Regression in support for multiple env_specs in anaconda-project lock

[jlstevens]

While working on https://github.com/pyviz-topics/examples/pull/145 I found that the output of anaconda-project lock has changed since version 0.8.2 given the same anaconda-project.yml.

If you use 0.8.2 the test environment in the env_spec is locked and re-created properly. But in 0.9.0 and 0.9.1 the pytest package no longer appears anywhere in the lock file.

[AlbertDeFusco]

It looks like there is some room for improvement here, but I would say it's not recommended to use both packages and dependencies. I would recommend that you must match the package spec key between global and env-spec. Note that dependencies is preferred as of version 0.9.1 and will ignore packages if both are found.

I have enumerated three working scenarios.

Dependencies-only

name: lock-deps

dependencies:
- python=3.7.6

platforms:
- linux-64
- osx-64
- win-64

env_specs:
  default: {}
  test:
    dependencies:
      - pytest

> anaconda-project lock
> grep pytest anaconda-project-lock.yml
      - pytest=6.2.3=py37h06a4308_2
      - pytest=6.2.3=py37hecd8cb5_2
      - pytest=6.2.3=py37haa95532_2

Packages-only

name: lock-deps

packages:
- python=3.7.6

platforms:
- linux-64
- osx-64
- win-64

env_specs:
  default: {}
  test:
    packages:
      - pytest

> anaconda-project lock
> grep pytest anaconda-project-lock.yml
      - pytest=6.2.3=py37h06a4308_2
      - pytest=6.2.3=py37hecd8cb5_2
      - pytest=6.2.3=py37haa95532_2

Mixed

Here is a backwards compatible anaconda-project.yml file that can also serve as a valid environment.yml file. If dependencies is left off of the env_spec: test key you will get the failure specified.

name: lock-deps

packages: &pkgs
- python=3.7.6

dependencies: *pkgs

platforms:
- linux-64
- osx-64
- win-64

env_specs:
  default: {}
  test:
    packages: &testpkgs
      - pytest
    dependencies: *testpkgs

> anaconda-project lock
> grep pytest anaconda-project-lock.yml
      - pytest=6.2.3=py37h06a4308_2
      - pytest=6.2.3=py37hecd8cb5_2
      - pytest=6.2.3=py37haa95532_2

[jbednar]

Thanks. I don't know why anaconda-project ever used a different name for the package list than conda did, but because of that and because we work with clients who are tied to older anaconda-project versions due to the commercial software involved, we try to support any anaconda-project and conda version where possible. It looks like your last recipe there will let us do that. Ideally a-p would warn if packages and dependencies differ when both are present, to detect a problem like that.

[jlstevens]

I would be in favor of a warning as Jim suggests (when there is a conflict) but otherwise I am happy with Albert's recommendations.