[Bug] Child defaults list with interpolation fails with a constructed path with too many group names

[shfattig]

🐛 Bug

Description

A defaults list one level down that points to another defaults list with interpolation is prepending the path with group name too many times.

Checklist

• I checked on the latest version of Hydra
• I created a minimal repro (See this for tips).

To reproduce

files:

configs/
  default_config.yaml
  experiment/
    default.yaml
    exp1.yaml
    parameter1.yaml
  setting/
    parameter1.yaml

default_config.yaml

defaults:
  - group: specific
  - setting: parameter1

experiment/exp1.yaml

defaults:
  - default

experiment/default.yaml

defaults:
  - ${setting}

This setup attempts to provide some default configuration for an experiment given some setting. You can imagine if setting=parameter1, the experiment should include some specific config items. And if you're running the same experiment with setting=parameter2, a different set of config values should be used.

** Stack trace/error message **
hydra.errors.MissingConfigException: In 'experiment/default': Could not load 'experiment/experiment/parameter1'.

Expected Behavior

I expect ${setting} to resolve to experiment/parameter1, but there are instead two "experiment" folders prepended to the path

System information

• Hydra Version : 1.3.0
• Python version : 3.9
• Virtual environment type and version :
• Operating system : Linux

Additional context

Did some digging, it looks like the path for the node is getting prepended at interpolation resolution and then again prepended when calling get_config_path() before attempting to load the config

[AaronYoung5]

Btw not a fix for the bug (not sure if it's a bug or actually intended), but a workaround is by doing the following in experiment/default.yaml:

defaults:
  - /${setting}