irb.rb: update `_`

* lib/irb.rb (IRB::Irb#eval_input): update `_` after exception.
  [ruby-core:86989] [Bug #14749]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63409 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 23 insertions, 0 deletions

diff --git a/test/irb/test_context.rb b/test/irb/test_context.rb
index 75e47cf1e9..fa2432b3f3 100644
--- a/test/irb/test_context.rb
+++ b/test/irb/test_context.rb
@@ -22,6 +22,10 @@ module TestIRB
       def eof?
         @line_no >= @list.size
       end
+
+      def encoding
+        Encoding.default_external
+      end
     end
 
     def setup
@@ -49,5 +53,24 @@ module TestIRB
       assert_equal('foo', e.message)
       assert_same(e, @context.evaluate('$!', 1, exception: e))
     end
+
+    def test_eval_input
+      input = TestInputMethod.new([
+        "raise 'Foo'\n",
+        "_\n",
+        "0\n",
+        "_\n",
+      ])
+      irb = IRB::Irb.new(IRB::WorkSpace.new(Object.new), input)
+      out, err = capture_io do
+        irb.eval_input
+      end
+      assert_empty err
+      assert_pattern_list([:*, /RuntimeError \(.*Foo.*\).*\n/,
+                           :*, /#<RuntimeError: Foo>\n/,
+                           :*, /0$/,
+                           :*, /0$/,
+                           /\s*/], out)
+    end
   end
 end