A possibly needed workaround for <( ) process substitution

[psprint]

Hello,
in branch develop there's currently use of <( ... ) process substitution to do asynchronous calls:

zsh-autosuggestions/zsh-autosuggestions.zsh

Lines 717 to 725 in 681ffc7

	exec {_ZSH_AUTOSUGGEST_ASYNC_FD}< <(
	# Tell parent process our pid
	echo $sysparams[pid]
	# Fetch and print the suggestion
	local suggestion
	_zsh_autosuggest_fetch_suggestion "$1"
	echo -nE "$suggestion"
	)

I use the same technique in fast-syntax-highlighting, however, I add command sleep 0 (could make it command true) after the exec: https://github.com/zdharma/fast-syntax-highlighting/blob/e06288a617b12e8038fdf5bc4bd40b6a25ef5332/fast-highlight#L917-L918

The reason for this additional call are severe problems with Ctrl-C that occur when using {MYFD}< construct, as my investigation showed.

So in this issue I just want to mention that in case of any Ctrl-C problems, command true after exec should help.

[ericfreese]

Thanks for this! I was actually having issues with Ctrl-C on develop but wasn't sure exactly why and hadn't yet put in the effort to figure out what was going on. I'm busy for the next few weeks but I'll take a closer look at this before cutting a release from develop.

[ericfreese]

@psprint Did you ever figure out why exactly this was necessary? I'm really curious what's going on that makes ctrl-c stop working.

[ericfreese]

I've found something interesting that you may have also found. At least in my case, it seems the problem only occurs with the monitor option set (does not occur with it unset).

[psprint]

Interesting. I was tracking this for many days and when workaround appeared I was too tired to continue, so I dont know why this problem occurs

[ericfreese]

Fair enough. I'll see what I can find...

[ericfreese]

@psprint I've submitted a patch that fixes this issue upstream

http://www.zsh.org/mla/workers/2019/msg00252.html

[ericfreese]

FYI @psprint it looks like this workaround doesn't work for zsh versions older than 5.0.8.