--- a/mercurial/mdiff.py
+++ b/mercurial/mdiff.py
@@ -18,16 +18,22 @@ def unidiff(a, ad, b, bd, fn, r=None, te
if not text and (util.binary(a) or util.binary(b)):
l = ['Binary file %s has changed\n' % fn]
- elif a == None:
+ elif not a:
b = b.splitlines(1)
- l1 = "--- %s\t%s\n" % ("/dev/null", epoch)
+ if a is None:
+ l1 = "--- %s\t%s\n" % ("/dev/null", epoch)
+ else:
+ l1 = "--- %s\t%s\n" % ("a/" + fn, ad)
l2 = "+++ %s\t%s\n" % ("b/" + fn, bd)
l3 = "@@ -0,0 +1,%d @@\n" % len(b)
l = [l1, l2, l3] + ["+" + e for e in b]
- elif b == None:
+ elif not b:
a = a.splitlines(1)
l1 = "--- %s\t%s\n" % ("a/" + fn, ad)
- l2 = "+++ %s\t%s\n" % ("/dev/null", epoch)
+ if b is None:
+ l2 = "+++ %s\t%s\n" % ("/dev/null", epoch)
+ else:
+ l2 = "+++ %s\t%s\n" % ("b/" + fn, bd)
l3 = "@@ -1,%d +0,0 @@\n" % len(a)
l = [l1, l2, l3] + ["-" + e for e in a]
else: