--- a/hgext/fastannotate/revmap.py	Mon Jan 06 14:15:40 2025 -0500
+++ b/hgext/fastannotate/revmap.py	Sun Jan 05 21:03:17 2025 -0500
@@ -254,6 +254,6 @@
             f.seek(-_hshlen, io.SEEK_END)
             if f.tell() > len(revmap.HEADER):
                 hsh = f.read(_hshlen)
-    except IOError:
+    except OSError:
         pass
     return hsh