# HG changeset patch
# User John Li <jli@circularly.org>
# Date 2012-08-22 15:18:35
# Node ID 45b5eb2941d0d35863a96d13ce11a55be1825c68
# Parent  b32a30da608d529a0ebbde364f291c5ef107a6b4

merge: handle case when heads are all bookmarks

If all heads are bookmarks, merge fails to find what node to merge
with (throws an IndexError while indexing into the non-bookmark heads
list) as of 4a02cf4fbb2e. This catches that case and prints an error
to specify a rev explicitly.

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -4269,7 +4269,7 @@ def merge(ui, repo, node=None, **opts):
                              hint=_("run 'hg heads .' to see heads"))
 
         parent = repo.dirstate.p1()
-        if len(nbhs) == 1:
+        if len(nbhs) <= 1:
             if len(bheads) > 1:
                 raise util.Abort(_("heads are bookmarked - "
                                    "please merge with an explicit rev"),