[Bug]: Shared variables not substituted in Docker Compose projects

[colinmollenhour]

Description

According to the docs I should be able to use shared variables like {{team.VAR}}. However, if I use these in a docker-compose.yaml file like below, they are not substituted:

services:
  mariadb:
    image: mariadb
    environment:
      - MYSQL_USER_PASSWORD={{team.MYSQL_PASSWORD}}

Discussion started here with no response: https://discord.com/channels/459365938081431553/1228241023487184907/1228241023487184907

Maybe I'm misunderstanding where these substitutions can occur? It is not clear at all from the docs.

Minimal Reproduction (if possible, example repository)

Create a Team variable called SENDGRID_API_KEY, reference it in a docker-compose.yaml file and create a resource using the Docker Compose file. Inspect the docker container to see if the environment was set correctly.

services:
  web:
    image: nginxdemos/hello
    volumes: 'web:/app'
    environment:
      - MYVAR=Testing...
      - SG_API_KEY='{{team.SENDGRID_API_KEY}}'
      - SG_API_KEY2={{team.SENDGRID_API_KEY}}

The docker inspect command shows this:

            "Env": [
                "SG_API_KEY2={{team.SENDGRID_API_KEY}}",
                "MYVAR=Testing...",
                "SG_API_KEY='{{team.SENDGRID_API_KEY}}'",
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "NGINX_VERSION=1.25.5",
                "PKG_RELEASE=1",
                "NJS_VERSION=0.8.4",
                "NJS_RELEASE=3"
            ],

Exception or Error

No response

Version

v4.0.0-beta.276