From 0c436bbfbf3b28fab8abfcbda9b8f388fa22290a Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Mon, 20 Jan 2020 00:41:56 +0900
Subject: Recheck array length after `to_str` conversion

https://hackerone.com/reports/244787
---
 test/ruby/test_array.rb | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'test/ruby')

diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index c3b842e950..fcfda92487 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -2457,6 +2457,17 @@ class TestArray < Test::Unit::TestCase
     assert_equal("ab012z", x.ary.join(""))
   end
 
+  def test_join_recheck_array_length
+    x = Struct.new(:ary).new
+    def x.to_str
+      ary.clear
+      ary[0] = "b"
+      "z"
+    end
+    x.ary = Array.new(1023) {"a"*1} << x
+    assert_equal("b", x.ary.join(""))
+  end
+
   def test_to_a2
     klass = Class.new(Array)
     a = klass.new.to_a
-- 
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