From 45f6e3521a2b4f535e29d03dd077978a691bdb58 Mon Sep 17 00:00:00 2001
From: Jade Lovelace <lix@jade.fyi>
Date: Sat, 9 Mar 2024 22:05:50 -0800
Subject: [PATCH] finally.hh: delete copy constructor which is a bad idea

Change-Id: I6d0b5736893c44bddc6f5789b452b434f8671b9b
---
 src/libutil/finally.hh | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/libutil/finally.hh b/src/libutil/finally.hh
index db654301f..49263ee6d 100644
--- a/src/libutil/finally.hh
+++ b/src/libutil/finally.hh
@@ -9,8 +9,15 @@ class Finally
 {
 private:
     Fn fun;
+    bool movedFrom = false;
 
 public:
     Finally(Fn fun) : fun(std::move(fun)) { }
-    ~Finally() { fun(); }
+    // Copying Finallys is definitely not a good idea and will cause them to be
+    // called twice.
+    Finally(Finally &other) = delete;
+    Finally(Finally &&other) : fun(std::move(other.fun)) {
+        other.movedFrom = true;
+    }
+    ~Finally() { if (!movedFrom) fun(); }
 };