Improve GITHUB_DOMAIN/GITHUB_SERVER_URL default value handling

[Shegox]

Follow up to #4362
Inspired by #2031

Proposed Changes

1. If GITHUB_DOMAIN exists, use its value as GitHub domain
2. If GITHUB_DOMAIN does not exist, but GITHUB_SERVER_URL is already set, use its value as GitHub domain
3. If neither GITHUB_DOMAIN nor GITHUB_SERVER_URL is set, use https://github.com as GitHub domain

Readiness Checklist

You can test the change with following configuration:

• Update the docker image in the action.yml to ghcr.io/shegox/super-linter:github-domains-2 in your testing fork
• Use it with [your-fork]/github-super-linter@[your-branch]

Testing with following settings in GitHub Actions:

1. GITHUB_DOMAIN=https://github.enterprise.com ✅
2. GITHUB_DOMAIN=github.enterprise.com ✅
3. GITHUB_DOMAIN unset ✅

Author/Contributor

• If documentation is needed for this change, has that been included in this pull request

Reviewing Maintainer

• Label as breaking if this is a large fundamental change
• Label as either automation, bug, documentation, enhancement, infrastructure, or performance

//cc @zkoppert

[zkoppert]

I don't think this is going to work with existing configurations. If I understand correctly, existing configurations $GITHUB_DOMAIN looks like mycompany.github.com so that then down on line 677, the https:// is added in.

Your pull request assumes that the user is inputting the https:// and if they don't it chomps up some of the url. ie. echo "zack.github.com/" | cut -d '/' -f 3 returns nothing because the cut has chopped off the who string.

Instead, this code should either detect if the https:// is present in the variable or as previous code did, it should assume it is not present. Does that make sense?

[Shegox]

thats correct, but this is the current behavior as well as I copied the logic from originally line 657 to the top of the script. This code works with both URLs starting with https:// (e.g. https://zack.github.com) as well as ones without any / (e.g. zack.github.com):

Only if you add a trailing slash it starts breaking.

[zkoppert]

Thanks for clarifying. Looking at the code before and after again I think i missed that the first time.