[Bug] Hydra's override grammar allows quoted resolver args, but OmegaConf does not recognize them

[odelalleau]

🐛 Bug

Description

Best explained with an example (assume a basic my_app.py that prints the resolved config):

python my_app.py +port='${env:PORT}'     # works, may crash if PORT is not defined
python my_app.py +port='${env:PORT,80}'  # crashes: not recognized by Hydra's grammar
python my_app.py +port='${env:PORT,"80"}'  # accepted by Hydra but OmegaConf does not resolve it

This is because in the current version of OmegaConf, quotes are not allowed inside interpolations.

Checklist

• I checked on the latest version of Hydra
• I created a minimal repro

To reproduce

** Minimal Code/Config snippet to reproduce **

from omegaconf import DictConfig, OmegaConf
import hydra

@hydra.main()
def my_app(cfg: DictConfig) -> None:
    print(OmegaConf.to_yaml(cfg, resolve=True))

if __name__ == "__main__":
    my_app()

Then try the examples above.

** Stack trace/error message **

Just showing the last example:

port: ${env:PORT,"80"}

Expected Behavior

Hydra should allow the same characters as OmegaConf.

System information

• Hydra Version : current master (7afee09)
• Python version : 3.8.3
• Virtual environment type and version : conda 4.8.3
• Operating system : MacOS