From 16cd0de6ec8464129041c52174f5608e32512ca1 Mon Sep 17 00:00:00 2001
From: Jeremy Evans <code@jeremyevans.net>
Date: Sat, 17 Aug 2019 22:47:43 -0700
Subject: [PATCH] When splitting a keyword hash, dup it first to not mutate it

---
 vm_args.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/vm_args.c b/vm_args.c
index a91db40cf9..69be10a2b6 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -241,6 +241,7 @@ keyword_hash_p(VALUE *kw_hash_ptr, VALUE *rest_hash_ptr, int check_only_symbol)
 		*kw_hash_ptr = Qnil;
 		return FALSE;
 	    case KW_HASH_HAS_BOTH_KEYS:
+                *rest_hash_ptr = rb_hash_dup(*rest_hash_ptr);
 		keyword_hash_split(kw_hash_ptr, rest_hash_ptr);
 		return TRUE;
 	    }