Re: [BUG?] Very strange behavior, execution of a function is interrupted

[Sebastian Gniazdowski <sgniazdowski@gmail.com>]

Guys to state this more simply but also FUD-like: the little `read -q`
brings up front whole Zle-command-line machinery, with sched, zle -F,
waiting for inputs (select) on multiple file descriptors, running
callbacks. Author of a script that asks y/n with `read -q` would never
expect that he will run `sched' by it, embedding foreign scripts in
middle of his script. This should have some attention, i.e. should be
fixed.
On Sat, 1 Sep 2018 at 21:12, Sebastian Gniazdowski
<sgniazdowski@gmail.com> wrote:
>
> I've found the cause. `compinit' does `read -q' when occurring
> insecure directories. If this happens from `sched' with possibly Zle
> being active, then following call inside bin_read() uses Zle's
> raw_getbyte() to read a character:
>
> zleentry(ZLE_CMD_GET_KEY, izle_timeout, NULL, &val);
>
> This means that `read' can make all the rich side-effects of the regular
> command-line to activate. I think this has significant importance, is
> severe. I wouldn't expect the `read' builtin to bring up whole `zle -F'
> handling, waiting for inputs, invoking callbacks.
>
> Below test code confirms the above thesis. Its execution is recorded
> here: https://asciinema.org/a/199265 Basically, my problem is that
> Zplugin's scheduler gets invoked in nested manner because of
> compinit's `read -q' (I was doing stress tests with compaudit
> activating) and data structures go to improper state.
>
>
> FD=1337; setup() {
>     exec {FD}< <( sleep 1; echo run )
>     zle -F $FD -my-scheduler
>     echo "Sched call reporting being called"
>     read -q "?[y/n]?"
>     echo "Sched call reporting exiting"
> }
> -my-scheduler() {
>     local THEFD="$1"; zle -F "$THEFD"; exec {THEFD}<&- # remove zle -F handler
>     echo "Zle -F handler reporting being called"
> }
> sched +1 setup
>
>
> On Sat, 1 Sep 2018 at 00:01, Sebastian Gniazdowski
> <sgniazdowski@gmail.com> wrote:
> >
> > Hello,
> > it's quite a lost game to explain this, but I'll try:
> >
> > - there is a scheduler called from sched +1 and once from zle -F
> > - it detects timed-out tasks, moves them to ZPLG_RUN, then executes
> > them reading them from this array
> >
> > Problem: sometimes execution never reaches this line and beyond:
> > https://github.com/zdharma/zplugin/blob/7a24478e5862a1359b6cfb2887a792213be07e3a/zplugin.zsh#L1485
> >
> > Some cycles of the preceding loop are then also skipped.
> >
> > I feel very helpless in explaining this, maybe there's standard
> > questions sheet for situation where bug in exec.c is suspected?
> >
> > I know `break 2' inside a function will break out of loop that
> > contains the function call. But I don't know what could exit a
> > function. I have debug prints and observe this clearly. At the
> > mentioned line, no execution occurs, ZPLG_RUN isn't cleared, I get to
> > run some tasks twice.
> >
> > Twice when I checked, it was happening when zle -F was called so near
> > next second, that timeout'd tasks detection included two time slots:
> > "0" (0 seconds after first precmd, handled by zle -F) and "1" (1
> > second after first precmd, handled by sched +1).
> > --
> > Sebastian Gniazdowski
> > News: https://twitter.com/ZdharmaI
> > IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zplugin
> > Blog: http://zdharma.org
>
>
>
> --
> Sebastian Gniazdowski
> News: https://twitter.com/ZdharmaI
> IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zplugin
> Blog: http://zdharma.org



-- 
Sebastian Gniazdowski
News: https://twitter.com/ZdharmaI
IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zplugin
Blog: http://zdharma.org