--- a/mercurial/revlog.py	Mon May 03 12:25:56 2021 +0200
+++ b/mercurial/revlog.py	Mon May 03 12:26:06 2021 +0200
@@ -485,13 +485,13 @@
         self._initempty = True
         indexdata = self._get_data(self._indexfile, mmapindexthreshold)
         if len(indexdata) > 0:
-            versionflags = INDEX_HEADER.unpack(indexdata[:4])[0]
+            header = INDEX_HEADER.unpack(indexdata[:4])[0]
             self._initempty = False
         else:
-            versionflags = newversionflags
-
-        flags = self._format_flags = versionflags & ~0xFFFF
-        fmt = self._format_version = versionflags & 0xFFFF
+            header = newversionflags
+
+        flags = self._format_flags = header & ~0xFFFF
+        fmt = self._format_version = header & 0xFFFF
 
         if fmt == REVLOGV0:
             if flags:
@@ -510,8 +510,8 @@
                     % (flags >> 16, fmt, self.display_id)
                 )
 
-            self._inline = versionflags & FLAG_INLINE_DATA
-            self._generaldelta = versionflags & FLAG_GENERALDELTA
+            self._inline = header & FLAG_INLINE_DATA
+            self._generaldelta = header & FLAG_GENERALDELTA
 
         elif fmt == REVLOGV2:
             if flags & ~REVLOGV2_FLAGS: