The short syntax example for configs says this:

The following example uses the short syntax to grant the redis service access to the my_config and my_other_config configs.

…but it doesn’t list my_other_config in the actual code.

services:
  redis:
    image: redis:latest
    configs:
      - my_config
configs:
  my_config:
    file: ./my_config.txt
  my_other_config:
    external: true

Describe the solution you'd like

Add - my_other_config to services.redis.configs.

PR incoming.