Re: [PATCH] don't store temporary value returned from c_str()

diff --git a/c4/6210297b053e7f441beec1c17b74fb565733b4 b/c4/6210297b053e7f441beec1c17b74fb565733b4
new file mode 100644 (file)
index 0000000..966331c
--- /dev/null
+++ b/c4/6210297b053e7f441beec1c17b74fb565733b4
@@ -0,0 +1,79 @@
+Return-Path: <david@tethera.net>\r
+X-Original-To: notmuch@notmuchmail.org\r
+Delivered-To: notmuch@notmuchmail.org\r
+Received: from localhost (localhost [127.0.0.1])\r
+       by olra.theworths.org (Postfix) with ESMTP id 09AB9431FB6\r
+       for <notmuch@notmuchmail.org>; Mon, 29 Apr 2013 14:23:22 -0700 (PDT)\r
+X-Virus-Scanned: Debian amavisd-new at olra.theworths.org\r
+X-Spam-Flag: NO\r
+X-Spam-Score: 0\r
+X-Spam-Level: \r
+X-Spam-Status: No, score=0 tagged_above=-999 required=5 tests=[none]\r
+       autolearn=disabled\r
+Received: from olra.theworths.org ([127.0.0.1])\r
+       by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024)\r
+       with ESMTP id B1JMfqdcmV6O for <notmuch@notmuchmail.org>;\r
+       Mon, 29 Apr 2013 14:23:17 -0700 (PDT)\r
+Received: from tesseract.cs.unb.ca (tesseract.cs.unb.ca [131.202.240.238])\r
+       (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits))\r
+       (No client certificate requested)\r
+       by olra.theworths.org (Postfix) with ESMTPS id 8D177431FAF\r
+       for <notmuch@notmuchmail.org>; Mon, 29 Apr 2013 14:23:17 -0700 (PDT)\r
+Received: from fctnnbsc30w-156034082078.dhcp-dynamic.fibreop.nb.bellaliant.net\r
+       ([156.34.82.78] helo=zancas.localnet)\r
+       by tesseract.cs.unb.ca with esmtpsa\r
+       (TLS1.2:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.80)\r
+       (envelope-from <david@tethera.net>)\r
+       id 1UWvXP-00031x-6i; Mon, 29 Apr 2013 18:23:07 -0300\r
+Received: from bremner by zancas.localnet with local (Exim 4.80)\r
+       (envelope-from <david@tethera.net>)\r
+       id 1UWvXJ-0008IH-EY; Mon, 29 Apr 2013 18:23:01 -0300\r
+From: David Bremner <david@tethera.net>\r
+To: Vladimir Marek <Vladimir.Marek@Oracle.COM>, Jani Nikula <jani@nikula.org>\r
+Subject: Re: [PATCH] don't store temporary value returned from c_str()\r
+In-Reply-To: <20130427160540.GB17459@vi64-x3-2e-prg06.cz.oracle.com>\r
+References: <1366405933-17223-1-git-send-email-Vladimir.Marek@oracle.com>\r
+       <878v44qhop.fsf@nikula.org>\r
+       <20130427160540.GB17459@vi64-x3-2e-prg06.cz.oracle.com>\r
+User-Agent: Notmuch/0.15.2+84~g12d5e4e (http://notmuchmail.org) Emacs/24.2.1\r
+       (x86_64-pc-linux-gnu)\r
+Date: Mon, 29 Apr 2013 18:23:01 -0300\r
+Message-ID: <87y5c1uj4a.fsf@zancas.localnet>\r
+MIME-Version: 1.0\r
+Content-Type: text/plain\r
+X-Spam_bar: -\r
+Cc: notmuch@notmuchmail.org\r
+X-BeenThere: notmuch@notmuchmail.org\r
+X-Mailman-Version: 2.1.13\r
+Precedence: list\r
+List-Id: "Use and development of the notmuch mail system."\r
+       <notmuch.notmuchmail.org>\r
+List-Unsubscribe: <http://notmuchmail.org/mailman/options/notmuch>,\r
+       <mailto:notmuch-request@notmuchmail.org?subject=unsubscribe>\r
+List-Archive: <http://notmuchmail.org/pipermail/notmuch>\r
+List-Post: <mailto:notmuch@notmuchmail.org>\r
+List-Help: <mailto:notmuch-request@notmuchmail.org?subject=help>\r
+List-Subscribe: <http://notmuchmail.org/mailman/listinfo/notmuch>,\r
+       <mailto:notmuch-request@notmuchmail.org?subject=subscribe>\r
+X-List-Received-Date: Mon, 29 Apr 2013 21:23:22 -0000\r
+\r
+Vladimir Marek <Vladimir.Marek@Oracle.COM> writes:\r
+\r
+>> It's okay to use the result of .c_str() as long as the string object\r
+>> stays in scope, and none of the non-const member functions are\r
+>> called. Here, I think the problem is that TermIterator's overloaded\r
+>> operator*() returns a string object within the if block's scope, and it\r
+>> goes immediately out of scope. You could check this by adding\r
+>\r
+> Right, I overlooked that TermIterator creates temporary string (if I\r
+> understand you correctly).\r
+>\r
+>> fine too.\r
+>\r
+> I would prefer my change as it avoids creating another std::string. At\r
+> least I think.\r
+\r
+Would you mind updating your commit message to reflect the best guesses\r
+from this discussion? \r
+\r
+d\r