When a Ruby version gem has a letter in its version number, it is considered a pre-release:
1.0.0.rc12.3.0.alpha23.0.0.beta34.0.0.pre.rc2
Even if a pre-release gem has the highest version number, it is never installed unless the user explictily requested the version:
gem install foobar --version="=2.3.0.alpha2"
Also bundle update will never update a stable version to a pre-release version unless the user explicitly requests it in the Gemfile:
gem 'foobar', '=2.3.0.alpha2'
A note on Semantic Versioning
Semantic Versioning
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has a naming convention for pre-releases that is incompatible with that from RubyGems. In Semantic Versioning, the version number and pre-release identifier (like rc1) must be separated by a dash, e.g. 1.0.0-rc1. However, RubyGems versions require version components to be separated by a dot.
When RubyGems sees a version number with a dash, it automatically converts it to a RubyGems-compatible version like this:
| Semantic versioning | Converted RubyGems version |
|---|---|
1.0.0-rc1 |
1.0.0.pre.rc1 |
2.3.0-alpha2 |
2.3.0.pre.alpha2 |
3.0.0-beta3 |
3.0.0.pre.beta3 |
Note that npm packages force you to use Semantic Versioning's naming convention. If your library has both a Ruby and JavaScript component and you want to use the same version constant for both, you can use the npm's convention and let RubyGems auto-convert its own variant.
See also
