config does not validate broken subnets

[schmunk42]

docker-compose 1.11.2

Broken config, due to missing variable - no error during config

networks:
  default:
    ipam:
      config:
      - subnet: ''
      driver: default

On docker-compose up

ERROR: Invalid subnet  : invalid CIDR address:

Should be thrown already during validation.

[tilakpatidar]

This can be fixed by adding a regex pattern for the subnet in config_schema.
In pull request, a new version of config_schema should be created or the previous version should be updated? I am a beginner need some help.

[dgageot]

Here's a full compose file to reproduce the issue:

version: '2.1'

services:
  test:
    image: busybox

networks:
  default:
    ipam:
      config:
      - subnet: ''
      driver: default