Hydra: Zsh completion support

[moskomule]

🚀 Feature Request

Zsh completion support as well as bash.

Motivation

I tried hydra's bash completion and I was amazing. However, I usually use zsh, so I want Zsh completion. I found related PRs such as https://github.com/facebookresearch/hydra/pull/263, but there is no progress so far.

Pitch

As far as I tried and googled, zsh requires a completion function to be saved as a file somewhere and loaded again. I think it makes installation a bit difficult compared to bash's eval $(python file.py -sc install=bash). I want to know better solutions if you know.

[omry]

Hi @moskomule.
This is low priority but I am happy to help whoever wants to implement it.

When I implemented the bash support I did have other shells in mind, so it wouldn't be implementing from scratch.

However, implementing it will probably take a few days to whoever wants to try. I am happy to offer advice to anyone giving it a shot.

[ravindranrahul]

Hi @omry, Is this still relevant?

Im willing to give this a shot.

[omry]

Yup, still relevant.

[selflein]

Just leaving a comment here since there is no updates on this and it was a major pain point for me before switching over to hydra completely.

One can use bash completions with zsh (Source). So the idea is to just use the existing bash completion which is already in place.

However, the current completions script uses the options as a variable which is a keyword in zsh. So there a minor changes necessary in the bash completion script found in hydra/_internal/core_plugins/bash_completion.py. Basically replace the occurrences of options with e.g. choices and replace the single quotes with double quotes for this line

COMPREPLY=($( compgen -o nospace -o default -W '$options' -- "$word" ));

Replace with

COMPREPLY=($( compgen -o nospace -o default -W "$choices" -- "$word" ));

Afterwards, put this in your .zshrc

autoload bashcompinit
bashcompinit

after compinit and restart your shell.

Then one can just do

eval "$(python path_to_your_hydra_main.py -sc install=bash)"

and it should work!

Hope this helps someone!

@omry, are you willing to upstream these changes if I create a PR? This is also what, e.g., Apache Airflow is recommending for zsh users .

[omry]

I am certainly open to this change, but:

1. it should also include documentation changes.
2. there should be some way to communicate this to zsh users in the --hydra-help (probably with a link to the website that explains it).