From c1f024f99d4f24dde4ca3c1f35825eba19c413f6 Mon Sep 17 00:00:00 2001
From: Jean Boussier <jean.boussier@gmail.com>
Date: Thu, 30 Jan 2025 09:34:01 +0100
Subject: [PATCH] [ruby/psych] Avoid calls to `require` in hotspots

Followup: https://github.com/ruby/psych/pull/686

This single call shows up as 4% of some controller actions
in the lobsters benchmark.

Profile: https://share.firefox.dev/3EqKnhS

https://github.com/ruby/psych/commit/b77bfee092
---
 ext/psych/lib/psych/nodes/node.rb | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ext/psych/lib/psych/nodes/node.rb b/ext/psych/lib/psych/nodes/node.rb
index 1a4ea5531f..6ae5c59148 100644
--- a/ext/psych/lib/psych/nodes/node.rb
+++ b/ext/psych/lib/psych/nodes/node.rb
@@ -55,7 +55,8 @@ module Psych
       #
       # See also Psych::Visitors::Emitter
       def yaml io = nil, options = {}
-        require "stringio"
+        require "stringio" unless defined?(StringIO)
+
         real_io = io || StringIO.new(''.encode('utf-8'))
 
         Visitors::Emitter.new(real_io, options).accept self