diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -1119,7 +1119,8 @@ class changeset_printer(object):
         self.lastheader = None
         self.footer = None
 
-    def flush(self, rev):
+    def flush(self, ctx):
+        rev = ctx.rev()
         if rev in self.header:
             h = self.header[rev]
             if h != self.lastheader:
@@ -2156,7 +2157,7 @@ def displaygraph(ui, dag, displayer, sho
         lines = displayer.hunk.pop(rev).split('\n')
         if not lines[-1]:
             del lines[-1]
-        displayer.flush(rev)
+        displayer.flush(ctx)
         edges = edgefn(type, char, lines, seen, rev, parents)
         for type, char, lines, coldata in edges:
             graphmod.ascii(ui, state, type, char, lines, coldata)
diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -4627,7 +4627,7 @@ def log(ui, repo, *pats, **opts):
         else:
             revmatchfn = None
         displayer.show(ctx, copies=copies, matchfn=revmatchfn)
-        if displayer.flush(rev):
+        if displayer.flush(ctx):
             count += 1
 
     displayer.close()