# HG changeset patch
# User Matt Mackall <mpm@selenic.com>
# Date 2010-06-03 23:00:15
# Node ID b724b8467b82578a56ca04949f4d8b7d562fa35c
# Parent  a5eb0bf7e1581950a27e1f6e2ad3c50af9a49542

walkchangerevs: allow empty query sets

diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -1024,6 +1024,8 @@ def walkchangerevs(repo, match, opts, pr
     else:
         defrange = '-1:0'
     revs = revrange(repo, opts['rev'] or [defrange])
+    if not revs:
+        return []
     wanted = set()
     slowpath = match.anypats() or (match.files() and opts.get('removed'))
     fncache = {}