topic: extends, "Circular reference" when trying to extend more than 1 service

[brianclaridge-wf]

This may not be a bug and intentional, but it appears extends has a "Circular reference" problem when extending more than one level:

08:18:49 ~/workspaces$ cat docker-compose.yml && fig run bar bash
base:
    image: ubuntu:latest

foo:
    extends:
        file: docker-compose.yml
        service: base

bar:
    extends:
        file: docker-compose.yml
        service: foo
Circular reference:
  bar in ./docker-compose.yml
  extends bar in /Users/brianclaridge/workspaces/docker-compose.yml
08:18:56 ~/workspaces$

Curiously, fig run foo bash results in the same error. If I remove the bar service -- I can run foo again.

[dnephin]

I think if the service is in the current file, you can't use the name of the file. I don't remember if we left support for extending from the current file or not. Can you try without file: ... ?

[brianclaridge-wf]

No sir, seems to require file:

08:32:32 ~/workspaces$ cat docker-compose.yml && fig run bar bash
base:
    image: ubuntu:latest

foo:
    extends:
        service: base

bar:
    extends:
        service: foo
Traceback (most recent call last):
  File "<string>", line 3, in <module>
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.cli.main", line 31, in main
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.cli.docopt_command", line 21, in sys_dispatch
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.cli.command", line 27, in dispatch
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.cli.docopt_command", line 24, in dispatch
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.cli.command", line 57, in perform_command
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.cli.command", line 76, in get_project
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.config", line 55, in load
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.config", line 65, in from_dictionary
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.config", line 88, in make_service_dict
  File "/compose/build/docker-compose/out00-PYZ.pyz/compose.config", line 100, in resolve_extends
KeyError: 'file'

[dnephin]

Ok, that sounds like a problem

[ghost]

As a workaround, I can put the root service in it's own file:

08:54:31 ~/workspaces$ cat base.yml && cat docker-compose.yml && fig run bar bash
base:
    image: ubuntu:latest
foo:
    extends:
        file: base.yml
        service: base

bar:
    extends:
        file: docker-compose.yml
        service: foo
root@ece77849ab56:/# echo "success!"
success!

[aanand]

Yep, this looks like a bug. We should fully support extending within the file (and we should allow you to omit the file key for that purpose).

[ferdynice]

Omitting the file key should be no-brainer when referencing the current file.

[aanand]

Closed by #1632.