gem install mrml fails with Ruby 3.4.0.preview1

[spickermann]

I know that Ruby 3.4.0.preview1 was released just one day ago. And that it is a very first preview version and far from the final release. But I thought you might be interested in keeping an eye on it, nevertheless.

Please tell me when you need additional information or when I can support you in any way.

Describe the bug

Installing the mrml gem fails to install on Ruby 3.4.0preview1 (installed with rbenv on a Mac M1) with a long stacktrace (see link to gist below).

To Reproduce

# Preparation: Install Ruby 3.4.0preview1 (for example with rbenv)
$ brew update rbenv ruby-build
$ rbenv install 3.4.0-preview1
$ rbenv shell 3.4.0-preview1
$ ruby -v
ruby 3.4.0preview1 (2024-05-16 master 9d69619623) [arm64-darwin23]

# Try installing mrml
$ gem install mrml
[long stacktrace, see link to gist below]

Expected behavior

MRML is installed without error message

Additional context

Please find both – the error message from the CLI, including the stacktrace, and the log file generated by gem install – in this gist: https://gist.github.com/spickermann/e5f6794cb688bccfb9e66d0eeea61328

[ingemar]

We need a pre-release of mrml for Ruby 3.4.0-preview2:

3.4 is not a stable release, and the ruby API is unstable so native gem compilation will not be guaranteed to work in future versions. what you want is to package a source code gem with the stable-abi-compiled-fallback feature to support ruby head
~ ianks in oxidize-rb/rb-sys