More complicated gsub to handle empty lines' unescaping correctly

Author: os97673

ChangeLog.md

@@ -1,3 +1,8 @@
+## [0.4.30](https://github.com/ruby-debug/ruby-debug-ide/compare/v0.4.29...v0.4.30)
+
+* unescaping of empty line fixed
+  [RUBY-16600](https://youtrack.jetbrains.com/issue/RUBY-16600)
+
 ## [0.4.29](https://github.com/ruby-debug/ruby-debug-ide/compare/v0.4.28...v0.4.29)
 
 * Fixed problem with evaluating "%"

lib/ruby-debug-ide/command.rb

@@ -66,8 +66,9 @@ def options
       end
 
       def unescape_incoming(str)
-        str.gsub(/((?:^|[^\\])(?:\\\\)*)\\n/, "\\1\n").
-            gsub(/\\\\/, '\\')
+        str.gsub(/((?:^|[^\\])(?:\\\\)*)((?:\\n)+)/) do |_|
+          $1 + "\n" * ($2.size / 2)
+        end.gsub(/\\\\/, '\\')
       end
     end
 

test/ruby-debug/unescape_incoming_test.rb

@@ -28,6 +28,10 @@ def test_something
     do_test('"\\\\\\n".size', "\"\\\n\".size")
   end
 
+  def test_two_newlines
+    do_test('hello\n\nworld', "hello\n\nworld")
+  end
+
   def do_test(input, expected_result)
     assert_equal(expected_result, Debugger::Command.unescape_incoming(input))
   end