diff --git a/rust/hg-cpython/src/dirstate/dirstate_map.rs b/rust/hg-cpython/src/dirstate/dirstate_map.rs
index f808fa119212f553cfbc977b2a4b953fdab4b8f3_cnVzdC9oZy1jcHl0aG9uL3NyYy9kaXJzdGF0ZS9kaXJzdGF0ZV9tYXAucnM=..ccf5c44092db24a6391d6f5bf3bb82872b9ad9eb_cnVzdC9oZy1jcHl0aG9uL3NyYy9kaXJzdGF0ZS9kaXJzdGF0ZV9tYXAucnM= 100644
--- a/rust/hg-cpython/src/dirstate/dirstate_map.rs
+++ b/rust/hg-cpython/src/dirstate/dirstate_map.rs
@@ -270,5 +270,5 @@
                 let tuple = (packed, tree_metadata, append);
                 Ok(tuple.to_py_object(py).into_object())
             },
-            Err(_) => Err(PyErr::new::<exc::OSError, _>(
+            Err(e) => Err(PyErr::new::<exc::OSError, _>(
                 py,
@@ -274,5 +274,5 @@
                 py,
-                "Dirstate error".to_string(),
+                e.to_string(),
             )),
         }
     }