--- a/mercurial/logcmdutil.py	Sat Feb 09 23:48:19 2019 -0800
+++ b/mercurial/logcmdutil.py	Thu Jan 31 15:35:51 2019 -0800
@@ -99,6 +99,9 @@
         width = 80
         if not ui.plain():
             width = ui.termwidth() - graphwidth
+        # If an explicit --root was given, don't respect ui.relative-paths
+        if not relroot:
+            pathfn = compose(scmutil.getuipathfn(repo), pathfn)
 
     chunks = ctx2.diff(ctx1, match, changes, opts=diffopts, pathfn=pathfn,
                        copysourcematch=copysourcematch,