mercurial/scmutil.py

--- a/mercurial/scmutil.py	Fri Feb 08 13:33:40 2019 -0800
+++ b/mercurial/scmutil.py	Sat Feb 09 14:37:58 2019 -0800
@@ -795,8 +795,6 @@
     '''Return a matcher and the patterns that were used.
     The matcher will warn about bad matches, unless an alternate badfn callback
     is provided.'''
-    if pats == ("",):
-        pats = []
     if opts is None:
         opts = {}
     if not globbed and default == 'relpath':