From f513863c8186ebfbc2a4264929287f982fd147ea Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Sat, 26 Oct 2024 21:08:55 +0900
Subject: [PATCH] [ruby/stringio] Unreachable after an invalid argument
 exception

https://github.com/ruby/stringio/commit/a2aab4721c
---
 ext/stringio/stringio.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index 863f9ab201..6f68e46cf1 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -952,7 +952,10 @@ strio_ungetc(VALUE self, VALUE c)
 
 	enc = rb_enc_get(ptr->string);
 	len = rb_enc_codelen(cc, enc);
-	if (len <= 0) rb_enc_uint_chr(cc, enc);
+	if (len <= 0) {
+	    rb_enc_uint_chr(cc, enc); /* to raise an exception */
+	    UNREACHABLE;
+	}
 	rb_enc_mbcput(cc, buf, enc);
 	return strio_unget_bytes(ptr, buf, len);
     }