docker-compose container name separator switches between - and _. #24

• I have tried with the latest version of Docker Desktop
• I have tried disabling enabled experimental features
• I have uploaded Diagnostics
• Diagnostics ID: B6CD6541-132F-4401-A847-57D0C1C6D921/20211209193540

Actual behavior

docker-compose switches between - and _ as a container name separator between releases.

Expected behavior

docker-compose must consistently use - as a container name separator.

Information

• Running with Docker Desktop 4.3.0 (71786) on Windows 11, with the WSL2 backend.
• Docker Compose V2 is checked in the settings. docker-compose version is v2.2.1.
• This seems to have appeared with the 4.3.0 update. It is not noticed unless you rebuild your environment. I.e. existing environments continue to use - as the container name separator.
• I had the same issue a couple of months back. That time, it was also fixed with an update.

Steps to reproduce the behavior

• Sample docker-compose file:

  version: '3.4'
  
  services:
    db:
      image: postgres:latest
      restart: always
      ports:
        - "127.0.0.1:1020:5432"
      volumes:
        - postgres:/var/lib/postgresql/data
      env_file:
        - .env
      environment:
        - PGDATA=/var/lib/postgresql/data/pgdata
  volumes:
    postgres:

• Steps:

  docker-compose -f docker-compose-test.yaml -p separator-test up
  # creates separator-test_db_1
  docker-compose -f docker-compose-test.yaml -p separator-test down
  sudo wget -q https://github.com/docker/compose/releases/download/v2.2.1/docker-compose-linux-x86_64 -O /usr/local/bin/docker-compose-v2.2.1-gh
  sudo ln -sf /usr/local/bin/docker-compose-v2.2.1-gh /usr/bin/docker-compose
  docker-compose -f docker-compose-test.yaml -p separator-test up
  # creates separator-test-db-1
  docker-compose -f docker-compose-test.yaml -p separator-test down
  sudo ln -sf /mnt/wsl/docker-desktop/cli-tools/usr/bin/docker-compose /usr/bin/docker-compose /usr/bin/docker-compose