diff --git a/mercurial/dirstateutils/docket.py b/mercurial/dirstateutils/docket.py
--- a/mercurial/dirstateutils/docket.py
+++ b/mercurial/dirstateutils/docket.py
@@ -34,7 +34,7 @@
 
 
 class DirstateDocket(object):
-    data_filename_pattern = b'dirstate.%s.d'
+    data_filename_pattern = b'dirstate.%s'
 
     def __init__(self, parents, data_size, tree_metadata, uuid):
         self.parents = parents
diff --git a/rust/hg-core/src/dirstate_tree/on_disk.rs b/rust/hg-core/src/dirstate_tree/on_disk.rs
--- a/rust/hg-core/src/dirstate_tree/on_disk.rs
+++ b/rust/hg-core/src/dirstate_tree/on_disk.rs
@@ -265,7 +265,7 @@
     }
 
     pub fn data_filename(&self) -> String {
-        String::from_utf8(format_bytes!(b"dirstate.{}.d", self.uuid)).unwrap()
+        String::from_utf8(format_bytes!(b"dirstate.{}", self.uuid)).unwrap()
     }
 }