From d3ff43852b22f5463d22aab390ef340d9ebe4b06 Mon Sep 17 00:00:00 2001
From: Peter Zhu <peter@peterzhu.ca>
Date: Thu, 29 Jun 2023 15:25:31 -0400
Subject: Fix memory leak in Hash#replace

Hash#replace can leak memory if the receiver has an ST table.
---
 hash.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

(limited to 'hash.c')

diff --git a/hash.c b/hash.c
index a779c6f218..f3514cd94b 100644
--- a/hash.c
+++ b/hash.c
@@ -1158,6 +1158,19 @@ ar_clear(VALUE hash)
     }
 }
 
+static void
+st_free_and_clear_table(VALUE hash)
+{
+    HASH_ASSERT(RHASH_ST_TABLE_P(hash));
+
+    st_table *tab = RHASH_ST_TABLE(hash);
+
+    if (tab->bins != NULL) free(tab->bins);
+    free(tab->entries);
+
+    RHASH_ST_CLEAR(hash);
+}
+
 typedef int st_foreach_func(st_data_t, st_data_t, st_data_t);
 
 struct foreach_safe_arg {
@@ -2894,7 +2907,7 @@ rb_hash_replace(VALUE hash, VALUE hash2)
         ar_free_and_clear_table(hash);
     }
     else {
-        RHASH_ST_CLEAR(hash);
+        st_free_and_clear_table(hash);
     }
 
     hash_copy(hash, hash2);
-- 
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