Re: Bug: Cannot kill Nodejs process using ctrl + c

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Jun 28, 2017, 14:40 UTC
Message-ID: <alpine.DEB.2.21.1.1706281527120.84669@virtualbox>
In-Reply-To: <CAHaNChecHzZqzafe4P85Kz4BtJuisO+krCvm=yPW9wGMXWJK_A@mail.gmail.com>

Hi,

On Mon, 26 Jun 2017, Gyandeep Singh wrote:

> 3. hit "CTRL + c" (2 times) to kill the process.
> 4. If you look at taskmanager, then you will see a node.js process
> still running. or if you try to restart the server it will say port
> 300 already in use.

The way Ctrl+C is handled in Git for Windows changed recently, indeed.

Remember: sending signals to processes to ask them to terminate is *POSIX*
semantics. Not Windows semantics.

On Windows you can terminate a process via the Win32 API. And I really mean "terminate". There is no chance for that process to, say, remove a now-stale .git/index.lock.

We have to jump through hoops to accomodate Git's lack of non-POSIX understandings. In this particular case, we inject a remote thread into the process, running ExitProcess() so that the atexit() handlers have a chance to perform the cleanup that Git so cleverly expects to be able to do when being terminated.

It is probably that thread that is still trying to run when you hit Ctrl+C the second time, and that second time it terminates *just* the shadow process: node.exe is a Console program, and since you run it in Git Bash (which does not have a Win32 Console, but emulates a Unix terminal instead) the node shell alias runs node.exe through a helper called winpty.exe that I suspect gets terminated without taking down its child processes.

Ciao, Johannes