From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#17330: files.el cd-absolute overcome false negative from file-executable-p Date: Tue, 06 May 2014 10:17:49 +0300 Message-ID: <83k39zxtnm.fsf@gnu.org> References: <83r449zf3s.fsf@gnu.org> <92953814-A584-41C4-940A-E58514E423AB@bluewin.ch> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1399413728 24137 80.91.229.3 (6 May 2014 22:02:08 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 6 May 2014 22:02:08 +0000 (UTC) Cc: 17330@debbugs.gnu.org To: Philip Hodges Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed May 07 00:02:02 2014 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WhnQr-0002FQ-Qk for geb-bug-gnu-emacs@m.gmane.org; Wed, 07 May 2014 00:01:49 +0200 Original-Received: from localhost ([::1]:33373 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhZdo-0004H7-M0 for geb-bug-gnu-emacs@m.gmane.org; Tue, 06 May 2014 03:18:16 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:47124) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhZdg-0004Fq-2J for bug-gnu-emacs@gnu.org; Tue, 06 May 2014 03:18:13 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WhZda-0001v7-T8 for bug-gnu-emacs@gnu.org; Tue, 06 May 2014 03:18:08 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:34956) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WhZda-0001ux-Pv for bug-gnu-emacs@gnu.org; Tue, 06 May 2014 03:18:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1WhZda-0002Xp-1w for bug-gnu-emacs@gnu.org; Tue, 06 May 2014 03:18:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 06 May 2014 07:18:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 17330 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 17330-submit@debbugs.gnu.org id=B17330.13993606749766 (code B ref 17330); Tue, 06 May 2014 07:18:02 +0000 Original-Received: (at 17330) by debbugs.gnu.org; 6 May 2014 07:17:54 +0000 Original-Received: from localhost ([127.0.0.1]:52307 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1WhZdR-0002XR-Le for submit@debbugs.gnu.org; Tue, 06 May 2014 03:17:54 -0400 Original-Received: from mtaout24.012.net.il ([80.179.55.180]:55960) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1WhZdO-0002X9-9X for 17330@debbugs.gnu.org; Tue, 06 May 2014 03:17:52 -0400 Original-Received: from conversion-daemon.mtaout24.012.net.il by mtaout24.012.net.il (HyperSendmail v2007.08) id <0N5500O004VBAU00@mtaout24.012.net.il> for 17330@debbugs.gnu.org; Tue, 06 May 2014 10:15:15 +0300 (IDT) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by mtaout24.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0N5500NLW5HF6030@mtaout24.012.net.il>; Tue, 06 May 2014 10:15:15 +0300 (IDT) In-reply-to: <92953814-A584-41C4-940A-E58514E423AB@bluewin.ch> X-012-Sender: halo1@inter.net.il X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 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-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:88654 Archived-At: > From: Philip Hodges > Date: Tue, 6 May 2014 00:43:27 +0200 > Cc: 17330@debbugs.gnu.org > > After discovering that even C functions can be redefined, today I "activated an advice" so that all file-executable-p C code calls from Lisp return t. > No unexpected refusals, no noticeable downsides, no waiting months for C code changes to appear in a new official release. The solution is satisfactory in practice. So far as I am concerned, the case can be closed. Can we at least document the unreliability first though? I don't know what to document, since you never disclosed the details. Good documentation should not include FUD, it should include details that are understandable and actionable by users. Writing such documentation requires a good understanding of your situation, something we don't have in this case. > From the cygwin FAQ: "When working out the Unix-style attribute bits on a file, the library has to fill out some information not provided by the WIN32 API. It *guesses* ..." That's not directly related to the case in point, AFAIK (and yes, I do know what Cygwin does to emulate Posix permissions using Windows ACLs). > I understand your being curious as to exactly why cygwin cannot guess correctly for this samba mount without going to an awful lot of trouble. But we do already have several statements confirming that it is not usual or practical to even try. These make sense to me. They explain and confirm what I am seeing. The analysis does not need to be complete. It just takes one reproducible false negative in a realistic scenario that is not going to go away anytime soon. At least one of the platform library functions called by file-executable-p sometimes cannot be trusted. That's enough for me. Let's stop trusting it at all. It is a pity that you don't tell the details. The result will be that the problem is perhaps solved for you (using a recipe that many Emacs users will not know how to reproduce), but not for others. I urge you to reconsider. After all, the amount of words we've wasted here is surely large enough to describe your issue to the required depth.