diff -Nur -x '*.orig' -x '*.rej' rdiff-backup-1.1.5/rdiff_backup/metadata.py mezzanine_patched_rdiff-backup-1.1.5/rdiff_backup/metadata.py
--- rdiff-backup-1.1.5/rdiff_backup/metadata.py	2006-01-01 13:46:05.000000000 +1100
+++ mezzanine_patched_rdiff-backup-1.1.5/rdiff_backup/metadata.py	2006-10-05 12:35:42.894423015 +1000
@@ -375,7 +375,7 @@
 			self.fileobj = self.rp.open("rb", compress)
 		else:
 			assert mode == 'w'
-			if compress and not rp_base.isinccompressed():
+			if compress and rp_base.isincfile() and not rp_base.isinccompressed():
 				def callback(rp): self.rp = rp
 				self.fileobj = rpath.MaybeGzip(rp_base, callback)
 			else: