From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.bugs Subject: bug#50946: Emacs-28: Inadequate coding in hack-elisp-shorthands Date: Sat, 2 Oct 2021 20:07:26 +0000 Message-ID: References: <831r54einq.fsf@gnu.org> <871r54xnds.fsf@gmail.com> <87ee933bcj.fsf@gmail.com> <83pmsnbnci.fsf@gnu.org> <83k0ivbjbu.fsf@gnu.org> <83czonbhex.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="39324"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 50946@debbugs.gnu.org, joaotavora@gmail.com To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sat Oct 02 22:08:22 2021 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mWlJ0-000A5w-IT for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 02 Oct 2021 22:08:22 +0200 Original-Received: from localhost ([::1]:46330 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mWlIz-0008BB-Co for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 02 Oct 2021 16:08:21 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:33218) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mWlIi-0008Az-0d for bug-gnu-emacs@gnu.org; Sat, 02 Oct 2021 16:08:04 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:49098) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mWlIh-0005Fb-PC for bug-gnu-emacs@gnu.org; Sat, 02 Oct 2021 16:08:03 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1mWlIg-0001MD-A3 for bug-gnu-emacs@gnu.org; Sat, 02 Oct 2021 16:08:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Alan Mackenzie Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 02 Oct 2021 20:08:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 50946 X-GNU-PR-Package: emacs Original-Received: via spool by 50946-submit@debbugs.gnu.org id=B50946.16332052585186 (code B ref 50946); Sat, 02 Oct 2021 20:08:02 +0000 Original-Received: (at 50946) by debbugs.gnu.org; 2 Oct 2021 20:07:38 +0000 Original-Received: from localhost ([127.0.0.1]:60644 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mWlIH-0001La-J6 for submit@debbugs.gnu.org; Sat, 02 Oct 2021 16:07:37 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:51981 helo=mail.muc.de) by debbugs.gnu.org with smtp (Exim 4.84_2) (envelope-from ) id 1mWlIF-0001LM-EI for 50946@debbugs.gnu.org; Sat, 02 Oct 2021 16:07:36 -0400 Original-Received: (qmail 68952 invoked by uid 3782); 2 Oct 2021 20:07:28 -0000 Original-Received: from acm.muc.de (p4fe15ae2.dip0.t-ipconnect.de [79.225.90.226]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Sat, 02 Oct 2021 22:07:28 +0200 Original-Received: (qmail 16241 invoked by uid 1000); 2 Oct 2021 20:07:26 -0000 Content-Disposition: inline In-Reply-To: <83czonbhex.fsf@gnu.org> X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:216203 Archived-At: Hello, Eli. On Sat, Oct 02, 2021 at 18:00:38 +0300, Eli Zaretskii wrote: > > Date: Sat, 2 Oct 2021 14:45:52 +0000 > > Cc: joaotavora@gmail.com, 50946@debbugs.gnu.org > > From: Alan Mackenzie > > > > The five aspects I enumerated on my original bug report. Not checking > > > > for a properly formatted Local Variables: section > > > That is not part of the function in question, is it? It's in > > > hack-local-variables--find-variables, which we use everywhere. > > It is now. It wasn't when I raised the bug a day or two ago. > So this issue is no longer pertinent, right? It was pertinent to my observation, but is no longer so, given that you have reviewed the new C code. [ .... ] > > > > not going back at least 3000 characters > > > That is now fixed, right? > > No, it's not. In certain edge cases, it will go back fewer than 3000 > > characters. > Does the patch below solve this? I think it does, yes. Thanks! > > > > I worry, to a lesser degree, it is not entirely clear whether setting > > > > the elisp-shorthands variable in the first line of a short file should > > > > be valid or not. I don't think the current hack-elisp-shorthands is > > > > careful enough about this. > > > Why does it matter? Otherwise we could have the scenario where somebody sets elisp-shorthands in the first line of a file, finds it works, then types more into the file, saves the buffer, then finds when she visits the file again that it no longer works. This, I think, would be a Bad Thing. > > Because the first line definition should either be valid or not valid. > > Currently it works for a sufficiently small file, but not for a normal > > sized file. This, I think, is a bug. > No, I don't think it's a bug, at least not a bug specific to > shorthands. That's how file-local variables work in general. No, not quite. For normal file-local variables, having one set in the first line works regardless of the length of the file. It wouldn't for elisp-shorthands, where it would only work for short files. > > Say you have a file 3150 bytes long, which is less than 3000 characters > > in Emacs. Your function will load only 3100 bytes, less than 3000 > > characters, into the temporary buffer. It thus may fail to find a Local > > Variables section, even if this scenario is highly unusual. > This should be solved by the change below. Yes, thanks. > > Have you checked that things work if the first byte in your temporary > > buffer isn't at the start of a character? > I don't see why this matters, can you explain? It might matter, I simply don't know. I rarely type characters into Emacs which are longer than a single byte in UTF8. I don't know whether insert-file-contents does the Right Thing when there's half a character at point-min, then insert-file-contents inserts the other half of the character before it. I don't know to what extent normal Emacs functions work when there are invalid "characters" at point-min or point-max. If I were writing this function, I would want to check these things. You are an expert on Unicode, so you are far likelier to know how Emacs handles such things. > Here's the patch I promised: > diff --git a/lisp/shorthands.el b/lisp/shorthands.el > index b8204d6..6162efd 100644 > --- a/lisp/shorthands.el > +++ b/lisp/shorthands.el > @@ -40,7 +40,10 @@ hack-elisp-shorthands > (with-temp-buffer > (while (and (< (buffer-size) 3000) (>= from 0)) > (insert-file-contents fullname nil from to) > - (setq to from from (- from 100))) > + (setq to from > + from (cond > + ((= from 0) -1) > + (t (max 0 (- from 100)))))) > ;; FIXME: relies on the `hack-local-variables--find-variables' > ;; detail of files.el. That function should be exported, > ;; possibly be refactored into two parts, since we're only Thanks! I think it's right. -- Alan Mackenzie (Nuremberg, Germany).