Confusing error message when overriding hydra/launcher from a nested defaults list without absolute and global package

🐛 Bug

Description

I have a config file which, among other things, is supposed to turn on the “submitit_slurm” launcher. This is not the “main” config for the python file, it’s another config which I add in using the command line. When I add this config, I get the following error:

/private/home/mehrlich/.conda/envs/qgac/lib/python3.7/site-packages/hydra/_internal/defaults_list.py:394: UserWarning: In cluster/slurm_fair: Invalid overriding of hydra/launcher:
Default list overrides requires 'override' keyword.
See https://hydra.cc/docs/next/upgrades/1.0_to_1.1/defaults_list_override for more information.

  warnings.warn(msg, UserWarning)
In 'cluster/slurm_fair': Could not override 'hydra/launcher'. No match in the defaults list.

Set the environment variable HYDRA_FULL_ERROR=1 for a complete stack trace.

but I’m not trying to override hydra/launcher I’m trying to add it so I think it should work and changing the config to override hydra/launcher: submitit_slurm throws the same error. See minimal repro.

Checklist

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

To reproduce

code

minimal.py:

import hydra
from omegaconf import DictConfig


@hydra.main(config_name="minimal", config_path="configs")
def main(cfg: DictConfig):
    return


if __name__ == "__main__":
    main()

configs, place in a folder named configs

minimal.yaml:

defaults:
  - hydra/launcher: submitit_slurm

Note: This file can be empty and it won’t change the behavior at all

slurm.yaml, place in configs/launcher

defaults:
  - hydra/launcher: submitit_slurm

run

python minimal.py this will work fine python minimal.py +launcher=slurm this will crash with the stated error. Again this happens regardless of the contents of minimal.yaml and adding override in slurm.yaml also doesn’t help.

Stack trace/error message

/private/home/mehrlich/.conda/envs/qgac/lib/python3.7/site-packages/hydra/_internal/defaults_list.py:394: UserWarning: In cluster/slurm_fair: Invalid overriding of hydra/launcher:
Default list overrides requires 'override' keyword.
See https://hydra.cc/docs/next/upgrades/1.0_to_1.1/defaults_list_override for more information.

  warnings.warn(msg, UserWarning)
In 'cluster/slurm_fair': Could not override 'hydra/launcher'. No match in the defaults list.

Set the environment variable HYDRA_FULL_ERROR=1 for a complete stack trace.

Expected Behavior

No error.

System information

• Hydra Version : 1.1.0.dev3
• Python version : 3.7.7
• Virtual environment type and version :
• Operating system :

Additional context

Add any other context about the problem here.

[Queuecumber]

Yeah thats perfect, I didn’t know you could do an absolute path like that, I actually need to go over the 1.1 docs in more details because I know a lot of stuff changed

[omry]

Add a global package header to your your launcher/slurm.yaml and use absolute addressing:

# @package _global_
defaults:
  - override /hydra/launcher: submitit_slurm

This is documented in configuring experiments. The error is definitely confusing and I will take a look see how it can be improved.