Why text "2e8" is treated as String by YAML on Mac but as Float on Linux in Ruby?

Question

For the same ruby version, the same YAML parser engine Psych (but different minor versions), but different OS (Mac vs. Linux), text "2e8" is treated as String on Mac but as Float (200000000.0) on Linux. Why? How can I fix it so they show the same behavior?

• For Mac: Darwin 12.4.0 Darwin Kernel Version 12.4.0: root:xnu-2050.24.15~1/RELEASE_X86_64 x86_64

  require "yaml"
  RUBY_VERSION # => "1.9.3"
  YAML::ENGINE.yamler # => "psych"
  Psych::VERSION # => "1.2.2"
  
  Psych.load("2e8") # => "2e8"
  YAML.load("2e8") # => "2e8"
  YAML.load("'2e8'") # => "2e8"
  

• For Linux: Linux 2.6.18-238.el5 #1 SMP x86_64 GNU/Linux

  require "yaml"
  RUBY_VERSION # => "1.9.3"
  YAML::ENGINE.yamler # => "psych"
  Psych::VERSION # => "1.2.1"
  
  Psych.load("2e8") # => 200000000.0
  YAML.load("2e8") # => 200000000.0
  YAML.load("'2e8'") # => "2e8"
  

I know adding quotes '2e8' will give the same behavior, but this text is part of a dump generated on Mac, which doesn't put these quotes.

Answer 1

It is the psych version that is causing the difference.

This is the relevant commit: https://github.com/tenderlove/psych/commit/2422a9fc3aeff3c60c6510efbf655a34218c7605

You are about two years behind latest version, so I suggest if you can to update your dependencies on the project.

How did I find this? Using github's excellent compare function: https://github.com/tenderlove/psych/compare/v1.2.1...v1.2.2