t / t4135 / diff-with spaces.diffon commit builtin/reflog: convert tree_is_complete to take struct object_id (49a09e7)
   1--- post image.txt.orig 2010-08-18 20:13:31.544002255 -0500
   2+++ post image.txt      2010-08-18 20:13:31.544002255 -0500
   3@@ -1 +1 @@
   4-preimage
   5+postimage