Like {up,down}-line-or-beginning-search, this widget relies on
`$LASTWIDGET` being set to function correctly on subsequent invocations.
When asynchronous suggestions are enabled, and the widget triggers a
suggestion to be fetched, `autosuggest-suggest` will be called and
$LASTWIDGET will be set to it.
See technique used in `fast-syntax-highlighting`:
- ca2e18bbc9
- http://www.zsh.org/mla/users/2018/msg00424.html
Also see http://www.zsh.org/mla/users/2018/msg00432.html
In async response handler:
- We only want to read data in case of POLLIN or POLLHUP. Not POLLNVAL
or select error.
- We always want to remove the handler, so it doesn't get called in an
infinite loop when error is nval or err.
There is an upstream bug that prevents ctrl-c from resetting the prompt
immediately after a suggestion has been fetched asynchronously. A patch
has been submitted, but a workaround for now is to add `command true`
after the exec.
See https://github.com/zsh-users/zsh-autosuggestions/issues/364
For unknown reasons, the pty will occasionally quit running. In these
cases, we still want to remove it so that a fresh one can be created. We
don't actually need this check because error messages from `zle` and
`zpty` are redirected to /dev/null.
One sure way to kill all currently running pty's is to run `exit` in a
subshell. Even without zsh-autosuggestions loaded, the following works:
% zmodload zsh/zpty
% zpty -b foo cat
% zpty -b bar cat
% zpty
(31689) bar: cat
(31666) foo: cat
% $(exit)
% zpty
(finished) bar: cat
(finished) foo: cat
