feat: install script for logging on installation

[jthegedus]

Summary

Use an install script to perform the git clone installation process. This allows us to log on installation which is required for the Homebrew installation as outlined in #738 (Homebrew users expect brew install asdf to perform the complete setup of asdf and subsequently report a GitHub issue before going to the docs site to see further instructions)

Fixes: #738

Other Information

• update tag regex (probably can be improved as I'm no sed expert)
• we no longer have instructions in README so deprecate that tag update
• change instructions to curl/wget the install script from the GitHub remote
• use --git-dir and --work-tree to avoid filesystem traversal as git provides this functionality

Notes

• the git checkout uses --quiet flag to supress "detached head" warning on tag checkout. Perhaps we let it log this?
• potentially could reuse ASDF_DATA_DIR instead of introducing another env var

---

Testing output:

with --quiet:

asdf on  feat/install-script [!] 
➜ ./install.bash        
Cloning into '/home/jthegedus/projects/test'...
remote: Enumerating objects: 31, done.
remote: Counting objects: 100% (31/31), done.
remote: Compressing objects: 100% (26/26), done.
remote: Total 5350 (delta 12), reused 13 (delta 5), pack-reused 5319
Receiving objects: 100% (5350/5350), 1007.11 KiB | 808.00 KiB/s, done.
Resolving deltas: 100% (3010/3010), done.

asdf setup
1: install asdf                 completed!
2: add asdf to your shell       https://asdf-vm.com/#/core-manage-asdf-vm
3: add a plugin                 https://asdf-vm.com/#/core-manage-plugins
4: install a tool version       https://asdf-vm.com/#/core-manage-versions

without --quiet:

asdf on  feat/install-script [!] 
➜ ./install.bash        
Cloning into '/home/jthegedus/projects/test'...
remote: Enumerating objects: 31, done.
remote: Counting objects: 100% (31/31), done.
remote: Compressing objects: 100% (26/26), done.
remote: Total 5350 (delta 12), reused 13 (delta 5), pack-reused 5319
Receiving objects: 100% (5350/5350), 1007.11 KiB | 808.00 KiB/s, done.
Resolving deltas: 100% (3010/3010), done.
Note: switching to 'v0.7.8'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at 4a3e3d6 Update version to 0.7.8

asdf setup
1: install asdf                 completed!
2: add asdf to your shell       https://asdf-vm.com/#/core-manage-asdf-vm
3: add a plugin                 https://asdf-vm.com/#/core-manage-plugins
4: install a tool version       https://asdf-vm.com/#/core-manage-versions

[Stratus3D]

I don't think we should adopt this pattern. I know it's popular but it has some risks and I don't think we should push our users in this direction.

See:

• https://sysdig.com/blog/friends-dont-let-friends-curl-bash/
• https://www.seancassidy.me/dont-pipe-to-your-shell.html
• https://news.ycombinator.com/item?id=12766049

[jthegedus]

I agree with all of this. Given it is the install method of choice for Homebrew & OMZSH users I didn't think it was too much an ask, especially since others can still just git clone. Additionally, my understanding of prior discussion of package manager code in this repo was that we didn't want to maintain those either.

But, we don't necessarily need to use this method for people who are using the docs site - see #739 (comment)

[Stratus3D]

I'm not sure that providing links provides much benefit to the user. Why can't we just tell the user what do to add asdf to their shell? If this script is invoked by the package manager we should be able to tell the user exactly what do to for their specific OS/package manager combination.

[jthegedus]

Why can't we just tell the user what do to add asdf to their shell

I think that solution is unmaintainable for us. The number of permutations is making the docs difficult to update as is. nvm does this and their script is 100s of lines of conditional shell scripting which it almost certainly doesn't work in all cases. I'd rather maintain the docs and get users to them instead of automatically editing peoples shell configs.

[jthegedus]

I'm not sure that providing links provides much benefit to the user

The idea was to capture users who hear about asdf and just run their package manager of choices installation, eg brew install asdf, and haven't ever come to the documentation site. These users have find that it doesn't work, they were given no further instructions, and instead of looking for a documentation site to see if there is something they missed, they check GitHub for issues where people used the same package manager and report they themselves are having issues.

I would like to show these people 2 things:

1. there's more steps before you can use asdf
2. these steps are on our documentation site

[jthegedus]

Given we don't need to inform users who are installing from the documentation site about the existence of the site, we could leave the docs as is, and only use the install script in Homebrew and co after they clone the repo as they currently do.

[jthegedus]

I will create an Issue in the repo to pin for Homebrew users to direct them to the documentation. As most Google the issue and end up finding old Issues and resolving the problem via an old method.

Edit: added with #785