feat(tvix/castore/import): remove copying in find_ancestor r/7910

We don't need to copy if we explicitly say that the returned
Option<Path> may hold onto bytes from the passed in &DirEntry.

Change-Id: Ib46b6fd2f8f19a45f8bef79c4c1d2fa6b490cad7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11410
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI

1 files changed, 2 insertions, 8 deletions

diff --git a/tvix/castore/src/import.rs b/tvix/castore/src/import.rs
index a7034af19f5c..f78029ee0e3a 100644
--- a/tvix/castore/src/import.rs
+++ b/tvix/castore/src/import.rs
@@ -284,14 +284,8 @@ impl MerkleInvariantChecker {
     }
 
     /// Returns a potential ancestor already seen for that directory entry.
-    fn find_ancestor(&self, node: &DirEntry) -> Option<PathBuf> {
-        for anc in node.path().ancestors() {
-            if self.seen.contains(anc) {
-                return Some(anc.to_owned());
-            }
-        }
-
-        None
+    fn find_ancestor<'a>(&self, node: &'a DirEntry) -> Option<&'a Path> {
+        node.path().ancestors().find(|p| self.seen.contains(*p))
     }
 }