring:my_app >---------------
[INFO] Building KStA-ZH-Monitoring 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) # my_app ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] Copying 7 resources
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) # my_app ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- vaadin-maven-plugin:18.0.2:prepare-frontend (default) # my_app ---
[INFO] writing file D:\Projects\my_app\target\flow-frontend\package.json.
[INFO] writing file D:\Projects\my_app\target\flow-frontend\form\package.json.
[INFO] writing file 'D:\Projects\my_app\target\index.html'
[INFO] writing file 'D:\Projects\my_app\target\index.ts'
[INFO] Copying frontend resources from jar files ...
[INFO] Visited 173 resources. Took 2229 ms.
[INFO]
[INFO] --- vaadin-maven-plugin:18.0.2:build-frontend (default) # my_app ---
[INFO] Scanning classes to find frontend configurations and dependencies...
[INFO] Visited 720 classes. Took 2553 ms.
[INFO] Visited 126 classes. Took 138 ms.
[INFO] writing file D:\Projects\my_app\target\flow-frontend\package.json.
[INFO] writing file D:\Projects\my_app\target\flow-frontend\form\package.json.
[INFO] writing file 'D:\Projects\my_app\target\index.html'
[INFO] writing file 'D:\Projects\my_app\target\index.ts'
[INFO] Parsing java files from [D:\Projects\my_app\src\main\java]
[INFO] There are no connect endpoints to generate.
[INFO] Running `pnpm install` to resolve and optionally download frontend dependencies. This may take a moment, please stand by...
[INFO] Generated pnpmfile hook file: 'D:\Projects\my_app\pnpmfile.js'
[INFO] installing pnpm version 4.4.0 locally
[INFO] using 'C:\Users\mmo\.vaadin\node\node.exe C:\Users\mmo\.vaadin\node_modules\pnpm\bin\pnpm.js' for frontend package installation
Later addition:
If I terminate this using ^C I get:
...
2021-05-31 18:24:40,199 ERROR [task-1] com.vaadin.flow.server.frontend.TaskRunNpmInstall: Command `C:\Program Files\nodejs\node.exe C:\Users\mmo\.vaadin\node_modules\pnpm\bin\pnpm.js --shamefully-hoist=true install` failed:
Using hooks from: D:\Projects\my_app\pnpmfile.jsreadPackage hook is declared. Manifests of dependencies might get overridden
2021-05-31 18:24:40,201 ERROR [task-1] com.vaadin.flow.server.frontend.TaskRunNpmInstall: >>> Dependency ERROR. Check that all required dependencies are deployed in pnpm repositories.
2021-05-31 18:24:40,205 DEBUG [task-1] com.vaadin.flow.server.startup.DevModeInitializer: Could not initialize dev mode handler. One of the node tasks failed
com.vaadin.flow.server.ExecutionFailedException: Pnpm install has exited with non zero status. Some dependencies are not installed. Check pnpm command output
at com.vaadin.flow.server.frontend.TaskRunNpmInstall.runNpmInstall(TaskRunNpmInstall.java:405)
at com.vaadin.flow.server.frontend.TaskRunNpmInstall.execute(TaskRunNpmInstall.java:120)
at com.vaadin.flow.server.frontend.NodeTasks.execute(NodeTasks.java:634)
at com.vaadin.flow.server.startup.DevModeInitializer.runNodeTasks(DevModeInitializer.java:471)
at com.vaadin.flow.server.startup.DevModeInitializer.lambda$initDevModeHandler$0(DevModeInitializer.java:381)
at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1736)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:829)
If I restart the build again it will hang again.
Gee - is this brittle... :-(

Answer 1

Got this same error. I deleted from my home directory:
.vaadin
.pnpm-store
... and the generated stuff from my project:
webpack.config.js
tsconfig.json
types.d.ts
webpack.config.js
webpack.generated.js
pnpm-lock.yaml
pnpmfile.js
package.json
.npmrc
target
.pnpm-debug.log
... probably overkill, but then it worked again.