Make ls command work for BasicObjects (#1177)

* Add ls command test

* Make ls command work for BasicObjects

* Use is_a? to determine if obj is a Class or Module

* Use === operator to determin if obj is a Class or Module

Author: eikes

lib/irb/command/ls.rb

@@ -55,19 +55,21 @@ def execute(arg)
 
         o = Output.new(grep: grep)
 
-        klass  = (obj.class == Class || obj.class == Module ? obj : obj.class)
+        klass = Kernel.instance_method(:class).bind(obj).call
+        obj_is_class_or_module = Module === obj
+        klass = obj_is_class_or_module ? obj : klass
 
-        o.dump("constants", obj.constants) if obj.respond_to?(:constants)
+        o.dump("constants", obj.constants) if obj_is_class_or_module
         dump_methods(o, klass, obj)
-        o.dump("instance variables", obj.instance_variables)
+        o.dump("instance variables", Kernel.instance_method(:instance_variables).bind(obj).call)
         o.dump("class variables", klass.class_variables)
         o.dump("locals", locals) if locals
         o.print_result
       rescue EvaluationError
       end
 
       def dump_methods(o, klass, obj)
-        singleton_class = begin obj.singleton_class; rescue TypeError; nil end
+        singleton_class = begin Kernel.instance_method(:singleton_class).bind(obj).call; rescue TypeError; nil end
         dumped_mods = Array.new
         ancestors = klass.ancestors
         ancestors = ancestors.reject { |c| c >= Object } if klass < Object

test/irb/command/test_ls.rb

@@ -0,0 +1,71 @@
+require "tempfile"
+require_relative "../helper"
+
+module TestIRB
+  class LSTest < IntegrationTestCase
+    def setup
+      super
+
+      write_ruby <<~'RUBY'
+        class Foo
+          class Bar
+            def bar
+              "this is bar"
+            end
+          end
+
+          def foo
+            "this is foo"
+          end
+        end
+
+        class BO < BasicObject
+          ONE = 1
+          def baz
+            "this is baz"
+          end
+        end
+
+        binding.irb
+      RUBY
+    end
+
+    def test_ls_class
+      out = run_ruby_file do
+        type "ls Foo"
+        type "exit"
+      end
+
+      assert_match(/constants: Bar/, out)
+      assert_match(/Foo#methods: foo/, out)
+    end
+
+    def test_ls_instance
+      out = run_ruby_file do
+        type "ls Foo.new"
+        type "exit"
+      end
+
+      assert_match(/Foo#methods: foo/, out)
+    end
+
+    def test_ls_basic_object
+      out = run_ruby_file do
+        type "ls BO"
+        type "exit"
+      end
+
+      assert_match(/constants:.*ONE/, out)
+      assert_match(/BO#methods: baz/, out)
+    end
+
+    def test_ls_basic_object_instance
+      out = run_ruby_file do
+        type "ls BO.new"
+        type "exit"
+      end
+
+      assert_match(/BO#methods: baz/, out)
+    end
+  end
+end