devcontainer: bump ruby version from 2-bullseye to 3-bullseye

[jchilders]

Bump Ruby version for the devcontainer from 2-bullseye to 3-bullseye.

To test:

> devcontainer build --workspace-folder .
# ... no errors ...
> devcontainer up --workspace-folder .
> devcontainer exec --workspace-folder . -- ruby --version
ruby 3.3.5 (2024-09-03 revision ef084cc8f4) [aarch64-linux]

Tests can then be run using:

devcontainer exec --workspace-folder . -- bundle install
devcontainer exec --workspace-folder . -- rake

[jeremy]

Looks like we're already specifying 3-bullseye in devcontainer.json.

Updating the default args in the Dockerfiles is fine, but is this actually a bump?

[jchilders]

I believe so, yes. When I build from main I get the following:

> devcontainer exec --workspace-folder . -- ruby --version
ruby 3.2.2 (2023-03-30 revision e51014f9c0) [aarch64-linux]

Whereas building from this branch gives:

devcontainer exec --workspace-folder . -- ruby --version
ruby 3.3.5 (2024-09-03 revision ef084cc8f4) [aarch64-linux]

This also fixes a bug in the Dockerfile where there is a zero incorrectly prepended to ${VARIANT}.

[jeremy]

Looks like you had the previous 3-bullseye image and changing config resulted in pulling a current version.

[jeremy]

The leading 0- prefix is part of Microsoft's versioning scheme, btw: https://github.com/devcontainers/images/tree/main/src/ruby#using-this-image

[jchilders]

Looks like you had the previous 3-bullseye image and changing config resulted in pulling a current version.

No, I purged Docker before testing this change. I used this:

docker stop $(docker ps -aq) ; docker rm $(docker ps -aq) ; docker rmi $(docker images -q) -f ; docker volume rm $(docker volume ls -q) ; docker network rm $(docker network ls -q) ; docker builder prune -af ; docker system prune -af --volumes

The leading 0- prefix is part of Microsoft's versioning scheme, btw:

Are you sure? I don't see that in the linked document.

[jeremy]

Ah, due to dropping the 0- prefix, then.

The prefix is for versioning the container itself, separate from the Ruby version:

Take a look at other languages' containers and you'll see the same versioning scheme (and tags on the container repo). Tags for Ruby, for example.

[jchilders]

@jeremy Is there a change you are requesting, or is this just an observation?