onDidEndTaskProcess's callback is not always fired when a task exits quickly

[g-arjones]

• VSCode Version: 1.27.2
• OS Version: Ubuntu 16.04

Steps to Reproduce:

1. Register a callback using vscode.tasks.onDidEndTaskProcess
2. Execute a process (/bin/false) that returns a non zero code using vscode.tasks.executeTask API
3. Check event.exitCode passed to the callback (should be non zero)

Does this issue occur when all extensions are disabled?: Yes

[g-arjones]

@jrieken @dbaeumer @bpasero Would anyone confirm this, please?

[dbaeumer]

This works for me under Windows using the following shell execution exit 1.

task

{
	// See https://go.microsoft.com/fwlink/?LinkId=733558
	// for the documentation about the tasks.json format
	"version": "2.0.0",
	"tasks": [
		{
			"label": "exit",
			"type": "shell",
			"command": "exit 1",
			"problemMatcher": []
		}
	]
}

code:

    vscode.tasks.onDidEndTaskProcess((event) => {
        console.log(`Exit code ${event.exitCode}`);
    });

Output

Exit code 1

[g-arjones]

Could you try with a task provided by an extension? Also, I had the issue with a ProcessExecution, not sure if it works with a ShellExecution.... Will have a look

[dbaeumer]

Same if I contribute the task via a provider.

[dbaeumer]

I can reproduce under Linux. The reason is that the underlying terminal never signals a terminal.processReady and to not send an unbalance begin/end pair a end process is not signaled either.

@Tyriar any insights why this never fires. Is there a different way for me to know when the process actually started.

[Tyriar]

@alexr00 recently touched this area, a37adb6#diff-dc09948028c646a458fac5f5b5d32276 prevents the process ID promise from firing, but only when the terminal exits immediately.

[g-arjones]

but only when the terminal exits immediately.

Interesting, it seems that that is a different bug though (and that my bug report is not as accurate as it should have been).

The problem I was having was that killed processes are reported with exitCode == 0, which is obviously wrong. What I suggested as step to reproduce actually hits the other bug you mention (the callback is not fired at all).

Please, let me know if you guys would like me to open another issue for that...

[alexr00]

@g-arjones , can you share a task definition that you're seeing this with?

[g-arjones]

@alexr00 You could use this...

1. If you run the "Quick task" that is provided by that test extension you will notice that onDidEndTaskProcess callback is not fired at all (which is the bug @Tyriar mentions..)

2. If you run the "Slow task" and send a SIGTERM or SIGKILL to the task's process, you will notice that the callback is called with exitCode === 0, which is not expected (my original bug report).

Let me know if you need further details..

[sergei-dyshel]

I'm also experiencing that. Had to prepend sleep 0.3 to my shell command (which fails immediately) for the event to be fired.

[g-arjones]

@alexr00 Did you get the time to have a look into this? Thank you!

[alexr00]

@g-arjones, I haven't been able to reproduce this with Windows. I'm trying with Linux next.

[alexr00]

@g-arjones, ok I can reproduce with Linux and I'm looking into it.

[g-arjones]

@alexr00 thanks a lot!

[alexr00]

The task exit code being 0 on Linux has been occurring since at least the beginning of September(went back and checked) so that isn't related to the change I made. This appears to be an upstream issue since 0 is the exit code that we're getting from node-pty.

[g-arjones]

@alexr00 How about the event not being fired if the process ends too quickly?

[alexr00]

It's a different issue, but it also wasn't introduced recently. I'll keep investigating.

[alexr00]

@g-arjones, as you can see I'm working on a change for the exit event not being fired.
For the exit code being 0, I did a bit of research and it looks like the exit code is correctly 0, it's the exit signal that should be set. However, we don't currently expose the exit signal through vscode.tasks.onDidEndTaskProcess. If you want the exit signal (not available on Windows) then feel free to open a separate issue as a feature request 😄

[g-arjones]

as you can see I'm working on a change for the exit event not being fired

Yes, I can see that. Thank you very much for the effort. 😄

I did a bit of research and it looks like the exit code is correctly 0, it's the exit

Strictly speaking, on POSIX systems, if the process is killed there is no exit code (or, to be precise, the exit code portion of the exit status is unset). But the point is: returning 0 as exit code for processes that did not really exit is misleading for extension authors (and would be considered a bug by some, specially given that zero indicates sucess in this context). What shells typically do is return something greater than 127 to indicate that a process was signaled. So, couldn't you do something like that (setting exit code to an arbitrary high number) here? node-pty provides the information you need for that.. On Windows that is a non-issue because the code is never 0 for terminated processes anyway...

/cc @dbaeumer @Tyriar @alexr00

[dbaeumer]

We could also use null to indicate that the process actually didn't provide an exit code.

[g-arjones]

Sounds good...

[alexr00]

@Tyriar, what is your preference on how we handle exit codes?

[alexr00]

New issue for the zero exit code: #62043.