Layout/EndOfLine does not choose correct default line ending

[enkessler]

The Layout/EndOfLine cop automatically decides the 'correct' line ending when set to :native. However, the logic used to make that decision does not come to the correct answer when using JRuby. The check being used is RuboCop::Platform.windows? which just does an inspection of RUBY_PLATFORM:

RUBY_PLATFORM =~ /cygwin|mswin|mingw|bccwin|wince|emx/

However, when using JRuby the value of RUBY_PLATFORM will be java, even when using Windows. This results in the cop deciding that it is in a non-Windows environment and thus check for 'lf' line endings instead of 'crlf'.

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Expected behavior

The Layout/EndOfLine cop should natively use 'crlf' line endings for Windows with JRuby.

Actual behavior

The Layout/EndOfLine cop natively uses 'lf' line endings for Windows with JRuby.

Steps to reproduce the problem

• use Windows
• use JRuby (9.1.17, in my case)
• have a Ruby file with crlf line endings

Run rubocop against the file and the generated report will contain violations for Layout/EndOfLine.

RuboCop version

0.63.1 (using Parser 2.6.0.0, running on jruby 2.3.3 java)

[mikegee]

Do you know how Rubocop can know the correct line ending on JRuby?

[enkessler]

Using RbConfig::CONFIG['host_os'] instead of using RUBY_PLATFORM seems to be the way. I get 'mswin32' when I check it instead of getting 'java', like I do RUBY_PLATFORM.

Edit: Gem.win_platform? could also work.

[Drenmi]

Thanks for the report and investigation @enkessler! 🙇 Would you be interested in opening a PR for this?

[enkessler]

I can take a crack at it some time this week, sure.