Gradle process stop doesn't lead to node process stop

[imanushin]

Short: stopping gradle execution on Windows from command line by pressing Ctrl-C doesn't lead to stopping node.exe subprocess on Windows.

Steps to reproduce:

1. Create project with webpack
2. Configure start at package.json script via:

"scripts": {
    "start": "webpack-dev-server --open --config webpack.dev.js"
  }

3. Create npmStart task via gradle kts script:

tasks {
    val npmStart by registering(NpmTask::class) {
        /*dependent tasks are skipped for simplification*/
        setArgs(listOf("run", "start"))
    }
}

4. Start local node server via .\gradlew.bat :npmStart
5. Wait for process start (web browser opens)
6. Press Ctrl-C to stop node.exe execution

Expected result:
All child processes under gradle will be stopped.

Actual result:
Node.exe process remains. And this process starts to be zombie, e.g. process without parent.

Hint: probably (I'm not sure, this require testing), NpmTask should be inherited from Exec, not from DefaultTask. It means that args field will be inherited from Exec task, so it will be fully configurable via user. However next Gradle tool will be responsible to stop all child tasks.

[deepy]

I suspect inherting from Exec won't be enough to solve this as there's an open issue that matches this gradle/gradle#7603.

To solve it we probably need to start npm through node rather than relying on npm.cmd

[imanushin]

Agree, that problem won't be fixed just after task inheritance change. However after this change we can just wait for fix from Gradle team. E.g. for current moment issue will exist even if Gradle team fixes Exec task behavior.

[deepy]

I'm pretty sure they both share the same issue and will be fixed at the same time, but if it's only fixed in Exec it's probably going to be easy to also get that fix for project.exec.

[imanushin]

@deepy , as @philiparvidsson said here:

my bad - I edited the original post to clarify! You are correct in that it only affects bat-files.

Therefore, I can advice the following solutions:

• Use ps1 file from npm installation (e.g. npm.ps1, instead of npm.bat).
• Re-implement content of npm.cmd file inside the plugin. It means that we start node executable directly, without cmd shell in the middle.

[deepy]

Pretty sure that'd have the same issue. gradle/gradle#7603 (comment)

Thank you for the elaborate investigation! So we'd see similar issues if a program forked with exec() forked another program on Windows. cmd is just a common example of this situation.

[atali]

Any update on that issue ?

[deepy]

This really depends on the linked Gradle issue, which sounds like it should be easy to do with Java 9+.

The best way to get this fixed would be to send a PR to Gradle

[jGleitz]

Hi! The referenced Gradle issue only relates to Windows. However, I am also experiencing this bug on Linux: When I stop the Gradle task serving my docz site, the node processes are not killed. Does this mean that the Gradle issue also applies to Linux or might there be something that can be fixed in this plugin?

[deepy]

I might be wrong here, but I was under the impression that it applied to all operating systems.
At least I've seen similar issues on macOS and Linux

[jGleitz]

Hm, seems you are right. The original issue stated that

NOTE 1: This seems to affect Windows only!

But the latest commenter reproduced the issue on macOS. So it will likely be the same on Linux.

[luxmeter]

Regarding the platform: I have the same issue on linux with gradle and webpack.

[thSoft]

I also managed to reproduce this both on macOS and Linux. As a workaround, I kill the started node process (based on the port) besides stopping the Gradle daemon.