This enhancement allows a user to add the -s flag if they want to acc…

…ess a methods origin definition. It allows for chaining of multiple esses to further go up the classes as needed. (#770)

lib/irb/cmd/show_source.rb

@@ -27,11 +27,18 @@ def execute(str = nil)
           puts "Error: Expected a string but got #{str.inspect}"
           return
         end
-
-        source = SourceFinder.new(@irb_context).find_source(str)
+        if str.include? " -s"
+          str, esses = str.split(" -")
+          s_count = esses.count("^s").zero? ? esses.size : 1
+          source = SourceFinder.new(@irb_context).find_source(str, s_count)
+        else
+          source = SourceFinder.new(@irb_context).find_source(str)
+        end
 
         if source
           show_source(source)
+        elsif s_count
+          puts "Error: Couldn't locate a super definition for #{str}"
         else
           puts "Error: Couldn't locate a definition for #{str}"
         end

lib/irb/source_finder.rb

@@ -16,7 +16,7 @@ def initialize(irb_context)
       @irb_context = irb_context
     end
 
-    def find_source(signature)
+    def find_source(signature, s_count = nil)
       context_binding = @irb_context.workspace.binding
       case signature
       when /\A[A-Z]\w*(::[A-Z]\w*)*\z/ # Const::Name
@@ -26,14 +26,13 @@ def find_source(signature)
       when /\A(?<owner>[A-Z]\w*(::[A-Z]\w*)*)#(?<method>[^ :.]+)\z/ # Class#method
         owner = eval(Regexp.last_match[:owner], context_binding)
         method = Regexp.last_match[:method]
-        if owner.respond_to?(:instance_method)
-          methods = owner.instance_methods + owner.private_instance_methods
-          file, line = owner.instance_method(method).source_location if methods.include?(method.to_sym)
-        end
+        return unless owner.respond_to?(:instance_method)
+        file, line = method_target(owner, s_count, method, "owner")
       when /\A((?<receiver>.+)(\.|::))?(?<method>[^ :.]+)\z/ # method, receiver.method, receiver::method
         receiver = eval(Regexp.last_match[:receiver] || 'self', context_binding)
         method = Regexp.last_match[:method]
-        file, line = receiver.method(method).source_location if receiver.respond_to?(method, true)
+        return unless receiver.respond_to?(method, true)
+        file, line = method_target(receiver, s_count, method, "receiver")
       end
       if file && line && File.exist?(file)
         Source.new(file: file, first_line: line, last_line: find_end(file, line))
@@ -60,5 +59,24 @@ def find_end(file, first_line)
       end
       first_line
     end
+
+    def method_target(owner_receiver, s_count, method, type)
+      case type
+      when "owner"
+        target_method = owner_receiver.instance_method(method)
+        return target_method.source_location unless s_count
+      when "receiver"
+        if s_count
+          target_method = owner_receiver.class.instance_method(method)
+        else
+          target_method = method
+          return owner_receiver.method(method).source_location
+        end
+      end
+      s_count.times do |s|
+        target_method = target_method.super_method if target_method
+      end
+      target_method.nil? ? nil : target_method.source_location
+    end
   end
 end

test/irb/test_cmd.rb

@@ -466,6 +466,144 @@ def test_show_source_method
       assert_match(%r[/irb\/init\.rb], out)
     end
 
+    def test_show_source_method_s
+      code = <<~RUBY
+        class Baz
+          def foo
+          end
+        end
+      
+        class Bar < Baz
+          def foo
+            super
+          end
+        end
+      RUBY
+      File.write("#{@tmpdir}/bazbar.rb", code)
+      out, err = execute_lines(
+        "irb_load '#{@tmpdir}/bazbar.rb'\n",
+        "show_source Bar#foo -s",
+      )
+      assert_match(%r[bazbar.rb:2\n\n  def foo\n  end\n\n=> nil\n], out)
+      File.delete("#{@tmpdir}/bazbar.rb")
+    end
+
+    def test_show_source_method_multiple_s
+      code = <<~RUBY
+        class Baz
+          def fob
+          end
+        end
+      
+        class Bar < Baz
+          def fob
+            super
+          end
+        end
+
+        class Bob < Bar
+          def fob
+            super
+          end
+        end
+      RUBY
+      File.write("#{@tmpdir}/bazbarbob.rb", code)
+      out, err = execute_lines(
+        "irb_load '#{@tmpdir}/bazbarbob.rb'\n",
+        "show_source Bob#fob -ss",
+      )
+      assert_match(%r[bazbarbob.rb:2\n\n  def fob\n  end\n\n=> nil\n], out)
+      File.delete("#{@tmpdir}/bazbarbob.rb")
+    end
+
+    def test_show_source_method_no_instance_method
+      code = <<~RUBY
+        class Baz
+        end
+      
+        class Bar < Baz
+          def fee
+            super
+          end
+        end
+      RUBY
+      File.write("#{@tmpdir}/bazbar.rb", code)
+      out, err = execute_lines(
+        "irb_load '#{@tmpdir}/bazbar.rb'\n",
+        "show_source Bar#fee -s",
+      )
+      assert_match(%r[Error: Couldn't locate a super definition for Bar#fee\n], out)
+      File.delete("#{@tmpdir}/bazbar.rb")
+    end
+
+    def test_show_source_method_exceeds_super_chain
+      code = <<~RUBY
+        class Baz
+          def fow
+          end
+        end
+      
+        class Bar < Baz
+          def fow
+            super
+          end
+        end
+      RUBY
+      File.write("#{@tmpdir}/bazbar.rb", code)
+      out, err = execute_lines(
+        "irb_load '#{@tmpdir}/bazbar.rb'\n",
+        "show_source Bar#fow -ss",
+      )
+      assert_match(%r[Error: Couldn't locate a super definition for Bar#fow\n], out)
+      File.delete("#{@tmpdir}/bazbar.rb")
+    end
+
+    def test_show_source_method_accidental_characters
+      code = <<~RUBY
+        class Baz
+          def fol
+          end
+        end
+      
+        class Bar < Baz
+          def fol
+            super
+          end
+        end
+      RUBY
+      File.write("#{@tmpdir}/bazbar.rb", code)
+      out, err = execute_lines(
+        "irb_load '#{@tmpdir}/bazbar.rb'\n",
+        "show_source Bar#fol -sddddd",
+      )
+
+      assert_match(%r[bazbar.rb:2\n\n  def fol\n  end\n\n=> nil\n], out)
+      File.delete("#{@tmpdir}/bazbar.rb")
+    end
+
+    def test_show_source_receiver_super
+      code = <<~RUBY
+        class Baz
+          def fot
+          end
+        end
+      
+        class Bar < Baz
+          def fot
+            super
+          end
+        end
+      RUBY
+      File.write("#{@tmpdir}/bazbar.rb", code)
+      out, err = execute_lines(
+        "irb_load '#{@tmpdir}/bazbar.rb'\n",
+        "bar = Bar.new",
+        "show_source bar.fot -s"
+      )
+      assert_match(%r[bazbar.rb:2\n\n  def fot\n  end\n\n=> nil\n], out)
+      File.delete("#{@tmpdir}/bazbar.rb")
+    end
+
     def test_show_source_string
       out, err = execute_lines(
         "show_source 'IRB.conf'\n",