Support Jruby built-in global variables

[phs]

The white list of global variables accepted by the global variable cop should either be configurable or include standard globals from jruby:

config/setup_load_paths.rb:13:1: C: Do not introduce global variables.
$CLASSPATH << File.expand_path('../../classes', __FILE__)
^^^^^^^^^^

[phs]

As a workaround for rubocop noobs (like me), you can bracket the reference as so to get by:

# rubocop : disable AvoidGlobalVars
$CLASSPATH << File.expand_path('../../classes', __FILE__)
# rubocop : enable AvoidGlobalVars

[bbatsov]

Is there a list of the JRuby specific global vars somewhere?

[phs]

Yea, I couldn't find one either. The only one I'm using is $CLASSPATH.

How about it, @headius?

[headius]

Hmm...I don't know if we have compiled a list, but there's not many. A quick scan of all "$..." strings in JRuby gave me this list:

$CLASSPATH = mutable JRuby-local classpath array
$JRUBY_VERSION = JRuby version
$JRUBY_REVISION = JRuby git revision
$ENV_JAVA = JVM properties as a Hash-like

When using BSF to script Java: $bsf

And when ant support is loaded: $project

We also define all the aliases in English.rb immediately at startup ($LOADED_FEATURES, etc).

[bbatsov]

Thanks, @headius! I hope someday MRI will follow your lead and also define the aliases by default.

[phs]

Looks awesome, thanks! This might be a typo though.