Incompatibilities when upgrading asdf

[purinkle]

When running the script on a machine with an upgraded asdf version (0.15 -> 0.16), the script fails with the following.

Installing latest Ruby ...
Updating rubygems-update
ERROR:  While executing gem ... (Gem::FilePermissionError)
    You don't have write permissions for the /Library/Ruby/Gems/2.6.0 directory.
failed

The script also outputs asdf's "help" text several times.

The linked branch resolves this issue on my machine but outputs the following on a fresh macOS build.

No plugins installed

Installing latest Ruby ...
No compatible versions installed (ruby )
No versions specified for ruby in config files or environment
failed

I expect the script to be idempotent.

The current main version works on a fresh macOS build.

[cpytel]

Thanks for creating this issue.

The linked branch resolves this issue

What branch?

[cpytel]

Looking into the issue to triage it, it appears that when gem update --system is being called, which is run after installing the latest ruby in asdf, the default macOS gem is being run, rather than the version from asdf.

We may need to do something there to ensure that the ruby asdf is used there.

[cpytel]

Oh, I just spotted a branch linked in the sidebar of this issue. I wasn't aware that was a thing.

[purinkle]

Let me know if you want to pair on this issue. I started hacking around a solution. It would be helpful to work with a second set of eyes.

[smaboshe]

A number of breaking changes were introduced in asdf 0.16.0:
https://asdf-vm.com/guide/upgrading-to-v0-16

Linking to their guide for context.

[cpytel]

I've spent some time looking into this because I needed to fix it on my own computer and I'm skeptical that it is worth the effort to make the script run reliably on both versions, and then maintain that, but the fix is tricky.

I'm wondering if a better approach will be for the script to check if asdf is installed already, and upgrade asdf and set the path appropriately if it's not already running 0.16. But even that is tricky.