diff -r e308439339e2 -r 0ad269e24075 mercurial/store.py
--- a/mercurial/store.py	Mon Oct 14 15:11:49 2024 +0200
+++ b/mercurial/store.py	Tue Oct 01 15:55:29 2024 +0200
@@ -485,8 +485,8 @@
         size = self.file_size(None)
 
         def get_stream():
-            actual_path = volatiles[vfs.join(self.unencoded_path)]
-            with open(actual_path, 'rb') as fp:
+            path = vfs.join(self.unencoded_path)
+            with volatiles.open(path) as fp:
                 yield None  # ready to stream
                 if size <= 65536:
                     yield fp.read(size)