Dev Containers (version 0.275.x) corrupts existing X forwarding in docker container

[johan-laneau]

• VSCode Version: January 2023
• Local OS Version: Windows 10 22H2
• Remote OS Version: Ubuntu 20.04
• Remote Extension/Connection Type: Containers

Steps to Reproduce:

1. Create a docker container with a socket mounted to forward X communication from e.g. WSL to the docker container. I do this via docker-compose.yml file with following lines
   '''volumes:
   • source: /tmp/.X11-unix
     target: /tmp/.X11-unix
     type: bind
     '''
2. Then create devcontainer.json for the docker-compose.yml and launch VS Code January 2023 edition.
3. The X forwarding in the docker container does not work anymore.

The issue started occurring since Dev Containers (version 0.275.x) that was installed together with VS Code January 2023 version. I assume it is caused by the X11 & Wayland Forwarding that was introduced in this version.
I think the extension should detect that the docker container already has X forwarding and then not try to insert its own forwarding.

My current work-around is the locally remove the X forwarding from the docker-compose.yml file. Then, the docker container will use the docker forwarding inserted by the dev container extension. However, this workaround is not good because I can't use the same docker-compose.yml file for other usecases where VS Code is not used and X forwarding is still required.

[ahayzen]

Note i've started a feature request to prevent all automatic forwarding of sockets #8031 so that this doesn't silently fail again and allow for opting out of forwarding.

I also think that if forwarding is enabled it should not set the env var if it is already set in a container that is being attached to (or at least warn that it is overwriting).

[chrmarti]

Tracking as #7983.