--- a/hgext3rd/evolve/obshistory.py	Wed Mar 04 16:30:19 2020 +0100
+++ b/hgext3rd/evolve/obshistory.py	Wed Mar 04 16:30:38 2020 +0100
@@ -14,6 +14,7 @@
     error,
     graphmod,
     logcmdutil,
+    mdiff,
     node as nodemod,
     obsutil,
     patch,
@@ -248,8 +249,8 @@
     basename = b"changeset-description"
     succname = b"changeset-description"
 
-    d = compat.strdiff(basedesc, succdesc, basename, succname)
-    uheaders, hunks = d
+    uheaders, hunks = mdiff.unidiff(basedesc, b'', succdesc, b'',
+                                    basename, succname, False)
 
     # Copied from patch.diff
     text = b''.join(sum((list(hlines) for hrange, hlines in hunks), []))