Subject: bug#29349: closed (Re: [Patch] Bug 29349: read_key_sequence is only partially recursive. This is a bug.)

From: [email-masked] (GNU bug Tracking System)
Date: Mon, 20 Nov 2017 18:16:02 +0000

Your bug report

#29349: read_key_sequence is only partially recursive.  This is a bug.

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to [email-masked].

-- 
29349: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=29349
GNU Bug Tracking System
Contact [email-masked] with problems

Subject: Re: [Patch] Bug 29349: read_key_sequence is only partially recursive. This is a bug.
From: Alan Mackenzie <[email-masked]>
To: [email-masked]
Date: Mon, 20 Nov 2017 18:12:27 +0000
List-Id: <debbugs-submit.debbugs.gnu.org>

Bug fixed in master.

-- 
Alan Mackenzie (Nuremberg, Germany).

Subject: read_key_sequence is only partially recursive. This is a bug.
From: Alan Mackenzie <[email-masked]>
To: [email-masked]
Date: Sat, 18 Nov 2017 09:38:43 +0000
List-Id: <debbugs-submit.debbugs.gnu.org>

Hello, Emacs.

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?

#########################################################################

As a second problem, is there any way, preferably at the Lisp level, to
determine that a key sequence is a menu key sequence?

-- 
Alan Mackenzie (Nuremberg, Germany).