From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.bugs Subject: bug#29349: read_key_sequence is only partially recursive. This is a bug. Date: Sun, 19 Nov 2017 12:34:56 +0000 Message-ID: <20171119123456.GA4576@ACM> References: <20171118093843.GA3819@ACM> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1511095090 8293 195.159.176.226 (19 Nov 2017 12:38:10 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 19 Nov 2017 12:38:10 +0000 (UTC) User-Agent: Mutt/1.7.2 (2016-11-26) To: 29349@debbugs.gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Nov 19 13:38:06 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 1eGOrN-0001o2-Of for geb-bug-gnu-emacs@m.gmane.org; Sun, 19 Nov 2017 13:38:05 +0100 Original-Received: from localhost ([::1]:52779 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eGOrU-0007fF-US for geb-bug-gnu-emacs@m.gmane.org; Sun, 19 Nov 2017 07:38:12 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:44034) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eGOrO-0007f8-BZ for bug-gnu-emacs@gnu.org; Sun, 19 Nov 2017 07:38:07 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eGOrL-0004bR-89 for bug-gnu-emacs@gnu.org; Sun, 19 Nov 2017 07:38:06 -0500 Original-Received: from debbugs.gnu.org ([208.118.235.43]:38167) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eGOrL-0004ae-3R for bug-gnu-emacs@gnu.org; Sun, 19 Nov 2017 07:38:03 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1eGOrK-0002uV-86 for bug-gnu-emacs@gnu.org; Sun, 19 Nov 2017 07:38:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Alan Mackenzie Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 19 Nov 2017 12:38:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 29349 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 29349-submit@debbugs.gnu.org id=B29349.151109507711176 (code B ref 29349); Sun, 19 Nov 2017 12:38:02 +0000 Original-Received: (at 29349) by debbugs.gnu.org; 19 Nov 2017 12:37:57 +0000 Original-Received: from localhost ([127.0.0.1]:46848 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eGOrF-0002uC-HA for submit@debbugs.gnu.org; Sun, 19 Nov 2017 07:37:57 -0500 Original-Received: from ocolin.muc.de ([193.149.48.4]:50635 helo=mail.muc.de) by debbugs.gnu.org with smtp (Exim 4.84_2) (envelope-from ) id 1eGOrD-0002u3-T1 for 29349@debbugs.gnu.org; Sun, 19 Nov 2017 07:37:56 -0500 Original-Received: (qmail 12450 invoked by uid 3782); 19 Nov 2017 12:37:54 -0000 Original-Received: from acm.muc.de (p548C7514.dip0.t-ipconnect.de [84.140.117.20]) by colin.muc.de (tmda-ofmipd) with ESMTP; Sun, 19 Nov 2017 13:37:53 +0100 Original-Received: (qmail 5527 invoked by uid 1000); 19 Nov 2017 12:34:56 -0000 Content-Disposition: inline In-Reply-To: <20171118093843.GA3819@ACM> X-Delivery-Agent: TMDA/1.1.12 (Macallan) X-Primary-Address: acm@muc.de 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:140088 Archived-At: Hello, Emacs. On Sat, Nov 18, 2017 at 09:38:43 +0000, Alan Mackenzie wrote: > In branch emacs-26. > I came across this bug whilst working on bug #29272 ("C-h k C-mouse-3" > followed by menu selection asks for more keys). > In a Linux tty using the GPM mouse package, doing read_key_sequence (the > C function in keyboard.c), when a menu action is activated, > read_key_sequence calls itself recursively to handle all the mouse > manipulation. > Unfortunately, the variable raw_keybuf_count is initialised to 0 in > r_k_s. This includes in the recursive call. This variable indexes the > global buffer raw_keybuf, which accumulates the raw events which make up > the key sequence. > The result of this is that the events in the recursive call overwrite > the stored events of the outer r_k_s call, leaving a mess. > r_k_s is static in keyboard.c and is called from three functions: > command_loop_1, read_menu_command (the one that gives the trouble), and > read_key_sequence_vs. > So I propose as a solution that raw_keybuf_count be initialised to zero > in two of these three functions, but not in read_menu_command (and no > longer in read_key_sequence). I've tried this, and it seems to work. > It has the disadvantage of being ugly, and it makes read_menu_command > only callable as a subfunction of r_k_s. > Has anybody any thoughts on this? Here is how I propose to solve this: (i) In keyboard.c, the static variables raw_keybuf and raw_keybuf_count will become pointers. They will initially point to a static buffer and a static integer. For safety's sake, they will be reinitialised to those static variables in command_loop_1(), just before the invocation of read_key_sequence(). (ii) read_key_sequence() will get a Lisp_Object buffer and a count variable as local variables. Around the call to read_char(), raw_keybuf{,_count} will be set to point to these locals, so that should read_char encounter a menu, its events will be stored in the local copy of the Lisp_Object buffer. (iii) On return from read_char, if any events are in the local buffer, they will be appended to the buffer in the enclosing scope. The global pointers raw_keybuf{,_count} will be restored to their previous values. In short, raw_keybuf and raw_keybuf_count will be "bound" to local variables around the call to read_char(). Comments? -- Alan Mackenzie (Nuremberg, Germany).