mercurial/scmutil.py

--- a/mercurial/scmutil.py	Fri Feb 08 13:00:28 2019 -0800
+++ b/mercurial/scmutil.py	Fri Feb 08 13:33:40 2019 -0800
@@ -802,8 +802,9 @@
     if not globbed and default == 'relpath':
         pats = expandpats(pats or [])
 
+    uipathfn = getuipathfn(ctx.repo(), legacyrelativevalue=True)
     def bad(f, msg):
-        ctx.repo().ui.warn("%s: %s\n" % (m.rel(f), msg))
+        ctx.repo().ui.warn("%s: %s\n" % (uipathfn(f), msg))
 
     if badfn is None:
         badfn = bad