lib/pessimize/version_mapper.rb in pessimize-0.4.0 vs lib/pessimize/version_mapper.rb in pessimize-0.5.0

@@ -1,11 +1,15 @@
 module Pessimize
   class VersionMapper
     def call(gems, versions, version_constraint)
       gems.each do |gem|
         if versions.has_key? gem.name
-          version_parts = versions[gem.name].split('.')
-          version = version_constraint == 'minor' ? version_parts.first(2).join('.') : version_parts.join('.')
+          version = versions[gem.name]
+          if !::Gem::Version.new(version).prerelease?
+            version_parts = versions[gem.name].split('.')
+            version_parts = version_constraint == 'minor' ? version_parts.first(2) : version_parts
+            version = version_parts.join('.')
+          end
           gem.version = "~> #{version}"
         end
       end
     end
   end