Debug: node.js does not terminate when debugging simple script

[bpasero]

I have a very simple index.js file with a "console.log()" statement and run it via debugger. The debugger does not terminate though, but keeps running. I would expect the debugger to stop after the console.log.

@weinand @isidorn fyi

[isidorn]

This was like this since the beggining of time - I also see it in stable.
Forwarding to @weinand since the debug adapter does not send a terminate signal - it probably does not arrive from node

[joaomoreno]

@isidorn Surely this hasn't been like this forever. If a program is done, it's done, and the debugger used to quit debugging. Now I just think the program is still alive when it isn't.

It's especially bad if you are debugging a node server which crashes. The debugger shows the user that it is still running but you cannot hit it with the web browser...

[isidorn]

@joaomoreno I remember this was like this since at least 6 months, but I think since day 1. This is how node behaves @weinand can correct me here
For debugging other languages once they are done we exit the debugging session because their program terminates and the adapter sends the appropriate signal to vscode

[joaomoreno]

No it's not.

Node stops executing when there is nothing more to execute; it continues executing otherwise (e.g. when a setTimeout or setInterval is still pending, or waiting for IO).

If a script contains

console.log('goodbye')

What you get by running node script.js is goodbye and the process exits.

[weinand]

@joaomoreno what you describe is the 'happy path' (non debug) mode of node.js.

Please run your one line snippet from above in debug mode from the command line:

node --debug-brk test.js 

and then attach node-inspector and run the program to the end. You will find that the node process does not exit.

So @isidorn is right: this has been like this forever.

Your statement from above 'It's especially bad if you are debugging a node server which crashes....' is unfounded because node server crashes are not affected by node running in debug mode.

[joaomoreno]

I have to disagree, that behaviour just appears to be a bug that no one cares. A bit of searching yielded nodejs/node#1788 which they seem to be picking up soon. It's a bug since 0.12; version 0.10 actually behaves as I and Ben expect it to.

Since this is a bug in Node itself I propose to just close this issue.

[millermatt]

Node team has replaced the debugging engine and even though the same behavior is observed they are encouraging more digging into the VSCode side.

nodejs/node#1788 (comment)

Is it possible to re-open this for more research?

@joaomoreno @weinand

---

Actual behavior
debug session does not stop when node script has finished running

Expected behavior
when a node script has finished running, the debug session should end

Steps to reproduce

1. Open an empty folder in VSCode
2. Add a default launch debug configuration (Debug->Add Configurations...)
3. Create a .js file with contents console.log('test');
4. Launch the debugger
5. Observe that the debug toolbar stays active and indicates that the script is executing after 'test' has been written to the console

OS: Ubuntu 17.10 & MacOS Sierra
Node: v8.1.2
Editor: Visual Studio Code 1.13.1

[weinand]

The VS Code node debugger ends the debug session on receipt of a terminate event from the runtime.
If such an event is not received, VS Code cannot end the session.
It is as simple as that.

@roblourens do you receive a terminate event with the inspector protocol?

[roblourens]

This is fixed in 1.14 - microsoft/vscode-node-debug2#11

[weinand]

@roblourens we should mention in the release notes that this long-standing node.js bug has been finally fixed and that this will show up for the inspector protocol.