Quote your ports in Docker compose file

I struggled for quite a while to fix a Docker compose problem. I have this simple config line:

services:
  git:
    ports:
      - 2222:22

But I kept getting an error message when trying to start the instance:

  Cannot create container for service git: invalid port specification: "133342"

What the heck, where did that weird number come from ?!
It turns out YAML 1.1 supports so called "base 60 float" useful for time calculation. So 2222:22 is interpreted as 2222*60+22 which is 133342. ta-dah! It is not a problem if the parts contain numbers bigger than 60, e.g. 3306:3306, or 8080:80, so this problem does not always occur, making it covert.
So quote your ports!

services:
  git:
    ports:
      - "2222:22"