irb.rb: restore the last error

* lib/irb.rb (eval_input): restore the last error `$!`, as the
  previous result.  [Feature #14684]

* lib/irb/context.rb (evaluate): add `exception` keyword argument
  to set the last error.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63150 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 9 insertions, 0 deletions

diff --git a/test/irb/test_context.rb b/test/irb/test_context.rb
index 35141a41a4..1faf2b373d 100644
--- a/test/irb/test_context.rb
+++ b/test/irb/test_context.rb
@@ -40,5 +40,14 @@ module TestIRB
       assert_same(obj, @context.last_value)
       assert_same(obj, @context.evaluate('_', 1))
     end
+
+    def test_evaluate_with_exception
+      assert_nil(@context.evaluate("$!", 1))
+      e = assert_raise_with_message(RuntimeError, 'foo') {
+        @context.evaluate("raise 'foo'", 1)
+      }
+      assert_equal('foo', e.message)
+      assert_same(e, @context.evaluate('$!', 1, exception: e))
+    end
   end
 end