Mailing-List: contact zsh-workers-help@zsh.org; run by ezmlm
Precedence: bulk
X-No-Archive: yes
List-Id: Zsh Workers List <zsh-workers.zsh.org>
List-Post: <mailto:zsh-workers@zsh.org>
List-Help: <mailto:zsh-workers-help@zsh.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on f.primenet.com.au
X-Spam-Level: 
X-Spam-Status: No, score=0.6 required=5.0 tests=BAYES_00,TO_NO_BRKTS_PCNT
	autolearn=no autolearn_force=no version=3.4.0
Date: Thu, 21 Jan 2016 14:51:20 +0100
From: Vincent Lefevre <vincent@vinc17.net>
To: zsh-workers@zsh.org
Subject: Re: prompt update and TRAPCHLD
Message-ID: <20160121135120.GC21104@cventin.lip.ens-lyon.fr>
Mail-Followup-To: zsh-workers@zsh.org
References: <20160114171631.GC12351@cventin.lip.ens-lyon.fr>
 <160114185941.ZM18307@torch.brasslantern.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <160114185941.ZM18307@torch.brasslantern.com>
X-Mailer-Info: https://www.vinc17.net/mutt/
User-Agent: Mutt/1.5.24-6551-vl-r83103 (2016-01-05)
X-Seq: zsh-workers 37718

On 2016-01-14 18:59:41 -0800, Bart Schaefer wrote:
> The right thing is to explicitly tell ZLE to update the prompt:
> 
> TRAPCHLD() {
>   psvar[1]=$RANDOM
>   [[ -o zle ]] && zle reset-prompt
> }  

There's something wrong with it:

cventin:~> where TRAPCHLD                                             <14:00:55
TRAPCHLD () {
        [[ -o zle ]] && zle reset-prompt
}
cventin:~> echo &                                                     <14:00:59

[1] 23998
[1]  + done       echo                                                          
TRAPCHLD:zle: widgets can only be called when ZLE is active

> Or perhaps your complaint is that the TRAP* function should run sooner?

I think I was surprised when doing some tests. I thought that there
was some race condition in my code because the TRAPCHLD was run too
soon, but that's the opposite! So, the problem is something else.

I've now a better view of what happens. I have something like:

updprompt()
{
  local njobs=$#jobstates
  echo "--> $njobs" > /dev/tty
  print -nP "\e]2;${njobs}\x07" > /dev/tty
  echo "--> $njobs" > /dev/tty
}

(the "echo ..." are mainly added for the test).

precmd() { updprompt }

TRAPCHLD() { if [[ -o interactive && -n $TTY ]] then updprompt; fi }

When I type "echo &", in the command line, I generally get:

cventin:~> echo &                                                     <14:45:58

[1] 29151
--> 1                                                                           
--> 1
[1]  + done       echo
--> 0
--> 0

with "0" in the terminal window title, but I sometimes get:

cventin:~> echo &                                                     <14:45:59

[1] 29153
--> 1                                                                           
[1]  + done       echo
--> 0
--> 0
--> 1

with "1" in the terminal window title.

Now, I don't understand how this is possible if TRAPCHLD is run
after the prompt is redrawn, i.e. after updprompt has completed
in precmd!

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)