[{"id":13206,"web_url":"https://patchwork.libcamera.org/comment/13206/","msgid":"<20201014124243.4hek53zkt7wgzfbp@oden.dyn.berto.se>","date":"2020-10-14T12:42:43","subject":"Re: [libcamera-devel] [PATCH 10/10] meson: Enable shadowed variable\n\twarning","submitter":{"id":5,"url":"https://patchwork.libcamera.org/api/people/5/","name":"Niklas Söderlund","email":"niklas.soderlund@ragnatech.se"},"content":"Hi Kieran,\n\nOn 2020-10-13 16:12:41 +0100, Kieran Bingham wrote:\n> Shadowing variables can lead to unexpected bugs where a code path\n> utilises a variable that may not have been intended by the developer,\n> leading to hard to find bugs.\n> \n> Enable warnings for shadowed variables as defined at:\n> https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wshadow\n> \n> As an effect of utilising -Werror, this will cause variable or type\n> shadowing to become a build-time error.\n> \n> Suggested-by: Laurent Pinchart \n> Signed-off-by: Kieran Bingham \n\nI like it!\n\nReviewed-by: Niklas Söderlund \n\n> \n> ---\n> \n> The reference here is that I lost around 2 hours digging into a bug that\n> looked like some other code path was calling a destructor or such, but\n> was because I had accidentally aliased a private member variable in the\n> constructor, so all my initialisation was lost after the constructor\n> completed.\n> \n> meson.build | 1 +\n> 1 file changed, 1 insertion(+)\n> \n> diff --git a/meson.build b/meson.build\n> index de15cc16da81..10423f523ca5 100644\n> --- a/meson.build\n> +++ b/meson.build\n> @@ -38,6 +38,7 @@ if cc.has_header_symbol('stdlib.h', 'secure_getenv', prefix : '#define _GNU_SOUR\n> endif\n> \n> common_arguments = [\n> + '-Wshadow',\n> '-include', 'config.h',\n> ]\n> \n> -- \n> 2.25.1\n> \n> _______________________________________________\n> libcamera-devel mailing list\n> libcamera-devel@lists.libcamera.org\n> https://lists.libcamera.org/listinfo/libcamera-devel","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 26690BEEE0\n\tfor ;\n\tWed, 14 Oct 2020 12:42:47 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id E5E3660E97;\n\tWed, 14 Oct 2020 14:42:46 +0200 (CEST)","from mail-lf1-x141.google.com (mail-lf1-x141.google.com\n\t[IPv6:2a00:1450:4864:20::141])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 6A32560E79\n\tfor ;\n\tWed, 14 Oct 2020 14:42:45 +0200 (CEST)","by mail-lf1-x141.google.com with SMTP id z2so3556965lfr.1\n\tfor ;\n\tWed, 14 Oct 2020 05:42:45 -0700 (PDT)","from localhost (h-209-203.A463.priv.bahnhof.se. 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charset=\"iso-8859-1\"","Content-Transfer-Encoding":"quoted-printable","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":13215,"web_url":"https://patchwork.libcamera.org/comment/13215/","msgid":"<20201015134601.GF3957@pendragon.ideasonboard.com>","date":"2020-10-15T13:46:01","subject":"Re: [libcamera-devel] [PATCH 10/10] meson: Enable shadowed variable\n\twarning","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Kieran,\n\nThank you for the patch.\n\nOn Tue, Oct 13, 2020 at 04:12:41PM +0100, Kieran Bingham wrote:\n> Shadowing variables can lead to unexpected bugs where a code path\n> utilises a variable that may not have been intended by the developer,\n> leading to hard to find bugs.\n> \n> Enable warnings for shadowed variables as defined at:\n> https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wshadow\n> \n> As an effect of utilising -Werror, this will cause variable or type\n> shadowing to become a build-time error.\n> \n> Suggested-by: Laurent Pinchart \n> Signed-off-by: Kieran Bingham \n> \n> ---\n> \n> The reference here is that I lost around 2 hours digging into a bug that\n> looked like some other code path was calling a destructor or such, but\n> was because I had accidentally aliased a private member variable in the\n> constructor, so all my initialisation was lost after the constructor\n> completed.\n\nIt's sometimes nice to be able to shadow variables, but I think the\ndebugging pain is too high of a cost for that.\n\nReviewed-by: Laurent Pinchart \n\n> meson.build | 1 +\n> 1 file changed, 1 insertion(+)\n> \n> diff --git a/meson.build b/meson.build\n> index de15cc16da81..10423f523ca5 100644\n> --- a/meson.build\n> +++ b/meson.build\n> @@ -38,6 +38,7 @@ if cc.has_header_symbol('stdlib.h', 'secure_getenv', prefix : '#define _GNU_SOUR\n> endif\n> \n> common_arguments = [\n> + '-Wshadow',\n> '-include', 'config.h',\n> ]","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 02D5ABE905\n\tfor ;\n\tThu, 15 Oct 2020 13:46:52 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 6C9F160E8D;\n\tThu, 15 Oct 2020 15:46:51 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 87D24605BF\n\tfor ;\n\tThu, 15 Oct 2020 15:46:49 +0200 (CEST)","from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi\n\t[62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 9B0F8556;\n\tThu, 15 Oct 2020 15:46:48 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"jys0F3TR\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1602769609;\n\tbh=H2ue5Y9CM1oTf5FBmfLS/7iiNY42+VSVAtkhf64TRtc=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=jys0F3TRJhWtqn0G4yLCveAnvCYMao0qoLIDKfiEmflTFBh0Yu5iBKiIus1O4isBP\n\tWWkWSVVnohazwZwz2aNzKNR39pZaDxpKPy5Ks1z2xnueQUDZwboQnRmoxgxjhyQ2K6\n\tlSeTyiOs9OC4xV6APDdtpK9kzXVJQqxef+BxVyKQ=","Date":"Thu, 15 Oct 2020 16:46:01 +0300","From":"Laurent Pinchart ","To":"Kieran Bingham ","Message-ID":"<20201015134601.GF3957@pendragon.ideasonboard.com>","References":"<20201013151241.3557005-1-kieran.bingham@ideasonboard.com>\n\t<20201013151241.3557005-11-kieran.bingham@ideasonboard.com>","MIME-Version":"1.0","Content-Disposition":"inline","In-Reply-To":"<20201013151241.3557005-11-kieran.bingham@ideasonboard.com>","Subject":"Re: [libcamera-devel] [PATCH 10/10] meson: Enable shadowed variable\n\twarning","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera devel ","Content-Type":"text/plain; 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