Merge pull request #1722 from take-cheeze/hash_ext_arena_fix

Fix possible arena overflow in mruby-hast-ext.

mrbgems/mruby-hash-ext/src/hash-ext.c

@@ -23,12 +23,14 @@ static mrb_value
 hash_values_at(mrb_state *mrb, mrb_value hash)
 {
   mrb_value *argv, result;
-  int argc, i;
+  int argc, i, ai;
 
   mrb_get_args(mrb, "*", &argv, &argc);
   result = mrb_ary_new_capa(mrb, argc);
+  ai = mrb_gc_arena_save(mrb);
   for (i = 0; i < argc; i++) {
     mrb_ary_push(mrb, result, mrb_hash_get(mrb, hash, argv[i]));
+    mrb_gc_arena_restore(mrb, ai);
   }
   return result;
 }

mrbgems/mruby-hash-ext/test/hash.rb

@@ -21,4 +21,9 @@ end
 assert('Hash#values_at') do
   h = { "cat" => "feline", "dog" => "canine", "cow" => "bovine" }
   assert_equal ["bovine", "feline"], h.values_at("cow", "cat")
+
+  keys = []
+  (0...1000).each { |v| keys.push "#{v}" }
+  h = Hash.new { |hash,k| hash[k] = k }
+  assert_equal keys, h.values_at(*keys)
 end