From 9e8d8aa19e4a2512042e8d1221ec9a0438c22e16 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Bennet=20Ble=C3=9Fmann?= <bb-github@t-online.de>
Date: Sat, 3 Aug 2024 19:36:05 +0200
Subject: [PATCH] prevent accidental double free by checking tag before drop

---
 src/arena.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/arena.rs b/src/arena.rs
index a3449d44..6acb279b 100644
--- a/src/arena.rs
+++ b/src/arena.rs
@@ -305,8 +305,10 @@ impl<T: ?Sized + ArenaAllocated> TypedArenaPtr<T> {
 
 impl<P, T: ?Sized + ArenaAllocated<Payload = ManuallyDrop<P>>> TypedArenaPtr<T> {
     pub fn drop_payload(&mut self) {
-        self.set_tag(ArenaHeaderTag::Dropped);
-        unsafe { ManuallyDrop::drop(&mut *self.as_ptr()) }
+        if self.get_tag() != ArenaHeaderTag::Dropped {
+            self.set_tag(ArenaHeaderTag::Dropped);
+            unsafe { ManuallyDrop::drop(&mut *self.as_ptr()) }
+        }
     }
 }
 
-- 
2.54.0