[ruby/irb] use RubyLex::TerminateLineInput appropriately [Bug #17564]

* using the appropriciate exception instead of `break` so that the session
  can be continue after the `irb_source` and `irb_load` commands
* suppress extra new line due to one more `#prompt` call

https://github.com/ruby/irb/commit/bdefaa7cfd

lib/irb.rb

@@ -525,7 +525,7 @@ module IRB
                 printf "Use \"exit\" to leave %s\n", @context.ap_name
               end
             else
-              print "\n"
+              print "\n" if @context.prompting?
             end
           end
           l

lib/irb/ruby-lex.rb

@@ -233,7 +233,7 @@ class RubyLex
             @line.force_encoding(@io.encoding)
             yield @line, @exp_line_no
           end
-          break if @io.eof?
+          raise TerminateLineInput if @io.eof?
           @line = ''
           @exp_line_no = @line_no
 

test/irb/test_cmd.rb

@@ -275,5 +275,59 @@ module TestIRB
       assert_empty err
       assert_match(/\A=> 3\nCUSTOM is added\.\n=> nil\ncustom processing time: .+\n=> 3\n=> nil\n=> 3\n/, out)
     end
+
+    def test_irb_source
+      IRB.init_config(nil)
+      File.write("#{@tmpdir}/a.rb", "a = 'hi'\n")
+      input = TestInputMethod.new([
+          "a = 'bug17564'\n",
+          "a\n",
+          "irb_source '#{@tmpdir}/a.rb'\n",
+          "a\n",
+        ])
+      IRB.conf[:PROMPT_MODE] = :SIMPLE
+      irb = IRB::Irb.new(IRB::WorkSpace.new, input)
+      IRB.conf[:MAIN_CONTEXT] = irb.context
+      out, err = capture_output do
+        irb.eval_input
+      end
+      assert_empty err
+      assert_pattern_list([
+          /=> "bug17564"\n/,
+          /=> "bug17564"\n/,
+          />> a = 'hi'\n/,
+          /=> "hi"\n/,
+          />> \n/,
+          /=> nil\n/,
+          /=> "hi"\n/,
+        ], out)
+    end
+
+    def test_irb_load
+      IRB.init_config(nil)
+      File.write("#{@tmpdir}/a.rb", "a = 'hi'\n")
+      input = TestInputMethod.new([
+          "a = 'bug17564'\n",
+          "a\n",
+          "irb_load '#{@tmpdir}/a.rb'\n",
+          "a\n",
+        ])
+      IRB.conf[:PROMPT_MODE] = :SIMPLE
+      irb = IRB::Irb.new(IRB::WorkSpace.new, input)
+      IRB.conf[:MAIN_CONTEXT] = irb.context
+      out, err = capture_output do
+        irb.eval_input
+      end
+      assert_empty err
+      assert_pattern_list([
+          /=> "bug17564"\n/,
+          /=> "bug17564"\n/,
+          />> a = 'hi'\n/,
+          /=> "hi"\n/,
+          />> \n/,
+          /=> nil\n/,
+          /=> "bug17564"\n/,
+        ], out)
+    end
   end
 end