Ruby 3.0 support added, 2.6 removed

[jrafanie]

Hello!

As of yesterday, we merged support for ruby 3.0 on ManageIQ and the various libraries, providers and engines that utilize ManageIQ. Along with adding ruby 3.0 support, we have dropped ruby 2.6 which had reached end of life with the ruby team back in March.

For more information on 3.0, please see the official release notes.

You can stop here if you're not a ruby and rails developer...

For developers, of highest importance for compatibility was the change that separated positional arguments from keyword arguments.

Basically, keyword arguments are no longer treated as a hash argument as the last argument passed to a method. Additionally, you cannot provide a Hash when a method expects keyword arguments. The count of positional arguments or arity is now different as keyword arguments are treated completely differently. With this comes the great possibility of ArgumentError exceptions with ruby 2.x code that's run in ruby 3.0.

Often times, this occurs when a method accepts keyword arguments but is provided a Hash, or conversely, if the method accepts a positional options Hash but are provided keyword arguments. In most situations, you can fix this by making Hash arguments explicit such as changing the method call from foo(:x => 1) to foo({:x => 1}) or vice versa. Additionally methods can leverage **kargs in method definitions to expand keyword arguments to a Hash. Combined with *args in the method definition, you can attempt to handle method calls written with ruby 2.x or 3.x in mind.

Be careful though, as maintaining ruby 2.x and 3.x compatibility is not easy. For more information, I suggest looking at a blog post from a ruby committer Benoit Daloze because many of the different wrong ways to handle this are addressed.