What is reccomended practice for version restrictions in rubygem add_dependency? - ruby

When authoring a gem, what would be reccomended practice for version restrictions of dependencies. For example I know that know that my gem works wih rubyzip version 2.x, but I also know that it works for 1.9 as well. Should I state
spec.add_runtime_dependency 'rubyzip', '>1.8'
or if the rubyzip version 1.9 is long time outdated, it is more common to "push" change for 2.x line? Also if I use the mentioned line, that I risk incompability with future versions, but on the other hand, leave the coice to the user.
Note: the questions is generall and dependency on rubyzip is just an example.

If you know that your gem works with rubyzip 1.9, then there's really no need to force people to use >=2.0 with it.
Sure, updating dependencies would be a good idea for your library-user to do, but it's not your job to be the "update-your-software-police"!
Specifying that the version must be < 3 is generally advisable (although not consistently done by developers), as there's a reasonable risk that a major dependency version bump will be incompatible with this version of your code.
So, as a compromise, you could do:
spec.add_runtime_dependency 'rubyzip', '>=1.9', '<3'
See the documentation for valid syntax examples.

Related

Do old gems always work on later versions of ruby?

I am using a quite recent version of ruby (2.5.1) but some old gems. I am having some issues. I was wondering, is it correct that some gems work only with certain versions of ruby?
If a gem worked with ruby 2.3.0, is it true that it will definitely work with 2.5.1 (i.e. because 2.5.1 > 2.3.0)? Or is that not always the case?
I guess what I'm asking is are newer ruby versions always backwards compatible with older gems?
If a gem worked with ruby 2.3.0, is it true that it will definitely
work with 2.5.1
This is not correct. Programming languages are evolving while growing. This means language maintainers are doing lots of improvements or refactorings that they are new features or removing old components from the language. When the language community announces for new features or removing old feature such as Fixnum in ruby, the developers should follow the instructions and refactor their codebase accordingly. In other words, developers should have a good test coverage to detect any fail and fix it instantly.
In your scenario, as well as I understand you do not have a test coverage. The only but the simple thing should do is just upgrade your gems' versions to latest.
Gem is simply a plug-in library written in Ruby.
Of course, Ruby is developing, new features are appearing, old ones are disappearing.
It's best practice to specify Ruby version in .gemspec file. For example, like this one.
But if not, then you have to manually check the performance. So you can read gem source code or try to use your gem and check it.
For automation, of course, it is best to use tests.
Starting at Ruby 2.1.0 the version policy has been that a change in the MINOR version may introduce API breaking changes.
Should any gem happen to use an API that changes, an incompatibility will arise.
The MINOR version number has changed twice between 2.3.* and 2.5.* so even if a gem happens to have been written in accordance with the documented API, there's no guarantee that it will continue to work unless the gem's maintainer takes the effort to test the gem (and upgrade it if necessary). Automated test suites help a lot.
A standard way to document version compatiblity that is actually tested against is by providing required_ruby_version in .gemspec files.
Interestingly, if a particular gem is really badly written, I imagine it might break even between compatible versions of Ruby. That's not something I've encountered in the Ruby ecosystem but I've made a similar mistake writing Java code (and Java is famous for its backward compatibility) where my own code accidentally used a class that wasn't part of the API. There are many gems. Who knows what's out there? :)

Gem development - should I update dependency if depending gem has bug

Hi I am building a gem which depends on the multi_json gem, which is basically adapters to all other json encoder/decoders out there.
So an user filed an issue on my gem. He has issues because multi_json has a small bug in one of the adapters, which is later fixed on multi_json's end, so it is not really my issue.
I am wondering if I should change my gemspec to hardcode the dependency to the fixed version of multi_json. I thought it would be easier to just tell the user to explicitly specify to use the fixed version of multi_json. This way my dependency won't be too strict and conflict with other gems which use multi_json.
What are the thoughts on this?
You don't have to lock dependency version entirely, just make sure that you have release that have above-mentioned bug fixed. For instance,
gem 'multi_json', '> 1.9.1'
It will be on rubygems sooner or later and you're definitely not interested in encountering the same bug twice.
My opinion is that the reliability of your library in the present is more important than future development inconveniences, which may or may not occur.
As for what to tell your users, they should've already heard (and if they haven't you could remind them of this in the README.md) that most of the critical problems usually are solved within the day and can be found in master. So if they want to take advantage of the latest fixes (and the freshest new bugs), they could specify github as a source:
gem 'your_gem', github: 'lulalala/your_gem'

How can I find what version of ruby an app was written for?

I'm using rvm on Ubuntu 12 to manage ruby versions/gemsets. I am testing various projects and some gems won't work with certain versions of Ruby or with each other. Is it possible to find which version of ruby an app was written for, so I can set my rvm to use that version and get the right gems when I run bundle install?
You can lookup the gems on rubygems.org. They are supposed to list what version of ruby they are compatible with, but that may not always be kept up to date.
If that doesn't narrow it down, you can check the gem's CHANGELOG file on github.
In the end, you may have to just try a few. There's only a handful of versions in common use, so it's not like you have to try then all.
in my experience ruby 1.9.3 is most widely supported at the time of this writing. Ruby 2.0 and 2.1 would also be good to try. 1.8.7 is pretty old and will likely give you a good bit of trouble, but it was the standard for a long time.

Supporting newer gems on old ruby (here: Celluloid)

Is it possible, by using backports or something similar, to install and use gems that require a higher version of ruby than what is installed?
I am stuck on 1.8 and I am having troubles with the celluloid gem in relation with rspec. I thought that maybe backports would enable me to use it since most/all ruby 1.9.2+ features are then made available.
Forking celluloid on github and using backports to bring it down to 1.8 would be one possibility.
Although not a very simple one! :-)

Should a useful gem release have version 1.0?

Found this related post, https://stackoverflow.com/questions/7139/should-a-first-release-be-an-0-1-version-or-1-0b, but it is not about Ruby Gems. I am asking about the best and common practice for Ruby Gems.
I'll start with 0.0.1, and probably get to 0.0.10 when it is fully tested and ready for use.
Does it make sense to leave the version at 0.x.x? Or does that mean that the gem is beta and not stable and not ready for use? Is it better to set the version to 1.0.0?
Hosting on RubyGems and GitHub.
Thanks to matt, the docs at semver.org say that yes, release software should be at least v1.0.

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