diff --git a/mercurial/filemerge.py b/mercurial/filemerge.py
--- a/mercurial/filemerge.py
+++ b/mercurial/filemerge.py
@@ -515,7 +515,7 @@
                            (tool, fcd.path()))
         repo.ui.debug('launching merge tool: %s\n' % cmd)
         r = ui.system(cmd, cwd=repo.root, environ=env, blockedtag='mergetool')
-        repo.ui.debug('merge tool returned: %s\n' % r)
+        repo.ui.debug('merge tool returned: %d\n' % r)
         return True, r, False
     finally:
         util.unlink(b)
diff --git a/mercurial/mdiff.py b/mercurial/mdiff.py
--- a/mercurial/mdiff.py
+++ b/mercurial/mdiff.py
@@ -457,7 +457,7 @@
     # TODO: deltas
     ret = []
     ret.append('GIT binary patch\n')
-    ret.append('literal %s\n' % len(tn))
+    ret.append('literal %d\n' % len(tn))
     for l in chunk(zlib.compress(tn)):
         ret.append(fmtline(l))
     ret.append('\n')