Omnisharp does not terminate it's existing process when it is restarted.

[bakakaba]

Environment data

dotnet --info output:
.NET Command Line Tools (1.0.1)

Product Information:
Version: 1.0.1
Commit SHA-1 hash: 005db40cd1

Runtime Environment:
OS Name: fedora
OS Version: 25
OS Platform: Linux
RID: fedora.24-x64
Base Path: /opt/dotnet/sdk/1.0.1

VS Code version: 1.11.2
C# Extension version: 1.9.0

Steps to reproduce

1. Open a C# project and let omnisharp do its thing.
2. Select restart omnisharp from the command palette.

Expected behavior

The old omnisharp process is terminated and a new one is created.

Actual behavior

The old omnisharp process remains and a new one is created.
This causes multiple omnisharp process for the same window and chews up memory.

[bakakaba]

From @DustinCampbell the related lines that should stop the process is https://github.com/OmniSharp/omnisharp-vscode/blob/cc79712200e9530a77da050f52f58920c5882d41/src/omnisharp/server.ts#L339-L343

[bakakaba]

Looks like the issue for this is that the Omnisharp process is a child process in a bash shell of which vscode has the reference to as the server process.

code
    code (extension host)
        bash <- vscode has this as the extension process and this is sent the SIGTERM when omnisharp is reloaded
            mono (omnisharp)

The omnisharp process becomes orphaned but doesn't get cleaned up until vscode exits (https://nodejs.org/api/child_process.html#child_process_child_kill_signal).

My proposal is to use https://www.npmjs.com/package/ps-tree and fire the kill signal to the children instead when terminating.

[DustinCampbell]

Thanks for the additional investigation! I see the problem now. About six months we changed our launcher on Unix to a shell script that launches OmniSharp on Mono. When we did that, we failed to update the code that terminates the process to handle the fact that Mono is now a child process of our shell script.