Filter out JRuby autogenerated aliases in ls [Fixes #474]

lib/pry/default_commands/ls.rb

@@ -35,6 +35,9 @@ class Pry
           opt.on :i, "ivars", "Show instance variables (in blue) and class variables (in bright blue)"
 
           opt.on :G, "grep", "Filter output by regular expression", :optional => false
+          if jruby?
+            opt.on :J, "all-java", "Show all the aliases for methods from java (default is to show only prettiest)"
+          end
         end
 
         def process
@@ -110,7 +113,58 @@ class Pry
 
         # Get all the methods that we'll want to output
         def all_methods(obj)
-          opts.present?(:'instance-methods') ? Pry::Method.all_from_class(obj) : Pry::Method.all_from_obj(obj)
+          methods = opts.present?(:'instance-methods') ? Pry::Method.all_from_class(obj) : Pry::Method.all_from_obj(obj)
+          if jruby? && !opts.present?(:J)
+            trim_jruby_aliases(methods)
+          else
+            methods
+          end
+        end
+
+        # JRuby creates lots of aliases for methods imported from java in an attempt to
+        # make life easier for ruby programmers.
+        # (e.g. getFooBar becomes get_foo_bar and foo_bar, and maybe foo_bar? if it
+        # returns a Boolean).
+        # The full transformations are in the assignAliases method of:
+        #   https://github.com/jruby/jruby/blob/master/src/org/jruby/javasupport/JavaClass.java
+        #
+        # This has the unfortunate side-effect of making the output of ls even more
+        # incredibly verbose than it normally would be for these objects; and so we filter
+        # out all but the nicest of these aliases here.
+        #
+        # TODO: This is a little bit vague, better heuristics could be used.
+        #       JRuby also has a lot of scala-specific logic, which we don't copy.
+        #
+        def trim_jruby_aliases(methods)
+          grouped = methods.group_by do |m|
+            m.name.sub(/\A(is|get|set)(?=[A-Z_])/, '').gsub(/[_?=]/, '').downcase
+          end
+
+          grouped.map do |key, values|
+            values = values.sort_by do |m|
+              rubbishness(m.name)
+            end
+
+            found = []
+            values.select do |x|
+              (!found.any?{ |y| x == y }) && found << x
+            end
+          end.flatten(1)
+        end
+
+        # When removing jruby aliases, we want to keep the alias that is "least rubbish"
+        # according to this metric.
+        def rubbishness(name)
+          name.each_char.map{ |x|
+            case x
+            when /[A-Z]/
+              1
+            when '?', '=', '!'
+              -2
+            else
+              0
+            end
+          }.inject(&:+) + (name.size / 100.0)
         end
 
         def resolution_order(obj)

test/test_default_commands/test_ls.rb

@@ -124,4 +124,18 @@ describe "ls" do
       end
     end
   end
+
+  if Pry::Helpers::BaseHelpers.jruby?
+    describe 'on java objects' do
+      it 'should omit java-esque aliases by default' do
+        mock_pry('ls java.lang.Thread.current_thread').should =~ / thread_group /
+        mock_pry('ls java.lang.Thread.current_thread').should.not =~ / getThreadGroup /
+      end
+
+      it 'should include java-esque aliases if requested' do
+        mock_pry('ls java.lang.Thread.current_thread -J').should =~ / thread_group /
+        mock_pry('ls java.lang.Thread.current_thread -J').should =~ / getThreadGroup /
+      end
+    end
+  end
 end