From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.bugs Subject: bug#27986: 26.0.50; 'rename-file' can rename files without confirmation Date: Wed, 16 Aug 2017 16:56:48 -0700 Organization: UCLA Computer Science Department Message-ID: References: <61980dde-3d68-7200-e7f4-98f62e410060@cs.ucla.edu> <1002ee73-0ab5-409b-831f-0c283c322264@cs.ucla.edu> <83o9rignt6.fsf@gnu.org> <83d17whl72.fsf@gnu.org> <8e6de468-600c-4f2d-a21a-c2ff3a63d065@cs.ucla.edu> <83zib0g221.fsf@gnu.org> <2bb4b7ee-6bf9-df3d-5cd8-ae7992b9f2e7@cs.ucla.edu> <83wp64fdc4.fsf@gnu.org> <83valnfv9u.fsf@gnu.org> <7f0c12f6-57eb-63b9-c296-e062cbf0710c@cs.ucla.edu> <83o9rffqfp.fsf@gnu.org> <83efsbfmij.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1502927835 28767 195.159.176.226 (16 Aug 2017 23:57:15 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 16 Aug 2017 23:57:15 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 Cc: p.stephani2@gmail.com, 27986@debbugs.gnu.org, rms@gnu.org, John Wiegley To: Stefan Monnier , Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Thu Aug 17 01:57:11 2017 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1di8BO-00070t-A9 for geb-bug-gnu-emacs@m.gmane.org; Thu, 17 Aug 2017 01:57:06 +0200 Original-Received: from localhost ([::1]:35483 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1di8BU-0001dL-U4 for geb-bug-gnu-emacs@m.gmane.org; Wed, 16 Aug 2017 19:57:12 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41563) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1di8BN-0001ca-7B for bug-gnu-emacs@gnu.org; Wed, 16 Aug 2017 19:57:07 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1di8BK-0006nO-2a for bug-gnu-emacs@gnu.org; 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Wed, 16 Aug 2017 16:56:49 -0700 (PDT) In-Reply-To: Content-Language: en-US X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:135850 Archived-At: On 08/16/2017 03:31 PM, Stefan Monnier wrote: >>> This should be quite rare. The only scenario I see matching your >>> concern is if the source is a directory, the destination is not >>> a directory name but is an empty directory and is not a symlink, and >>> the destination is not a descendant of the source. Although not >>> impossible, this will happen so rarely that it doesn't invalidate >>> the proposed change. > Paul's suggestion makes a lot of sense to me, but I don't quite > understand the above: why does the emptiness of the destination > directory matter? It's because the system call rename(A,B) always fails when B is a nonempty directory. Hence the proposed (rename-file A B) will fail if B is not a directory name but happens to name a nonempty directory, and therefore rename-file noisily fails instead of silently behaving differently in this case (which was Eli's concern). Conversely, if B is an empty directory then rename(A,B) can succeed (and thereby remove the old B) if all the other conditions are met.