815 

   816     # merge helper

   817     ui.status(_("Checking merge helper...\n"))

   818     cmd = (os.environ.get("HGMERGE") or ui.config("ui", "merge")

   819            or "hgmerge")

   820     cmdpath = util.find_exe(cmd) or util.find_exe(cmd.split()[0])

   821     if not cmdpath:

   822         if cmd == 'hgmerge':

   823             ui.write(_(" No merge helper set and can't find default"

   824                        " hgmerge script in PATH\n"))

   825             ui.write(_(" (specify a merge helper in your .hgrc file)\n"))

   826         else:

   827             ui.write(_(" Can't find merge helper '%s' in PATH\n") % cmd)

   828             ui.write(_(" (specify a merge helper in your .hgrc file)\n"))

   829             problems += 1

   830     else:

   831         # actually attempt a patch here

   832         fa = writetemp("1\n2\n3\n4\n")

   833         fl = writetemp("1\n2\n3\ninsert\n4\n")

   834         fr = writetemp("begin\n1\n2\n3\n4\n")

   835         r = util.system('%s "%s" "%s" "%s"' % (cmd, fl, fa, fr))

   836         if r:

   837             ui.write(_(" Got unexpected merge error %d!\n") % r)

   838             problems += 1

   839         m = file(fl).read()

   840         if m != "begin\n1\n2\n3\ninsert\n4\n":

   841             ui.write(_(" Got unexpected merge results!\n"))

   842             ui.write(_(" (your merge helper may have the"

   843                        " wrong argument order)\n"))

   844             ui.write(_(" Result: %r\n") % m)

   845             problems += 1

   846         os.unlink(fa)

   847         os.unlink(fl)

   848         os.unlink(fr)