[ruby/json] Fix a regression in the parser with leading /

Ref: https://github.com/ruby/ruby/pull/12598

This could lead to an infinite loop.

https://github.com/ruby/json/commit/f8cfa2696a

1 files changed, 7 insertions, 0 deletions

diff --git a/test/json/json_parser_test.rb b/test/json/json_parser_test.rb
index 5956200893..c5ce02320f 100644
--- a/test/json/json_parser_test.rb
+++ b/test/json/json_parser_test.rb
@@ -629,6 +629,13 @@ class JSONParserTest < Test::Unit::TestCase
     end
   end
 
+  def test_parse_leading_slash
+    # ref: https://github.com/ruby/ruby/pull/12598
+    assert_raise(JSON::ParserError) do
+      JSON.parse("/foo/bar")
+    end
+  end
+
   private
 
   def string_deduplication_available?