Re: No incremental undo in vi mode

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Fri, Feb 26, 2016 at 10:35 PM, Michael Giuffrida
<michaelpg@xxxxxxxxxx> wrote:
> When using vi bindings, my understanding is that `C-_` should trigger
> readline's undo behavior, as should `u` when in command mode.[1]

Zsh does not use readline.  It has its own editor with its own set of
key bindings.

> In zsh in vi mode, it just clears the whole line. So it's not useful for
> undoing the effect of glob expansion or other tab completion.

Are you sure you have C-_ bound to what you think you do?  With

bindkey -v
bindkey '\C-_' undo

I get the behavior you expect rather than the behavior you report.

What does

bindkey '\C-_'

output for you?