From 5cfd33f5e736110b5fb681c231e92954751c3e4a Mon Sep 17 00:00:00 2001
From: nils <48135649+Nilstrieb@users.noreply.github.com>
Date: Fri, 27 May 2022 13:30:48 +0200
Subject: [PATCH] Fix `metrics::Cow` provenance issue (#303)

---
 metrics/src/cow.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/metrics/src/cow.rs b/metrics/src/cow.rs
index 5ff200b5..88d9b70c 100644
--- a/metrics/src/cow.rs
+++ b/metrics/src/cow.rs
@@ -330,7 +330,9 @@ unsafe impl Cowable for str {
 
     #[inline]
     fn owned_into_parts(owned: String) -> (NonNull<u8>, Metadata) {
-        let mut owned = ManuallyDrop::new(owned);
+        // We need to go through Vec here to get provenance for the entire allocation
+        // instead of just the initialized parts.
+        let mut owned = ManuallyDrop::new(owned.into_bytes());
         let ptr = unsafe { NonNull::new_unchecked(owned.as_mut_ptr()) };
         let metadata = Metadata::from_owned(owned.len(), owned.capacity());
         (ptr, metadata)