environment.yml works, environment.yaml doesn't

Bug description

Hey 👋 Not sure if this is a bug or an intentional feature so opened an issue for discussion.

When building an image using conda, repo2docker accepts environment.yml files but does not pick up environment.yaml files. Is there a reason for this that I’m missing?

Expected behaviour

Both the .yml and .yaml file extensions would be valid and repo2docker would successfully build both envs with conda.

Actual behaviour

Only the .yml file is recognised. Building with .yaml succeeds but none of the requested packages are installed.

How to reproduce

I created two repos to test this on mybinder.org.

.yml extension: Repo: https://github.com/sgibson91/test_repo_yml Binder link: https://mybinder.org/v2/gh/sgibson91/test_repo_yml/main

.yaml extension: Repo: https://github.com/sgibson91/test_repo_yaml Binder link: https://mybinder.org/v2/gh/sgibson91/test_repo_yaml/main

Both repos contain environment files that should install numpy, pandas and matplotlib. By clicking the binder links, opening a new notebooks and attempting to import any (or all) of these packages is successful in the .yml repo and fails in the .yaml repo.

Your personal set up

Currently testing on mybinder.org

[betatim]

I wouldn’t prioritise it because I don’t think it is a common problem 😕

[betatim]

I would not add support for this. I think environment.yaml is pretty rare and it seems people have “agreed” that environment.yml is the name everyone should use. It is also the one mentioned in documentation like https://docs.conda.io/projects/conda/en/latest/user-guide/tasks/manage-environments.html#creating-an-environment-from-an-environment-yml-file