diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1808,7 +1808,8 @@
                 if inline:
                     chunkstart += (rev + 1) * iosize
                 chunklength = length(rev)
-                ladd(decomp(buffer(data, chunkstart - offset, chunklength)))
+                c = buffer(data, chunkstart - offset, chunklength)
+                ladd(decomp(c))
 
         return l