From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthieu Moy Subject: Re: [PATCH v6 6/7] config: add `git_die_config()` to the config-set API Date: Thu, 31 Jul 2014 20:09:09 +0200 Message-ID: References: <1406821662-1570-1-git-send-email-tanayabh@gmail.com> <1406821662-1570-7-git-send-email-tanayabh@gmail.com> <53DA7281.8060403@gmail.com> <53DA7C23.3090603@gmail.com> Mime-Version: 1.0 Content-Type: text/plain Cc: git@vger.kernel.org, Ramkumar Ramachandra To: Tanay Abhra X-From: git-owner@vger.kernel.org Thu Jul 31 20:09:19 2014 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XCun0-0002z3-H8 for gcvg-git-2@plane.gmane.org; Thu, 31 Jul 2014 20:09:18 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751983AbaGaSJO (ORCPT ); Thu, 31 Jul 2014 14:09:14 -0400 Received: from mx1.imag.fr ([129.88.30.5]:41034 "EHLO shiva.imag.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751648AbaGaSJN (ORCPT ); Thu, 31 Jul 2014 14:09:13 -0400 Received: from clopinette.imag.fr (clopinette.imag.fr [129.88.34.215]) by shiva.imag.fr (8.13.8/8.13.8) with ESMTP id s6VI97Hk028947 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 31 Jul 2014 20:09:07 +0200 Received: from anie.imag.fr (anie.imag.fr [129.88.7.32]) by clopinette.imag.fr (8.13.8/8.13.8) with ESMTP id s6VI99wt029210; Thu, 31 Jul 2014 20:09:09 +0200 In-Reply-To: <53DA7C23.3090603@gmail.com> (Tanay Abhra's message of "Thu, 31 Jul 2014 22:55:55 +0530") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0.1 (shiva.imag.fr [129.88.30.5]); Thu, 31 Jul 2014 20:09:07 +0200 (CEST) X-IMAG-MailScanner-Information: Please contact MI2S MIM for more information X-MailScanner-ID: s6VI97Hk028947 X-IMAG-MailScanner: Found to be clean X-IMAG-MailScanner-SpamCheck: X-IMAG-MailScanner-From: matthieu.moy@grenoble-inp.fr MailScanner-NULL-Check: 1407434948.26981@+/Hv+nXO28TJyCYNAZOiag Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Tanay Abhra writes: > On 7/31/2014 10:22 PM, Matthieu Moy wrote: >> Tanay Abhra writes: >> >>> On 7/31/2014 9:25 PM, Matthieu Moy wrote: >>>> Tanay Abhra writes: >>>> >>>>> +void git_die_config(const char *key) >>>>> +{ >>>>> + const struct string_list *values; >>>>> + struct key_value_info *kv_info; >>>>> + values = git_config_get_value_multi(key); >>>>> + kv_info = values->items[values->nr - 1].util; >>>>> + if (!kv_info->linenr) >>>>> + die(_("unable to parse '%s' from command-line config"), key); >>>>> + else >>>>> + die(_("bad config variable '%s' at file line %d in %s"), >>>>> + key, >>>>> + kv_info->linenr, >>>>> + kv_info->filename); >>>>> + } >>>> >>>> Extra whitespace before }. >>>> >>>> Also, didn't we agree that it was a good thing to factor this >>>> if/then/else into a helper function? >>>> >>> >>> I have been thinking about it, wouldn't it be better to give users >>> a function like, >>> >>> git_config_die_exact(key, value); >>> >>> where user supplies key & value both and it would print the correct message based >>> on that. >> >> I suggested git_config_die_linenr(key, linenr), and I now realize it >> should take the value too. >> >> You're suggesting git_config_die_exact(key, value). Is it a typo that >> you forgot the line number, or is it intentional? If intentional, I >> don't think it solves your issue: >> >> [section] >> key >> key >> >> There are two errors in this file, and you need to provide a line >> number. key and value alone do not allow you to know which line the >> error is. You can use a convention like "complain on the first value >> equal to the argument", but I'm not sure that would always work. And >> that seems backward to me to reconstruct the line number since the >> function can be called from places where the line number is already >> known (while iterating over the string_list for example). > > Still the user would have to know that the linenr info is there. > First hear my argument, then we can go either way. > > Let's first see the previous code behavior, git_config() would die on the > first corrupt value, we wouldn't live to see the future value. > > for example, > > [section] > key // error(old git_config() would die here) > key = good_value > > [section] > key //again error > > Now for the new behavior, > > single valued callers use git_config_get_value() which will directly > supply the last value, so we don't see the first error value. > For such cases, git_die_config(key) is enough. Yes. And it is better than the old behavior which was dying on the erroneous value without giving a chance to the user to override the boggus value in a more specific config file (e.g. if your sysadmin messed-up /etc/gitconfig). But since git_die_config(key) is simpler to use for the caller, it's independant from git_die_config_exact()'s parameters. > The new git_config() works exactly as the old code, it would die > on the first case of erroneous value. Here, git_die_config_exact(key, value) > would be enough. Yes. But this callsite has the line number information, so it could use it. > The last case is git_config_get_value_multi(), here we iterate over the keys, > and then call git_die_config_exact(key, value) for the erroneous value. > (pros and cons: abstracts the error message implementation from the user > but there is an extra call to git_config_get_value_multi(), but its cheap and > we are dying anyway) This is the part I find weird. You're calling git_die_config_exact() on the first boggus value, and git_die_config_exact() will notify an error at the line of the last boggus value. I agree it works (if we give only one error message, it can be the first or the last, the user doesn't really care), but I find the implementation backwards. You have the line number already, as you are iterating over the string_list which contain it. So why forget the line number, and recompute one, possibly different, right after? So, I see only cases where you already have the line number, hence no reason to recompute it. -- Matthieu Moy http://www-verimag.imag.fr/~moy/