From 2b2e61e6f98f4dde3547a097241a950cb1300b86 Mon Sep 17 00:00:00 2001
From: Kevin Newton <kddnewton@gmail.com>
Date: Wed, 21 Feb 2024 10:28:58 -0500
Subject: [PATCH] [ruby/prism] Only call encoding_changed callback on change

https://github.com/ruby/prism/commit/7d0bea3ce0
---
 prism/prism.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/prism/prism.c b/prism/prism.c
index d829c984dd..ee3e3f0d5a 100644
--- a/prism/prism.c
+++ b/prism/prism.c
@@ -6605,9 +6605,12 @@ parser_lex_magic_comment_encoding_value(pm_parser_t *parser, const uint8_t *star
     const pm_encoding_t *encoding = pm_encoding_find(start, end);
 
     if (encoding != NULL) {
-        parser->encoding = encoding;
+        if (parser->encoding != encoding) {
+            parser->encoding = encoding;
+            if (parser->encoding_changed_callback != NULL) parser->encoding_changed_callback(parser);
+        }
+
         parser->encoding_changed = (encoding != PM_ENCODING_UTF_8_ENTRY);
-        if (parser->encoding_changed_callback != NULL) parser->encoding_changed_callback(parser);
         return true;
     }