I agree it's an ill defined problem ; but then, so is isearching for foo\|bar.

I disabled the beeping and screen flashing, so it doesn't bother me, but I get the point. 

In the end, it's mostly a matter of personal convenience. The patched behavior suits me better, and seems more consistent with the way regexp are handled.

Best,
Antoine 


On 31 Jan 2017 04:29, "Eli Zaretskii" <eliz@gnu.org> wrote:
> From: Juri Linkov <juri@linkov.net>
> Date: Tue, 31 Jan 2017 01:24:07 +0200
> Cc: 25562@debbugs.gnu.org
>
> You can try yourself using the minimal patch below that demonstrates your idea.
>
> But from what I see, it's not too good, using the recipe from your top post:
>
> emacs -Q
> M-<
> M-s w
> i
>
> After typing the letter “i”, isearch fails, beeps, flashes the screen,
> with a clear indication that something went wrong.  This is more confusing
> for a user, because now a user has to stop and think about what is wrong.

I think this is a consequence of the simple fact that "word search"
and "incremental search" contradict each other: as long as "the word"
was not fully specified, searching for it incrementally is not a
well-defined operation.