bug#53590: 28.0.91; icompletion-vertical-mode gets stuck on 'M-x man RET awk'

[Van Ly]

On Sat, 29 Jan 2022, Eli Zaretskii wrote:

> Does the following command segfault when invoked from the shell outside
> Emacs?
>
>  man -k awk 2>/dev/null

The above command runs and completes as is expected.  Each manpage 
keyword entry produces a multiple line output in brief.

> If that command doesn't segfault, then what about the following one?
>
>  man -k awk 2>/dev/null | cat

The above fails as follows:

'''
% man -k awk 2>/dev/null | cat
zsh: segmentation fault  man -k awk 2> /dev/null |
zsh: done                cat
% echo $SHELL
/usr/pkg/bin/zsh
'''

Maybe the output redirect pipeline syntax for zsh is causing trouble.

Further to the original description of the problem, typing "awk" 
after M-x man RET produces

> M-x man RET a

There is a low wait of less than 2min more than 30sec, then the 
minibuffer shows

> M-x man RET a [No matches]

The text cursor is behind the "a" and typing "wk" for the second time 
immediately echoes in the minibuffer and shows

> M-x man RET awk [No matches]

And, as I described initially, the text cursor is positioned between 
"k" and "[No matches]", I type RET and then the manpage for awk 
quickly displays.

--
vl