From mboxrd@z Thu Jan 1 00:00:00 1970 From: Harald van Dijk Subject: Re: getopts doesn't properly update OPTIND when called from function Date: Mon, 01 Jun 2015 19:30:46 +0200 Message-ID: <556C96C6.5030600@gigawatt.nl> References: <20150529025809.GA16240@gondor.apana.org.au> <5567FE11.8060103@gigawatt.nl> <20150601062905.GB10460@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from hosting12.csv-networks.nl ([84.244.151.217]:36130 "EHLO hosting12.csv-networks.nl" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753476AbbFARa6 (ORCPT ); Mon, 1 Jun 2015 13:30:58 -0400 In-Reply-To: <20150601062905.GB10460@gondor.apana.org.au> Sender: dash-owner@vger.kernel.org List-Id: dash@vger.kernel.org To: Herbert Xu Cc: martijn@inlv.org, dash@vger.kernel.org On 01/06/2015 08:29, Herbert Xu wrote: > On Fri, May 29, 2015 at 07:50:09AM +0200, Harald van Dijk wrote: >> >> But the test script in this thread does invoke getopts with >> parameters that are the same in all invocations, and without >> modifying OPTIND. I don't see anything else in the normative >> sections that would make the result undefined or unspecified either. >> I do think the script is valid, and the results in dash should match >> those of other shells. > > The bash behaviour makes it impossible to call shell functions > that invoke getopts while in the middle of an getopts loop. > > IMHO the dash behaviour makes a lot more sense since a function > always brings with it a new set of parameters. That plus the > fact that this behaviour has been there since day one makes me > reluctant to change it since the POSIX wording is not all that > clear. True. Given that almost no shell supports that anyway, there can't be too many scripts that rely on it, but I did warn about the risk of breaking another type of existing scripts as well, I agree that's a real concern. One thing that doesn't really make sense, though: if the getopts internal state is local to a function, then OPTIND and OPTARG really should be too. Because they aren't, nested getopts loops already don't really work in a useful way in dash, because the inner loop overwrites the OPTIND and OPTARG variables. While OPTARG will typically be checked right at the start of the loop, before any inner loop executes, OPTIND is typically used at the end of the loop, in combination with the shift command. The current behaviour makes the OPTIND value in that case unreliable. So either way, I think something should change. But if you prefer to get clarification first about the intended meaning of the POSIX wording, that certainly seems reasonable to me. > Cheers,