Description

It would be great if two compose files like this:

services:
  nginx1:
    image: nginx:latest

x-test:
  test: 123

services:
  nginx2:
    image: nginx:latest

x-test:
  abc: 123

would result in a merged x-test extension when used via docker compose config -f file1.yaml -f file2.yaml. Currently the result is:

services:
  nginx2:
    image: nginx:latest

x-test:
  abc: 123

and I'd love to see:

services:
  nginx2:
    image: nginx:latest

x-test:
  test: 123 # This is different
  abc: 123

Is the current behavior on purpose or would you be open to a MR to "fix" the current behavior?