Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754877AbbGCKQa (ORCPT ); Fri, 3 Jul 2015 06:16:30 -0400 Received: from mail-ob0-f170.google.com ([209.85.214.170]:35099 "EHLO mail-ob0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754288AbbGCKQY (ORCPT ); Fri, 3 Jul 2015 06:16:24 -0400 MIME-Version: 1.0 In-Reply-To: References: Date: Fri, 3 Jul 2015 12:16:23 +0200 Message-ID: Subject: Re: Kconfig: '+config' valid syntax? From: Ulf Magnusson To: Valentin Rothberg Cc: rafael.j.wysocki@intel.com, Paul Bolle , yann.morin.1998@free.fr, linux-kbuild@vger.kernel.org, Kernel Mailing List , Andreas Ruprecht , hengelein Stefan , linux@dominikbrodowski.net Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1846 Lines: 49 On Thu, Jul 2, 2015 at 10:08 AM, Valentin Rothberg wrote: > Hi, > > commit ed013214afa7 ("ACPI / init: Make it possible to override _REV") > is in today's linux-next tree (i.e., next-20150702) adding the > following hunk to drivers/acpi/Kconfig: > > --- a/drivers/acpi/Kconfig > +++ b/drivers/acpi/Kconfig > @@ -428,6 +428,26 @@ config XPOWER_PMIC_OPREGION > help > This config adds ACPI operation region support for XPower AXP288 PMIC. > > ++config ACPI_REV_OVERRIDE_POSSIBLE > + bool "Allow supported ACPI revision to be overriden" > + depends on X86 > + default y > [...] > > By having a close look at the first added line, we can see that > '+config ACPI_...' is added. To my great surprise, it's valid Kconfig > syntax. How is that possible? IMHO it's an invalid token, such that > Kconfig should complain about it. Or do I miss something? > > Kind regards, > Valentin For another take on this, you could look at the Config._tokenize() function in Kconfiglib (https://github.com/ulfalizer/Kconfiglib/blob/master/kconfiglib.py). Here's a relevant comment from that function: # The initial word on a line is parsed specially. Let # command_chars = [A-Za-z0-9_]. Then # - leading non-command_chars characters are ignored, and # - the first token consists the following one or more # command_chars characters. # This is why things like "----help--" are accepted. The root cause is sloppy lexing in zconf.l, IIRC. I didn't check whether it's been improved, but Kconfiglib needs to be backwards compatible either way. /Ulf -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/