[Bug] (bash) autocomplete crashes with ??? in defaults

[goens]

🐛 Bug

Description

When having a configuration that uses ??? in the defaults (to make specifying it mandatory), autocomplete crashes because it looks for that argument first.

Checklist

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

To reproduce

A minimal example, test.py

import hydra

@hydra.main(config_path="conf", config_name="config")
def main(cfg):
    pass

if __name__ == '__main__':
    main()

in conf/config.yaml:

defaults: 
  - test: ???

** Minimal Code/Config snippet to reproduce **

$> eval "$(python test.py -sc install=bash)"
$> export HYDRA_FULL_ERROR=1
$> python test.py t<tab>

** Stack trace/error message **

Traceback (most recent call last):
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/config_loader_impl.py", line 262, in _load_configuration
    run_mode=run_mode,
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/config_loader_impl.py", line 805, in _merge_defaults_into_config
    hydra_cfg = merge_defaults_list_into_config(hydra_cfg, user_list)
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/config_loader_impl.py", line 757, in merge_defaults_list_into_config
    config_group=default1.config_group
hydra._internal.config_loader_impl.UnspecifiedMandatoryDefault

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "test.py", line 9, in <module>
    main()
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/main.py", line 37, in decorated_main
    strict=strict,
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/utils.py", line 372, in _run_hydra
    lambda: hydra.shell_completion(
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/utils.py", line 201, in run_and_report
    raise ex
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/utils.py", line 198, in run_and_report
    return func()
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/utils.py", line 373, in <lambda>
    config_name=config_name, overrides=args.overrides
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/hydra.py", line 247, in shell_completion
    plugin.query(config_name=config_name)
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/core_plugins/bash_completion.py", line 84, in query
    print(" ".join(self._query(config_name=config_name, line=line)))
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/plugins/completion_plugin.py", line 213, in _query
    config_name=config_name, overrides=words, run_mode=run_mode, strict=True
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/config_loader_impl.py", line 156, in load_configuration
    from_shell=from_shell,
  File "/home/goens/.virtualenvs/pykpn/lib/python3.6/site-packages/hydra/_internal/config_loader_impl.py", line 272, in _load_configuration
    raise ConfigCompositionException(msg) from e
hydra.errors.ConfigCompositionException: You must specify 'test', e.g, test=<OPTION>
Available options:

st.py

Expected Behavior

Hydra would ignore the ??? when called with -sc and give me possible autocompletions instead of crashing.

System information

• Hydra Version : 1.0.6
• Python version : 3.6.10
• Virtual environment type and version : virtualenv 20.3.0+ds
• Operating system : Debian experimental (sid)

Additional context

I'd imagine this would also happen with the fish shell, as it seems to be the order in which hydra resolves the -sc argument, which I suppose is shell-independent, but I did not test it.

[omry]

Thanks for reporting. we will take a look at this for Hydra 1.1.