Explicitly set the environment defaults in settings.py

[merelcht]

Description

I think Remove the environment default for ConfigLoader might have an unexpected side effect. If you set CONFIG_LOADER_ARGS it will override the default set in _ProjectSettings and so it will override base_env and default_run_env. I noticed this because in the starters using spark we have:

CONFIG_LOADER_ARGS = {
#       "base_env": "base",
#       "default_run_env": "local",
    "config_patterns": {
        "spark": ["spark*", "spark*/**"],
    }
}

If I don’t uncomment base/default env, I will get an error saying it can’t find spark config inside myproject/conf: https://app.circleci.com/pipelines/github/kedro-org/kedro-starters/889/workflows/f1376cb4-be57-4429-8a1b-a8b9a3a31150/jobs/10413

Development notes

Option 1:
Make sure the env defaults don't get overwritten when not explictly a…
This is a fix to check inside the session if base_env or default_run_env has been specified and if not it shouldn’t overwrite the default.

Option 2:
7ad31c8
Alternatively, we can just add the default base_env and default_run_env to settings.py. If a user removes that, it's less unexpected that this will change the behaviour IMO. That way we don't need to change the session.

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Checklist

• Read the contributing guidelines
• Signed off each commit with a Developer Certificate of Origin (DCO)
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change in the RELEASE.md file
• Added tests to cover my changes
• Checked if this change will affect Kedro-Viz, and if so, communicated that with the Viz team

[merelcht]

My preference goes to option 2 in the PR description, because IMO it’s more transparent to the user what happens here. No more magic treating of base and local environment.

[DimedS]

Option 2 also seems to me more clear, thanks for PR @merelcht

[astrojuanlu]

Alternatively, we can just add the default base_env and default_run_env to settings.py. If a user removes that, it's less unexpected that this will change the behaviour IMO. That way we don't need to change the session.

+1

[astrojuanlu]

💯 "Explicit is better than implicit"