Hydra 1.1 when composing a config that is a list at the top level.

[omry]

Hydra 1.1 raises an error when composing a config if a used config is a ListConfig.

1. Determine behavior in Hydra 1.0
2. If behavior makes sense, allow maintain compatibility, otherwise issue an appropriate error.
   Current error:

        if not isinstance(ret.config, DictConfig):
            raise ValueError(
                f"Config {config_path} must be a Dictionary, got {type(ret).__name__}"
            )

(Note that the error is reporting the wrong type, should be type(ret.config)).

The following should reproduce the issue:

group/file.yaml:

- a

config.yaml

defaults:
 - group: file